KiwiSDR Operating Information

Updated 28 April 2022

New Kiwi owners:

Be sure to initially give your Kiwi a connection to the Internet and let it update to the latest software release. This process can take up to 60 minutes. If you're using the software installed by the factory (v1.2) you may not hear audio due to recent browser changes preventing the autoplay of audio and video. This is especially true with Firefox.

The software version is displayed on the "Stats" tab of the main control panel. The image below shows a version of "v1.282"

The easiest way to update is to power-up or restart when a connection to the Internet is available on the local network. The Kiwi checks for new software whenever it starts.

If it is successfully updating you will get an "update in progress" message when attempting to connect.

There is also an "Update" tab on the admin interface (see below) for controlling various aspects of the update process.

Beagle root password:

Did your Kiwi not have a Beagle/Linux root password set and now it's asking for one?
Recent security changes have automatically applied a password to any root or debian account passwords that were blank/unset. The new password set is either the Kiwi admin password or, if the admin password is blank, the Kiwi's serial number as shown on the admin page network tab or written in the white silkscreen box on the top of the Kiwi circuit board. To find out what the password was changed to please see this forum post.

For everyone:
For owners / admins:
How it works

The KiwiSDR is always accessed over a network connection using a browser running on another computer or mobile device. This can be from your local network or by anyone on the Internet if you have chosen to make your KiwiSDR publicly available. The user interface is only moderately optimized for mobile devices and there are no mobile apps yet for Android or iOS. The software does not support attaching a monitor or keyboard/mouse directly to the Kiwi BeagleBone.

Connect to the local network using an Ethernet cable between the Kiwi and your Ethernet switch, router, cable modem or firewall. An IP address for the Ethernet port is usually assigned by a DHCP server that is likely to already be running on your network. See the network configuration section for complete details.

Please consider making your Kiwi publicly available to Internet users by listing it on Particularly if your Kiwi is located in an interesting or under-represented part of the world. There are options for limiting public access to a subset of the four available channels.

Just tell me how to connect to my local Kiwi

If this computer is on the same local network as your Kiwi try clicking on one of the two links below: If that doesn't work use one of the methods below to find the Kiwi's IP address. Then use the IP instead of "kiwisdr.local", e.g. Type this into the address bar of your browser.

More information about Kiwi networking.

List of third-party extensions and software packages

Here is a list of Kiwi extensions and related software packages available from third parties.
When installed the extensions will appear in the Kiwi extensions menu.

Software packages:

Installing the KiwiSDR and software

This additional Quick Start Guide gives information about: A printed copy of this guide is included in every KiwiSDR shipping box.

Network configuration

Additional information:
The two cases of network configuration
In certain circumstances you may not have to do any network configuration at all. The Kiwi will just work out-of-the-box after you plug into the local network. There are two cases. First case, local only use:
It is likely your local network already has a DHCP server that will automatically assign an IP address to the Kiwi. This function is usually performed by your network router. The kiwisdr.local hostname resolves to this IP address via software on the Kiwi and the host computer you're connecting from (the one running your browser). But the kiwisdr.local hostname may not be recognised by all systems, particularly Windows. For a workaround to this problem, or if you need to specify the IP address manually (e.g., see below for how to find your Kiwi's IP address.

Second case, public access:
For public access you face a couple of issues.
Allowing public access on port 8073
For the public to connect, your KiwiSDR must answer on port 8073 at a fixed public IP address. Although any port number, e.g. 80, can be configured (see below). If you are on a residential network a single public IP address is sometimes shared by multiple computers, usually via Network Address Translation (NAT). You must modify the NAT configuration of your router to route connections to port 8073 of your public IP address to whatever local IP address was assigned to your Beagle (port mapping). To do this you'll need the network information provided using the methods described below. If your router supports UPnP the Kiwi can create the NAT entry automatically.

The other issue is that port mapping requires the local IP address of your KiwiSDR be unchanging over time. After all, you have to enter a fixed local IP address when the port mapping entry is made. Your KiwiSDR was likely initially assigned a local IP address with DHCP (dynamic host configuration protocol) from your router. DHCP does not guarantee that the same local IP address will be assigned each time the KiwiSDR is booted. To solve this problem most routers have another table to assign local IP addresses based on the unique MAC address associated with the Beagle. The MAC address is provided using the methods described above. You must then pick an unused local IP address that is outside the range of local IP addresses that DHCP uses yet still part of your local IP address space.

For example, our local network uses the address block - and is allocated as follows:

IP address fixed address? yes router start of DHCP allocated space end of DHCP allocated space yes web server yes public KiwiSDR yes development KiwiSDR

The port mapping and fixed IP tables are then setup in the router as follows:

NAT port mapping:
IP address
port maps
IP address
port service 80 ----> 80 web server 8073 ----> 8073 public KiwiSDR

fixed IP assignment:
IP address
Beagle MAC host 1C:BA:8C:A1:BE:EF web server 84:EB:18:E2:0E:A2 public KiwiSDR 1C:BA:8C:E3:3D:0B development KiwiSDR

Using UPnP to open the router port automatically
Beginning with release v1.65 of the Kiwi software your router can be contacted by the Kiwi using the Universal Plug-and-Play (UPnP) protocol and asked to open port 8073 automatically. Not all routers support this protocol, or have it enabled by default. This Kiwi feature is designed to save you from performing this task manually which can sometimes be difficult if you are not familiar with Network Address Translation (NAT) rules and the operation of your router.

For security reasons this feature is disabled on the Kiwi by default. To activate, go to the network tab on the admin page (e.g. kiwisdr.local:8073/admin) and set the button called Auto add NAT rule on firewall / router? to "yes". After a moment a message should say:
Automatic add of NAT rule on firewall / router: succeeded
If there is a different message in any other color the automatic add didn't work and you'll have to add an appropriate NAT rule for port 8073 (or another port you've configured) to your router manually.

Finding the Ethernet IP address of the KiwiSDR
Figuring out the IP address assigned to your KiwiSDR is the first step in manual network configuration. In most network setups a DHCP server on your router will assign this IP address to the Ethernet port on the Beagle of your KiwiSDR. The problem is figuring out what this address is. Here are some suggestions:
Use to connect to the Kiwi
If your Kiwi is able to contact when it starts up it will register its local IP address. Then when a browser from a computer on the same local network connects to it will automatically be redirected to the Kiwi. The local IP address will appear in the browser address bar. If multiple Kiwis are present on the network the browser will display a table allowing you to connect to each Kiwi individually.

Use "kiwisdr.local:8073/admin" to connect to the Kiwi admin page
The network information about your KiwiSDR is available on the "network" tab at kiwisdr.local:8073/admin So if you can connect to the Kiwi this way the Kiwi itself can tell you its IP address for use in further network configuration. But this method may not always work.

Most versions of Windows don't recognize the kiwisdr.local hostname. Here is a workaround. But do not use this workaround for Window 10 or later. There appears to be some sort of conflict and using kiwisdr.local will result in connections that have lots of audio overrun problems. Use one of the other methods listed here to find the IP address.

If you install Apple iTunes for Windows then the Apple Bonjour mDNS-based location discovery software gets installed. Now kiwisdr.local should be recognized. It is possible to uninstall iTunes but leave Bonjour/mDNS working with the right Windows control-panel manipulation. We understand that future versions of Windows may include mDNS by default. So try using kiwisdr.local before using the workaround.

Read the IP address from the Beagle LEDs
Beginning with version v1.174 of the software, the four LEDs on the Beagle (lower board of the two board stack) will display an encoded status message. This message includes the IP address, either assigned by DHCP or set statically. See the section: Getting the IP address (DHCP-assigned or static) from the LED pattern.

Use the free Fing network scanner app for iOS/Android at
There are also free third-party network scanner apps. We use one called Fing for the iPhone / iPad. After the scan, look for an entry where the Ethernet MAC address vendor has decoded to "Texas Instruments". TI is the manufacturer of the processor chip on the BeagleBone where the Ethernet controller resides.

Check your router's list of DHCP-assigned IP address
Of course your router, or other device running DHCP, knows the IP address allocated to the Kiwi. If you know how to access this device you might be able to determine the latest "new" device added to the DHCP list and hence the IP address.

Specifying the connection URL
This is the second issue to consider for the case of a Kiwi with public access. The method used to establish a public connection to your Kiwi is specified in the connect tab on the admin page. This includes specifying your own domain name, using the detected public IP address of the Kiwi or specifying your own IP address. Also the advanced techniques described below.

Configuring the dynamic DNS update client (DUC)
An issue you must consider for public access is how the outside world will contact your Kiwi. Do you already own a domain name (e.g. and has your Internet provider assigned you a static public IP address? Great, you're all set. All you have to do is create a sub-domain, say and point it to your public IP. Now your Kiwi will be reachable at assuming you're using the default port 8073.

But for many people this is not the case. They don't own a domain and their relatively inexpensive residential Internet service supplies them a dynamic IP address that changes every so often. To overcome these issues what you want is something called "dynamic DNS (DDNS)" where a company like allows you to use one of their generic domain names. And also gives you a program (dynamic update client, "DUC") to run on your local computer that tells them when your ISP has changed your dynamic IP so the generic domain name can be updated.

To simplify this process beginning with release v1.83 a DUC for has been built into the Kiwi software and can be configured on the connect tab of the admin webpage. You can use either the free DDNS service that requires a manual acknowledgement every 30 days or one of their paid plans without this restriction. Go to and create a unique hostname for one of their generic domains (e.g. and setup an account. Then on the connect tab of the Kiwi admin page select "DUC domain" on the menu. Then enter the account information, host name and hit the "click to (re)start DUC" button. In the status field below you should see the response "DUC started successfully" or an error message if there is a problem. To start the DUC every time the Kiwi restarts change the "enable DUC at startup?" switch to "yes".

Configuring a reverse proxy
At this time no new requests to use the reverse proxy service are being accepted.

Multiple proxied Kiwis behind a single Internet connection New
It is possible to run multiple Kiwis using the proxy behind a single Internet connection. Do this by requesting one unique user key per Kiwi. Then give each Kiwi a unique internal and external port number on the admin page network tab (e.g. 8073, 8074, 8075 ...) Your router must have the external port open to each Kiwi. Consider using the Kiwi UPnP option on the admin page network tab to open the ports automatically if your router supports UPnP.

The situation is summarized in the following table:

Public URL to connect to the Kiwi Public IP seen by proxy server Network tab external port Network tab internal port Private IP on local network 8073 8073 8074 8074 8075 8075

Configuring an Ethernet static IP address
If you are unable if get your router to associate the Beagle Ethernet MAC to a fixed local IP then there is an alternative. It is now possible to configure the Kiwi to use a static local IP address rather than obtaining one via DHCP. You'll have to get initial access to the Kiwi using one of the methods above. But then you can go to the admin page (e.g. kiwisdr.local:8073/admin) and then the network tab and change from DHCP mode to a static IP appropriate for your local network. The Kiwi Beagle will use this IP address on the Ethernet interface when next booted.

Using a USB network connection for initial Beagle access
If your network is very limited and has no DHCP server at all you can get initial access to the Kiwi by using a USB cable between the Kiwi Beagle and another computer as the network connection (micro-USB for BeagleBone Green, mini-USB for BeagleBone Black). This is a standard feature of the Beagle and instructions are available here. Note that it requires the installation of a USB networking driver on your computer. Once logged into the Beagle root account using the SSH (Linux) or PuTTY (Windows) program setup a static address for the Ethernet interface by editing the file /etc/network/interfaces on the Beagle. Change the entry for eth0 from using DHCP to using a static address. Use the entry for usb0 a guide.

But note the Kiwi software itself does not support using USB networking. This method is only for gaining initial access to the Beagle in order to change the Ethernet configuration so the Ethernet can subsequently be used.

Using a serial connection
As a last resort it is possible to connect a serial cable between the Beagle and a host computer. You'll need to purchase a USB-to-serial cable that is designed to connect to the Beagle serial port header. More information is here. Be certain to buy a cable that presents 3.3V to the Beagle and not 5V (the 5V cables are more common). You'll need to remove the Kiwi board in order to access the Beagle's serial header. Use a serial com program to login to the Beagle at 115.2k baud as the root user with no password. Then edit the file /etc/network/interfaces and change the configuration of the eth0 (Ethernet) interface from dhcp to static. Use the settings for usb0 at the end of the file as a guide.

Point-to-point Ethernet connection to a host computer Updated
For step-by-step instructions on how to do this with Window 10 see this Kiwi forum post. This should works with most recent Windows versions.

Some users simply want to install an Ethernet cable directly between the Kiwi and a laptop or PC and not involve other equipment (like a router) and not involve the Internet. This might be because they are traveling or only have a wireless connection between their PC and an Internet access device that has no Ethernet ports. We now have a solution for this case.

Starting with the v1.47 release the Kiwi software uses something called avahi-autoipd which takes over when the Kiwi is unable to locate a DHCP server to get an IP address for the Ethernet port. A random-but-unique link-local IP address in the range is then assigned to the Ethernet. Similar software present on all modern Macs and PCs does the same thing. Now the PC and Kiwi should be able to talk to each other. Since you don't know what IP address has been assigned to the Kiwi you instead use the name kiwisdr.local. On Windows this currently requires the Bonjour/mDNS package to be installed with the workaround described here. Macs are already setup. So now you can connect to the Kiwi by using kiwisdr.local:8073/ and kiwisdr.local:8073/admin to administrate.

It's also now possible to observe the Beagle LEDs to see what IP address was assigned.

Note that it takes
more than 60 seconds
after the Kiwi boots before it decides there is no DHCP and it should assign a link-local address. So please be patient before trying to connect from the PC.

A question remains however. If your PC only has a wireless connection to the Internet, and your new Kiwi was delivered with an installed software version prior to v1.47 (which is going to be true for quite a while) and you can only plug the Kiwi into the PC, then what can you do? The answer is to download a special version of the Kiwi software from the Internet onto your PC. Then copy it to a micro-SD card. And finally re-flash the Kiwi on-board filesystem from the SD card. Follow the instructions here.

/admin web configuration interface

Almost all configuration and administration of the KiwiSDR is done through the admin web interface at kiwisdr.local:8073/admin (adjust hostname as required). Each tab at the top of the page selects a group of related configuration parameters or status information. A restart button for the server will appear when certain parameters are changed. Use it when you have made all of your changes in all of the tabs.

Restart, reboot and power off
The status tab has restart, reboot and power off buttons. Restart can be used when the server is behaving oddly. Reboot of Debian can be done if the system has been running for many days or weeks and seems to have problems that might be Linux related. It is especially important to use the power off button before removing power from the Kiwi as this first halts Debian in a safe fashion that will prevent any possible filesystem corruption.

The Kick button can be used to close all active user connections (i.e. kick everyone off the SDR). This is useful when there are users who have been logged in for a very long period of time.

The Inactivity time limit field can be used to limit the amount of time a user can be connected when not actively changing the SDR controls (i.e. parked on a specific frequency for a long period of time). The timeout period is reset as soon as some adjustment to the controls is made. A value of zero disables any time limit checking. This is the default.

Similarly the 24 hour per-IP address time limit field can be used to limit the amount of time a user from a specific incoming IP address can be connected during a 24 hour time period. This period is independent of the inactivity limit described above. A value of zero disables any checking. This is the default.


The configuration on the connect tab is used to define the URL used to connect to your Kiwi from the local network and, optionally, from the public Internet. Here also is the configuration of the DDNS DUC and reverse proxy as described in the network section of this document.


The sensitivity of your antenna will determine how the base waterfall colors will appear. We suggest changing the Initial waterfall min field to compensate. Here is an example of base waterfall colors that are "washed out" with too much green because the default value of WF min on the main control panel is too low at -110 dBFS: (click for larger)

Here is the same waterfall with WF min set to -80 dbFS: (click for larger)

Once you have found a good value of WF min set that value in the Initial waterfall min field on the Config tab of the admin webpage.

The Max receiver frequency menu allows the top reception frequency to be increased to 32 MHz. This is to accomodate some users who want to down-convert signals into the 30 - 32 MHz region. Note that due to the KiwiSDR ADC clock frequency (66.67 MHz) there will be increased aliasing and spurious responses above 30 MHz.

Configuration when using a down-converter
The Kiwi frequency scale and other places where the frequency appears and is entered can be adjusted to account for any VHF/UHF down-converter (transverter) you have installed ahead of the Kiwi antenna input. The Frequency scale offset (kHz) field is used for this purpose.

Enter the number of kHz necessary to bring the converted frequency to the correct position on the scale. For example to map 50-52 MHz to 28-30 MHz place 22000 kHz in the field (50000 - 22000 = 28000). To map 144-148 MHz to 28-32 MHz set the field to 116000 kHz (144000 - 116000 = 28000) and set the Max receiver frequency menu selection to 32 MHz to get the extended receiver coverage. Inverted tuning when the converter uses a high-side LO is not yet supported (common for 23 cm / 1296 MHz converters).

The Coverage frequency low/high fields on the Public tab help use the correct frequency icon if you have listed your Kiwi there. Enter the frequencies covered by your down-converted setup. For example setting 118000 and 138000 in the fields will make display the icon "Airband". For other frequencies a frequency range in MHz will be displayed. So if you entered 50000 and 52000 then "50MHz - 52MHz" will be displayed.

The coverage fields can be used even if you are not using a down-converter. Suppose you have a Kiwi specializing in the AM MWBC band with attenuation outside those frequencies. You could set the fields to 540 and 1710 and "0.5MHz - 1.7MHz" would be displayed.


Map field
Note: Consider specifying coordinates that don't reveal your exact location. You can get the "Google format" map reference by Googling the name of your location (town etc.), clicking on Google maps from the search result, then clicking on the "share or embed map" item from the Google maps menu at the top left. Place in the Map field the last part of the link that begins with "" You can use the check map button to verify.

Grid square field
If you are not familiar with grid squares just click on the check grid button. A webpage will appear where you can enter your location name and receive a 6 character grid square identifier to enter in the field.

You can replace the default startup background photo with your own. Scale a photo file (jpeg, png, etc.) to be 350 pixels high. Starting with the v1.17 release there is a "file chooser" dialog so you can download the file to the Kiwi directly using the admin page. Although there is a Photo height field, changing it from 350 pixels currently doesn't work. Change the Photo title and Photo description fields as appropriate for your new photo.

The Owner info field allows you to display a message, including HTML, in the middle part of the top bar. Add your own logo here, short message or maybe a Paypal donation button to help defray your Internet costs for a publicly-accessible Kiwi.

Note that the Title field can contain HTML, like a link, just like the Status field even though there is no preview shown.


Note: Your Kiwi will appear on other sites like and if it is registered on

Note: Consider specifying coordinates that don't reveal your exact location, although the various maps add some dither to the location when zoomed-in as a privacy measure.

Registration on
On the Public tab are the parameters for registration. No API key is necessary. Just fill-out your listing information (name, location, etc.) and set the register switch to Yes. The registration status field should eventually show a message (this can sometimes take several minutes).

Make sure your location on the various map sites (e.g. shows the correct latitude and longitude. A common mistake is not specifying a negative longitude for the Americas or a negative latitude for locations in the southern hemisphere (we've made this mistake ourselves). You can use the check map button to verify. Note that the latitude and longitude are entered as signed decimal degrees, surrounded by parenthesis, e.g. "(-37.631016, 176.172019)". Not hours-minutes-seconds, no "N S E W" notation, no "degree" symbols, etc. If you zoom in you'll notice that the map sites dither the location a fair amount to help protect your privacy.

If the GPS is running, and has a fix, a blue button labeled set from GPS will appear. Use it to fill-out the location field automatically. The same is true for the grid square field.

See Configuration when using a down-converter for a description of how to use the Coverage frequency low/high fields.


The DX tab (not available on mobile devices) controls the content displayed in the DX label and band bar areas above the frequency scale. And also the "select band" menu on the main control panel. As you make changes they should be immediately reflected in all active user connections (except for file import discussed below which requires a restart).

Changes are saved as you type. The message Changes saved will appear when a save occurs.

It is extremely important that you maintain timely backups of the label database. Especially if you've spent many hours carefully curating an extensive, customized set of labels. Use the Export:
buttons to download a copy of the labels onto the computer running the browser.

The band bar and select band menu information is stored in the normal Kiwi configuration file. This file is saved, along with everything else, when you make a full system backup to SD card (see admin page "Backup" tab). You could also backup the files individually using a file transfer program such as WinSCP. The files are named:

There are four sections that can be shown or hidden using the
buttons on the left. They are:
DX labels Defines the labels themselves.
DX type menu Defines content of Type menu appearing in DX labels section above.
Band bars Defines content of band bars and select band menu on user page.
Band service menu Defines content of Service menu appearing in Band bars section above.

If you hover the mouse over the icon a popup will appear with additional information.

DX labels
The fields are the same as those in the user connection DX label edit panel.

buttons will duplicate and delete, respectively, a label entry. The duplicate function allows a new label to be created before the first and after the last existing entries, or anywhere in-between.

The button allows the optional schedule information to be added. If the schedule is the default (always active, 0000 - 2400, 7-days) then the schedule controls are not displayed to save screen space. Use the button to reset the schedule to the default. More information about label schedules.

There are search controls at the top right for the Freq, Ident and Notes fields. A matching field is highlighted in yellow (closest match for frequency). Type the enter/return key to search for the next occurence of the Ident or Note. The searches will wrap. The frequency is in kHz and MHz notation can be used e.g. 7M versus 7000

See the end of this section for a discussion of editing the dx.json file directly.

DX type menu
The Type menu in the DX labels section above has some values associated with the default dx.json file. But just as with the DX labels you can change the type values to be whatever you like.

However, it is important to understand how changing the type values will effect existing labels. If you have labels that use a particular type, let's say using the type menu name associated with the T1 entry on the DX type menu section. And then you clear the Menu entry name field for T1. What should happen to the Type menu? The answer is that a temporary name called, in this case, (T1) appears in the menu to remind you there are still labels using the T1 definition. If you subsequently change the type name to something non-blank the menu and label will follow the change.

You can define up to 14 different type entries. The 15th type is used in implementing masked frequencies and cannot be changed or removed.

The HTML color name field accepts all HTML color name specifications, including by name, hex value (e.g. #6789ab), or specific RGB/HSL value (e.g. hsl(300, 75%, 95%)). Color utilities like HTML color picker or color names by shade are useful.

For reference, the colors used with the EiBi labels are:
cyan hsl(300, 100%, 80%) deepSkyBlue
silver hsl(50, 100%, 70%) peachPuff
mediumAquaMarine hsl(270, 100%, 80%) hsl(180, 100%, 80%)
hsl(70, 100%, 45%) springGreen hsl(0, 100%, 75%)

Band bars
These next two sections control the band bars seen above the DX labels and frequency scale. And also the content of the select band menu in the main control panel.

The order of entries in the band bars section exactly determine the content of the select band menu. So for example it is important that all entries with the same Service type are grouped together so they appear under a single service heading in the menu.

The select band menu can define band bars and also single frequencies commonly used that do not have an associated band bar (e.g. the time stations). For this reason the ITU / Visibility menu contains the two entries show on band scale only and show on band menu only. The other menu entries, including any, always imply the entry will appear on both the band scale and in the band menu. For a single frequency entry set the Min and Max frequency values equal.

The ITU Region 1|2|3 selection filters when the entry will be shown based on the Kiwi ITU region configuration. Note that entries with ITU region specified typically have different values in the Chan field to account for the different channel spacing in those regions.

The Band name value is the name used in the menu and/or band bar. The band bar name is also augmented by the Menu entry name (service name) and optional Long name fields described below.

An entry in the Band freq/mode field sets a specific frequency and mode when a select band entry is selected. For example this is how the time station entries work. You could e.g. use this to select AM mode and a specific frequency in the AMBC band.

It is possible to have Min and Max frequency values in this list larger than 32 MHz for when a frequency offset is being used (i.e. downconverter/transverter operation).

Band service menu
This section defines the Service menu in the preceding section. The HTML color name field has the same specifications as described above. An example of how the resulting band bar will look with the given color and service name appears on the right.

The two name fields here, Menu entry name (service name) and Long name and the Band name in the preceding section are used in slightly different ways to construct naming in the select band menu and the band bars themselves.

Let's consider a service name of Broadcast, a band name of 41m and a long name of Shortwave Broadcast. In the select band menu 41m will appear under the Broadcast heading, along with any other bands with that same service name. The band bar will have a different name depending how wide it is as a function of the current zoom level. At a minimum 41m will be shown (unless the bar is so short that no text fits.) If it fits 41m followed by Broadcast will be shown. But since the long name is not blank in this example 41m followed by Shortwave Broadcast will be the actual name shown.

Editing the dx.json file directly
In some cases it may be easier to make a large number of changes using a text editor on another computer. The Export:
and Import:
buttons can be used to copy the label database file. Note that as soon as you import (upload) the Kiwi must be immediately restarted (you will be prompted). If any illegal format JSON or CSV is detected in the labels after the restart error messages will appear in the Kiwi log and a count of the number of bad labels will appear on the DX tab. The bad labels are discarded. So to repair you must fix them in the file and import again.

Each JSON file entry has a number of fixed fields followed by some optional parameters.
[ Freq (kHz), "Mode", "Ident", "Notes", { parameters, JSON object } (optional) ]

The parameters can be any combination of:
"Tn":1 Type code linking to a type menu entry, n is 1 to 15.
"T0":1 is always omitted to save file space.
"lo":Hz, "hi":Hz Passband
"o":Hz Offset
"d0":DOW_value Day-of-week schedule value, MTWTFSS = hex bits 0x7f,
example: M_W__SS = 7'b1010011 = 0x53 = 83.
"b0":hhmm, "e0":hhmm Begin and End schedule times (UTC)
"p":"extension" Extension

Some examples:
[ 5000.00, "AMN", "WWV", "time signal" ] Both Ident and Notes fields
[ 7038.60, "USB", "WSPR", "" ] An empty Notes field
[ 8653.00, "USB", "FSK", "", { "T1":1 } ] Type is second entry (T1) in DX type menu
[ 8681.00, "USB", "FAX", "NMC",
 { "lo":800, "hi":2200, "p":"fax" } ]
Passband: lo=800, hi=2200 Hz
Extension: FAX
[ 2500.00, "AMN", "BPM", "time signal",
 { "b0":730, "e0":100 } ]
Schedule (UTC): begin=0730, end=0100,
[ 4458.00, "USB", "XPB", "MFSK",
 { "d0":33, "b0":2050, "e0":2100 } ]
Schedule (UTC): begin=2050, end=2100,
DOW: Tue,Sun = 7'b0100001 = 0x21 = 33.

Some characters in the string fields (e.g. Ident, Notes) are encoded using a subset of
URL percent (%) encoding. They are listed below. These encodings are used in any exported JSON or CSV files. When you edit a file you must use the encoding, except you can enter UTF-8 characters directly. The UTF-8 will be encoded when the files are imported and subsequently re-exported.
Character(s) % encoding
%00 - %1f Use \n in the Ident or Notes field for a multi-line label.
No reason to use the other control chars.
" %22 Double quote.
% %25
\ %5c
delete %7f No reason to use this.
%80 - %ff You can enter UTF-8 characters in your text editor
but they will be encoded when the file is imported
and subsequently re-exported.

For CSV files the semicolon ; is the field separator character. The first line contains a legend describing the order of the fields. To include the double quote character " inside a string field, like the Ident or Notes fields, repeat it twice. This is a standard escape mechanism supported by spreadsheet programs.
For example: Notes field with ""double quotes"" embedded
Or use the %22 encoding for a double quote. When imported, the CSV file is converted to JSON and stored in the usual dx.json file.


If you don't have a Ham radio callsign, but would like to contribute your Kiwi's WSPR decodes to, set the Reporter callsign field to something like "SWLRF82". Where "SWL" is the well-known abbreviation for "shortwave listener" and "RF82" is a 4-character grid square describing your Kiwi's general location available from this site. There are other conventions as well, e.g. "SWL/ZL" where "ZL" is a Ham radio callsign prefix for New Zealand.


Public/private channels
On the admin security tab you will find a setting allowing you to disable the password prompt for a subset of the 4 channels (none, 1, 2 or 3) when an overall user password has been set. This allows you to divide the 4 channels into two sets: a publicly-available set requiring no password and a private set requiring a password. Owners of the more popular Kiwis have long complained that the channels are always full and they, or their friends, can never get in without restarting the server and dumping everyone off. It is hoped this feature may persuade some owners of completely closed Kiwis in desirable locations to make some of their channels public.

Controlling the server from a Beagle root login

Although most of the control and configuration of the server is accomplished via the admin webpage, there are some shell commands that can be used. Login to the Beagle from another computer as the root user. On another computer use the SSH program with Linux, or PuTTY on Windows. Change to the Beagle_SDR_GPS directory. A shortcut for this is the cdp command alias (change directory project). Once there a number of commands can be used to control the server:
  • ku (Kiwi up) Restart the server.
  • kd (Kiwi down) The SDR stops and returns a "down for development" message.
  • ms (make status) Reports server status and last log messages.
  • mu (make users) See who's been using your KiwiSDR.
  • ml (make log) Prints all the log files.
  • msl (make short log) Prints just the recent log file.
  • up (update) Forces a software update to the latest version on Github.
  • There are a number of others that are less useful. See /root/.bashrc and the Makefile for more information.
Most of these features as also available on the admin webpage. For example the log files can be viewed under the Log tab and the server can restarted with a button on the Control tab.

Special access-related configuration

There are several configuration options related to admin access of the Kiwi. For security reasons these are specified by files in the
directory on the Kiwi rather than directly in the web-based admin configuration. The file names and their contents are:
  • opt.admin_ip -- Limits admin connections to a single IPv4/IPv6 address (put IP address in the file). Multiple addresses and domain names are not currently supported.

  • opt.no_console -- Disables the console tab function on the admin page which effectively prevents root shell access from the web interface. Just create a file of this name. The file contents don't matter (e.g. file can be empty). This has no effect on any other security measures you may, or may not, have taken on the Kiwi (e.g. set a root password, changed sshd configuration). Therefore note you may still be able to login as root to the Kiwi using ssh/PuTTY.

Manual frequency calibration

If your GPS antenna is connected and receiving signals then the KiwiSDR clock frequency will be continuously calibrated automatically. If not you can perform a manual calibration. There are two sources of clock oscillator error. Inherent error due to manufacturing variations and error that changes with the ambient temperature. A manual calibration will correct the inherent error, and error due to the current temperature, but will not track error due to future temperature changes. Follow these steps:

Tune to a station transmitting a carrier on a known, accurate frequency like a time station (WWV 15 MHz in this example). Use the highest frequency station possible as this will show the most offset (i.e. an HF station rather than LF/VLF). Zoom all the way in and select the exact center of the carrier line in the waterfall with the mouse. The yellow vertical bar of the passband should align with the waterfall carrier line. See image below. Note the WWV -/+100 and +600 Hz modulation shown in addition to the carrier (frequency scale ticks are 100 Hz).

Right-click to bring up the menu and select cal ADC clock (admin). You will be prompted for the admin password if necessary. On a laptop there are usually options for generating a right-click if your trackpad doesn't have left/right buttons (i.e. with a two-finger tap, control-tap, etc.)

A confirmation dialog will appear showing how far the clock must be adjusted to get to the nearest 1 kHz. In this case +81 Hz is needed to get the carrier on 15000 kHz. The normalized ADC clock adjustment in parts-per-million (ppm) is shown, 4.9 ppm in this case.

As soon as confirm is clicked the waterfall will shift to reflect the new calibration. This new calibration value will be remembered and applied on every Kiwi restart. It will be reset to zero when GPS corrections are occurring.

Optionally downloading the software (if you lost the SD card etc.)

This procedure is normally not necessary since each KiwiSDR comes with a micro-SD card containing all the software. In addition, if you purchased the Kiwi "kit" version, which includes a BeagleBone Green (BBG), the software is already pre-installed on the BBG. However there are cases where you might want to download the software: your micro-SD card doesn't work or you want to get a head-start on installing the software if you've ordered just the Kiwi board and are supplying your own Beagle.

Debian 8 -- BBG/BBB only

In almost all cases for the BBG/BBB you will want to restore to the Debian 8 image. An upgrade to Debian 10 requires a more complicated procedure described below.

Debian 10 -- BBG/BBB only

If you are reading these instructions because you want to upgrade your Kiwi from Debian 8 to Debian 10 then you must follow the detailed instructions given on the Kiwi Forum. Simply following the procedure below is NOT sufficient to fully upgrade to Debian 10 (example: your Kiwi's configuration from Debian 8 will not be restored!).

Debian 9 -- BBAI only

For BBAI, the flasher image below only restores the BBAI to factory state. No Kiwi software is installed. Follow the procedure on the Kiwi Forum to install the Kiwi software. Be careful: A BBAI-based Kiwi will not run using the BBG/BBB Debian 8 or Debian 10 image.

In case you are unfamiliar with the process of installing software on a Beagle here's how it works. The micro-SD card is what's known as a 'flasher'. Each time you boot your Beagle from the micro-SD card it will copy its contents to the on-board flash memory (eMMC) of your Beagle. In other words all the software previously installed on your Beagle will be
completely overwritten and lost
. So be very careful in using a flasher micro-SD. Remember, the copy operation will only occur when you boot from a micro-SD flasher. It is possible to insert a flasher micro-SD into a running system so that it may be read or re-written like any other card. But be certain to remove it immediately after you're done. Otherwise the next time you reboot the Beagle the flashing operation will begin (if the card is still a flasher). Even we make this mistake occasionally and it is very annoying to lose all your work that is stored on the Beagle's on-board filesystem.

An image file from the Internet must be downloaded and copied to a micro-SD card to turn it into a flasher. This can be done on the Beagle itself running whatever version of Debian Linux happens to be installed. It is also possible to use programs on Macs and PCs that write image files to micro-SD cards. Proceed as follows.
  • Obtain a micro-SD card at least 8 GB in size. It is best not to use the one delivered with your Kiwi as that should be saved as an emergency backup (unless it doesn't work and you're repairing it.)

  • Mac & Windows:
    • Debian 8 -- BBG/BBB only
      • Download this 460 MB .img.xz file to your Mac/PC
        (SHA256: 7723f566c5513916a3977c11706ac86e071f8c0cbc177b145098fab842524554)
    • Debian 10 -- BBG/BBB only
      • Download this 710 MB .img.xz file to your Mac/PC
        (SHA256: 676301a5ad0c52417011fd257da9ffa3106ad33af41c8b2273d49d44527e14f3)
    • Debian 9 -- BBAI only
      • Download this 521 MB .img.xz file to your Mac/PC
        (SHA256: 2177a191af9aaceee768921f0b2442e36fbb9369acb921957499d5e68b6447ec)
    • Follow these Mac/PC-specific instructions for writing the file to the SD card. You may have to download one or more programs (e.g. for Windows Win32DiskImager and 7-Zip)
    • Note that you must use a program like 7-zip to expand the .img.xz file into a (much larger) .img file before using the .img file with the program that writes the SD card.
    • Some of these programs can overwrite your PCs hard drive if the wrong device for the SD card is specified. So follow the instructions very carefully.

  • Beagle / Debian Linux:
    • Make sure the Beagle has a connection to the Internet.
    • Login to the Beagle from another computer.
      • From Linux: "ssh root@(Beagle_ip_address)"
      • From Windows: use "PuTTY" program or similar. Login as user "root".
      Where (Beagle_ip_address) is, e.g.
      Some Debian/Linux systems don't allow you to network login as user "root". Instead, login as user "debian" and use the command "sudo su" to get root privileges.
    • Debian 8 -- BBG/BBB only
    • Debian 10 -- BBG/BBB only
    • Debian 9 -- BBAI only
      • There is no script for the BBAI currently. Follow the BBAI instructions for Mac & Windows above.
    • Script will download large KiwiSDR software distribution file from
    • Script will show checksums. Make sure they match so you know download is good.
    • When script asks, insert a micro-SD card (8 GB or larger) into Beagle.
    • Script writes micro-SD card. This takes about 40 minutes. Depends on size and type of micro-SD card.
    • If you want the Beagle you are now using to be re-flashed with the KiwiSDR software then hit return key when asked to reboot. Remember: all previous Beagle software will be erased. Otherwise hit control-C to stop script.
After you have an SD card with the flasher image insert it into the Beagle and power-up. When booted from the SD card the LEDs will display a "back-and-forth" pattern as the image is copied to the Beagle on-board filesystem. The Beagle will power off when done (all LEDs will go dark). Takes about 5 minutes for a Class-10 SD card. IMPORTANT: Remove the micro-SD card when finished.

Your Beagle now has the KiwiSDR-customized version of Debian installed and a snapshot version of the KiwiSDR server software itself. When the KiwiSDR server is first run it will automatically update itself to the latest version by downloading from Github since the download image is always older than the most current version.

If you are doing a Debian 8 to Debian 10 upgrade then return to the Kiwi Forum for instructions on completing the upgrade.

† Note that if you have an older Beagle running the Angstrom distribution, instead of the more recent Debian, this script won't work. Use the micro-SD delivered with your Beagle or follow the various guides on the Internet showing how to upgrade your Beagle to Debian first.

KiwiSDR discussion forum

The KiwiSDR forum is here.

Viewing the source code change log

To see the comments from recent changes to the source code look at the Github change log. If any comment there is followed by an ellipsis box (...) click on it for more information about the change.

By popular request there is also a summary CHANGE_LOG file that is easier to understand than the detailed Github commit log.

Power supply advice

The Kiwi must be powered using the round connector DC jack on the Kiwi board (2.1mm ID, 5.5mm OD). Powering over the micro-USB connector of the BeagleBone Green doesn't work because it can't supply enough current. The power management chip of the BBG will not allow more than 500 mA to flow on this connection. The Kiwi plus BBG draws over 1A and peaks approaching 1.5A.

Don't use the wrong size DC plug

Also note that many power supply DC plugs are actually meant for 2.5 mm center pin jacks, not 2.1 mm the Kiwi uses. This means they will fit loosely in the Kiwi jack and may cause unexpected power downs as the Kiwi or cable are moved around.

Be careful when using precision bench supplies

Be sure to set the current limit high enough (>= 2A) to catch the peak current requirements of the Kiwi and Beagle. A precision supply will react much more quickly to over-current situations than an ordinary linear supply using a big output capacitor to ride through peak current demand. A bench supply will instantly drop the output voltage the moment the current limit is reached. We've had several users observe bizarre behavior using precision supplies (random Beagle shutdown, SD card write failures, repeatable server "freeze" during certain operations, etc.)

Under-voltage due to cable voltage drop

The power management controller chip (PMIC) on the Beagle will refuse to power up the Beagle and Kiwi if the 5V input is below about 4.75V. Worse, if a momentary increase in peak current draw causes the input to drop below 4.75V due to losses in the cable the Beagle will unexpectedly power down. This problem has been seen by several customers and even ourselves. It is caused by cables with insufficient wire gauge. See this forum post. A 22 AWG USB-to-2.1mm adapter cable known to work is this one from Adafruit.

Using a quiet linear power supply to power the KiwiSDR / Beagle will significantly reduce received noise, particularly on the LF/MF bands. This is because almost all of these small line-powered units are switch-mode power supplies (SMPS) with inadequate filtering. The switching frequencies are typically in the 20 - 170 kHz range with harmonics sometimes extending well into the shortwave bands. Worse, the oscillators are almost always unregulated resulting in unstable carriers many kHz wide. Their emissions might meet regulatory requirements but that doesn't stop them from wrecking havoc when used to directly power an SDR. Check out this interesting article comparing the emissions and safety of common 5V USB SMPS chargers.

Transformer-based, regulated linear supplies are now more difficult to find. Particularly the wall-mount (plug-pack) type. This is partly due to new energy conservation laws requiring higher standby-mode efficiency from power supplies. It's pretty easy to make an SMPS draw minimal current when plugged-in but not in use. But it's difficult for a transformer-based supply due to the unloaded losses present in the transformer even when there is no connection. There is also the issue of poor conversion efficiency compared to SMPS.

We have tested two classes of linear supplies with good results:
There is a group of people who care about quiet power supplies for their digital devices: the audiophile community. And for this purpose there are transformer-based, 5V linear supplies available on Ebay and AliExpress. We have evaluated one of these units and it worked great. All have IEC 60320 C14-style AC input connectors so you can use a mains cord specific to your region.

Jan 2019 update:
We've had a couple reports of the supplies from Ebay above showing up DOA or unable to meet the Kiwi current requirement such that the Kiwi doesn't power up (even though the supply puts out 5V under no-load conditions). The supplies were replaced by the seller, but caveat emptor.. This one is a little expensive but the transformer can be strapped for 115 or 230 volts. It's an open-frame supply with all connections via solder lugs so you must add your own cables. Consider cutting off the cable with a 2.1mm circular connector from an old, crappy wall-mount supply you have lying around. For a line cord with a region-specific plug you can scavenge from old equipment or sacrifice a cheap extension cord (i.e. cut the receptacle end off and just use the plug and cable). Please add an inline fuse to your line cable (we did!) And insulate all line-voltage connections, particularly at the transformer. When dealing with line voltages please be careful, go slow, don't work alone and ask for help if you need it. We don't want any fatalities or injuries as a result of advice given here.

If you absolutely must use an SMPS then consider this one which we have found to be fairly quiet. It uses a standard IEC C14 input connector which means you can find an adapter cord that that matches the mains plug requirement of your country/region (C13 on the cord mates with the C14 on the power supply). For example, USA would need C13 to NEMA 5-15P, AUS/NZ C13 to AS/NZS 3112, etc.
  • Mean Well, 5V 3A, 2.1mm plug, 85 - 264 VAC IEC C14 input connector
  • Mean Well, 5V 4A, 2.1mm plug, 85 - 264 VAC IEC C14 input connector

Antenna advice

Many of the Kiwi beta sites use simple wire antennas (dipoles, verticals, etc.) with good results (although LF/VLF usually suffers unless an active antenna is used). As with noise reduction, experimentation with antennas is usually an incremental process. If you are new to antenna building then start with a simple random wire. You will hear something. Then you can try a more complex antenna and see how much improvement there is.

There are many commercial sources for E-field (whip, probe) and H-field (loop) active antennas. Here are some in no particular order: Clifton Laboratories is no longer in business (some products now sold by DX Engineering), but their Z1501D active antenna is legendary if you can find one.

There are a number of active antennas, both kits and pre-built, on Ebay. Most are based on the design of the PA0RDT Mini-Whip.

It is also not that difficult to construct your own. We're a fan of the designs from Chris Trask, N7ZWY, of Sonoran Radio Research: Complementary Push-Pull Amplifiers for Active Antennas

Articles about active antennas including advice about grounding of unbalanced (coax) and balanced feedlines:
The Seeed Bazaar sells relatively inexpensive SMA adapters: We used this inexpensive 3.3V GPS active antenna during our development and a similar one ships with the Kiwi "kit" version.

DX label editing

This section describes a panel accessible from an ordinary user connection that a Kiwi admin can use to make label changes. For an interface that's more suitable to making a large number of changes (and has other features) see the admin page DX tab.

The DX labels in the area above the frequency scale are editable by anyone who has admin privileges. Shift-clicking on a label will bring up a panel with the parameters you can edit. The admin password will be requested first if necessary. The Modify, Add and Delete buttons at the bottom make the changes. Using Add is how you can duplicate, starting with the information from an existing label, without changing the original label itself. Note: Changes from this panel cannot be made when any admin page connection is open due to database locking issues.

If you shift-click in a blank spot of the label area (i.e. not on top of a label) the panel is setup with the current frequency and mode. The type is set to the first entry in the Type menu but the other fields are left blank for you to edit. By default the first type is named active and makes the label cyan-colored. But you may have changed then names and colors of the Type menu entries via the admin page, DX tab.

If you alt/option-shift-click on a label its type is toggled between the first two values of the Type menu. This shortcut is meant to quickly change the type value without opening the full editing panel. This is useful for example with the two default Type menu entries of active (cyan) and watch-list (red). The Kiwi ships with a number of existing labels in red of type watch-list just to give you an idea of how you might customize your Kiwi's labels. When a signal is heard you can use the shortcut to switch the label to active. But you are free to define the labels and types however you wish.

If you are a Kiwi admin it is possible to edit the DX labels on a mobile device. Touch the label to select it. Then two-finger tap in the waterfall to show the popup menu. Tap the edit last selected dx label menu entry.

Details of fields in the panel:
  • Passband
    Enter a passband specification to override the default for the demod mode selected. You would do this to customize a label for a particular signal characteristic, e.g. a FAX signal in USB mode but needing a more restricted passband than the default for USB to get best reception.

    The passband notation used is simplified compared to other places such as in the frequency entry field. Use a single number to specify a symmetrical passband width for modes like AM, IQ etc. Use two numbers separated by a space or comma to specify an unsymmetrical passband ("lo", "hi" freq) for carrier offset modes like sideband or CW. Numbers are in Hz or can be kHz using the suffix "k" i.e. "3k" "2.7k" etc. So an especially wide USB passband might be "300, 3k" and a restrictive AM passband "3k". A USB passband example is "-3k, -300".

  • Type, and creating blocked (masked) frequencies/bands
    The different types simply select a color for the label to help differentiate them.

    There is one important exception. The last menu entry masked is used to create a blocked frequency or frequency range where no reception is possible (i.e. no audio is heard and no waterfall appears). This is useful when the Kiwi admin wants to prevent users from listening to certain frequencies/ranges possibly tying up channels for long periods of time (e.g. Skyking HFGCS EAM broadcasts, CB band). The passband area, either the default for the selected mode or the custom passband field, defines the masked frequency boundaries. To define a large masked band area see this Kiwi forum post.

  • Offset
    The offset field is used specifically for NDB band labels to create an offset in the displayed label position and the nominal carrier frequency. For example, an NDB with carrier on 276 kHz would have 276 entered in the label Freq field. But "-1050" (Hz) entered in the Offset field so the vertical line of the label appears on 274.95 which is where the LSB modulation of the NDB ident is located for this particular NDB. When the label is moused-over a small yellow triangle in the label area shows the 276 kHz carrier point. This mechanism is meant to help distinguish NDB carrier and ident frequencies when there are many overlapping label definitions -- typical for NDB DX'ers who add many labels to their Kiwis.

  • Ident
    The text inside the label is set from the ident field. A line break can be specified by using the HTML <br> sequence. From version v1.499 the newline sequence \n can also be used.

  • Notes
    The notes field text appears in a popup tooltip when the label is moused-over. From version v1.499 the newline sequence \n can be used to specify a line break (and also the HTML <br> sequence).

  • Extension
    Normally when a label is clicked only the frequency, passband and mode is changed (and possibly masking). With the "extension" field it is possible to start a Kiwi extension as well. Specify the extension name and parameters in the same way as if they were being specified in the browser URL (minus the "ext=" part). For example "s_meter" "wspr,40m".

    Labels that have an extension specified turn magenta when moused-over as opposed to the usual yellow. The extension is opened when the label is clicked (a shift-click opens that label in the edit panel as usual).

  • Schedule
    Optional schedule information can be entered specifying when the label signal might be heard (active). A label outside of its schedule period (inactive) is displayed in a lighter color with a dashed border (see the "FSK" label in the image above). But only if the panel checkbox filter by time/day-of-week is unchecked. Otherwise labels filtered by schedule are not visible at all to limit screen clutter. This feature is similar to the EiBi database which also contains schedule information and a filtering checkbox.

    On every 5 minute boundary (:00 :05 :10 etc) all labels automatically update so a label will transition between active/inactive etc with the appropriate change in appearance.

    The label is considered active if the current UTC day-of-week (DOW) button is selected (not greyed out) and the current UTC time is between the begin and end period. The default is active all the time (i.e. all DOW selected and UTC 0000 - 2400 which is displayed as blanks in the begin and end fields).

    There are a few considerations with this scheme. It's valid to specify a time period which crosses UTC midnight (2400/0000) and into the following day. Example: Time begin 2300 time end 0200, three hours later. If you wanted the label to only be active one day a week, on Wednesday, only leave the "W" DOW button selected. The software correctly compensates for the fact that the 0200 end time is on UTC Thursday. If you also specified the Thursday DOW the label would be active two days per week (Wed 2300-0200 and Thu 2300-0200), perhaps not what you want. Currently only one DOW/time entry per label is supported although the DOW days can be set arbitrarily and the time period applies to all of those days.

ADC overload

The top right of the S-meter shows a red "OV" indicator when ADC overflow/overload is detected. Tests with a signal generator show the ADC overflows when a single-tone exceeding -15 dBm (almost S9+60) appears on the antenna terminals.

If you're in Europe be careful about ADC overload in the early evening from the gigantic SWBC transmitters nearby. It can also occur from very strong local AM MW BCB signals. Use a smaller antenna or an inline attenuator if necessary. An attenuator can be as simple as a low-value potentiometer. Sure, the pot won't maintain a 50 ohm impedance like a proper Pi-network, but this is not critical. Adjust the pot until the overall waterfall noise floor drops to normal under high-signal conditions (roughly -100 to -130 dBFS shown on the spectrum display when fully zoomed in on a quiet frequency). Or until the "OV" indicator no longer shows.

One user cleverly notes that since the SMA and terminal block inputs are in parallel if you are connecting the antenna via the SMA connector you can place a swamping resistor or pot across the terminal block.

Martin, G8JNJ, has an excellent article on constructing simple series-tuned shunt filters to attenuate specific problem frequencies.

Our friends at are now selling an inexpensive broadcast AM block high-pass filter. Note the -3 dB point is 2.6 MHz so 160m will be attenuated in addition to LF/VLF.

One user has found some very inexpensive inline SMA attenuators on Ebay. At those prices you can afford to buy a range of values and connect them in series to get the optimum attenuation.

There are several forum topics giving details about the OV indicator and MW band attenuation ( here, here, and here) including excellent work by Jim, WA2ZKD.

The images below show severe overload from two extremely strong signals on 720 and 810 kHz (exceeding -20 dBm, S9+53) in the AM broadcast band from a Kiwi located in a major city. Note the harmonics of the BCB extending into HF and the raised noise floor from all the reciprocal mixing. Zooming you'll find mixing products every 9 or 10 kHz up and down the band from VLF to 30 MHz (9/10 depends on regional BCB station spacing). The existing antenna is necessary for adequate HF reception so some sort of BCB filtering will be necessary. Click on images for larger.

Noise reduction advice

Finding and reducing noise sources is an incremental process. We find it helpful to take a screenshot of the Kiwi waterfall before and after a particular noise reduction technique is tried. This will help you gauge how effective a fix is and even if a fix to one problem makes another worse.

E-field active antennas are compact and relatively easy to deploy, but are very sensitive to the local noise environment. Consider H-field loops and loopsticks as an alternative.
  • Experiment with different grounding configurations. At one location we found grounding the Kiwi to the apartment building CATV system coax outer braid made a huge improvement whereas grounding to the power mains safety ground was a disaster. At another location it was just the opposite. If possible try grounding to a dedicated ground rod.

  • Use a toroid choke for every cable connected to the Kiwi and Beagle. To get enough inductance, especially at LF/VLF, stack three toroids (Fair-Rite 5977002701, 23mm ID, 77 material) and tape them together. Then wind as many turns as possible from each cable through the cores. Hopefully 8-10 turns although this will be limited by the size of the connector on the end of the cable (if any). As you pass more and more turns through the cores the connector body will eventually not fit even though more wire turns would. We've also had reports that type 43 material toroids installed on the coax near the antenna offers good noise reduction.

  • Here's an excellent video by George, M1GEO, demonstrating the importance of mains filtering EMC & Shack Noise: Filtering the mains supply

  • See these articles for advice about grounding of unbalanced (coax) and balanced feedlines:

Mouser & Digi-Key free international shipping

Although they don't seem to advertise it, Mouser in the USA has free international shipping to many countries for orders over USD $50. So if you buy a Bel power supply and a bunch of toroids from them it can be very cost effective. We get free delivery to New Zealand in only 3-4 days. It's the best thing since sliced bread!

Digi-Key now offers the same deal.

Element14 / Embest BeagleBone

We need to mention a possible problem when using the Element14 BeagleBone with your KiwiSDR. When we first tried one about a year ago there was a very large increase (over +20 dB) in spurs and noise from the BeagleBone compared to using the original BeagleBone Black manufactured by CircuitCo or the BeagleBone Green manufactured by Seeed. We have spoken to others who had experienced similar issues trying to pass FCC certification of their cape while using the Element14 Beagle.

We tried another one more recently and there was absolutely no problem. It was just as quiet as the others. So perhaps this was just an issue with the components used in a particular early build or something. So just keep this in mind if you plan on using an older E14 you've had lying around for a while. We would have no hesitation in using one more recently manufactured.

Troubleshooting advice

  • The vast majority of problems are caused by voltage drop on the power supply cable. Please see Power supply advice.

  • If you purchased the Kiwi "kit" version (includes BeagleBone Green) do not install the supplied micro SD card into the Beagle for normal operation (like you would on a Raspberry Pi for example). The software is already installed on the on-board eMMC flash filesystem of the Beagle. The SD card is only used as a backup to restore the eMMC if something goes wrong. If you've started up the Kiwi with the backup SD install let it finish restoring the eMMC (lots of Beagle LED flashing) and wait for it to power down in about 4 to 5 minutes. Then remove the SD card and power up again. Everything should be working again.

  • Check board voltages and clocks using the Troubleshooting guide.

  • Possible reduced sensitivity latch-up when a strong transmitter operating nearby. Requires a power cycle to clear (unconfirmed, only one instance reported).

Getting the IP address (DHCP-assigned or static) from the LED pattern

Important: The pattern described below does not appear on the LEDs until about one minute after the Kiwi has restarted / rebooted. The pattern displayed prior is defined by the Debian OS and is documented elsewhere.

When the Kiwi software is running the four blue LEDs on the outer edge of the Beagle board (lower board of the two board stack) will display an encoded status message. Currently the message includes the IP address of the Beagle Ethernet interface and whether this address was set by a DHCP server or manually in the Kiwi configuration (network tab of the admin page).
IP address in this context means an IPv4 address (i.e. not IPv6).

The trick is to decode the message from the pattern displayed on the LEDs.

The structure of the message is as follows:
cylon-3x type cylon-2x content cylon-1x all-on-5-secs all-off-3-secs (repeat)

A cylon is a pattern where one lit LED travels quickly from left-to-right, and back again, either one, two or three times.

Type is a single digit (see below for digit definition)
'1' -- means content is an IP address set by DHCP server
'2' -- means content is an IP address set statically

If no IPv4 address has been assigned content will consist of 32 quick flashes of all LEDs.
This might happen if the DHCP server is slow (or failing) to set the IP address of the Kiwi or there is a problem with the configured static ip.

If the network uses only IPv6 addresses (i.e. not dual IPv4/IPv6) then content will consist of 16 quick flashes of all LEDs because display of IPv6 addresses is not supported.

An IP address is displayed as follows:
<3rd-digit> digit-sep <2nd-digit> digit-sep <1st-digit> num-sep

This is repeated four times to give a complete 12-digit IP address ABC.ABC.ABC.ABC,
where ABC are the 3rd, 2nd and 1st digits respectively, and digit-sep appears between each pair of digits and a num-sep appears where the dots ('.') are between the 3-digit numbers. IP numbers are always 3-digits and left padded with zeros if necessary, e.g. is displayed as

Definition of LED patterns:

Digits are displayed in binary with the exception of zero which is displayed with
all four LEDs on. In the following * means LED on, - means LED off.

'0'   * * * *
'1'   - - - *
'2'   - - * -
'3'   - - * *
'4'   - * - -
'5'   - * - *
'6'   - * * -
'7'   - * * *
'8'   * - - -
'9'   * - - *

I.e. the values of the LEDs are the usual binary 8-4-2-1 code when read left-to-right with the left LED (value=8) toward the outside edge of the Beagle. Each digit is displayed for 3 seconds. If you are not good at sight-reading binary values this should give you time to write the LED pattern down. You might have to observe several repeats of the message in order to catch (or confirm) all the digits.

The digit-sep (digit separator) is two quick flashes of all the LEDs.

The num-sep (number separator) is six quick flashes of all the LEDs.

At the end of the message, after the cylon-1x, all the LEDs are lit for 5 seconds then are dark for 3 seconds. Then the message repeats beginning with the cylon-3x pattern.

Kiwi user interface

Here are some aspects of the user interface that are not immediately obvious. In the descriptions below option/alt refers to the keyboard key usually marked "option" and/or "alt". Control refers to the key marked "ctrl" or "control". The "windows" key on Windows keyboards and the "command" key on Macs are not used. The "fn" (function) key is not used.

Clicking refers to left mouse button clicking. Right button or scroll-wheel clicking is specifically called out in the text to distinguish from ordinary clicking. We don't yet handle mice that have been configured for lefthand use where the button assignments are reversed (i.e. the right button functions as the left button normally would).

All of these shortcut choices need to eventually be customizable by each user.

  • Mobile device (touchscreen) differences
    Some touchscreen gestures are recognized:

    • A two-finger tap will show the popup menu that on desktop appears when you

    • A two-finger pinch motion (either pinch together or apart) will zoom the waterfall/spectrum in or out about the passband.

    • On very small screens various parts of the display will not be shown by default (e.g. top bar, dx label bar). Push the "Off" button on the main control panel repeatedly to toggle the display of these elements.

    • If you are a Kiwi admin it is possible to edit the DX labels on a mobile device. Touch the label to select it. Then two-finger tap in the waterfall to show the popup menu. Tap the edit last selected dx label menu entry.

  • Passband adjustments
    The passband is the yellow line drawn above the frequency scale. It represents the frequencies passed by audio filtering. It is most easily seen when fully zoomed-in. The yellow vertical line represents the carrier ("zero" Hz) point. You can click-drag various parts of the passband to adjust it. When the cursor is over different parts of the passband a tooltip will appear showing various parameters of the passband (see below).

    You can also change the passband in two other ways. By typing a passband specifier directly into the frequency entry field or by including a passband specifier as part of the URL tuning parameter.

    • Smooth tuning
      Click-drag in the horizontal area of the passband to smoothly tune the received frequency. The center frequency of the passband is displayed.

    • High-cut / low-cut filter adjustment
      Click-drag with the cursor over the sloped ends of the passband to individually adjust the filter high or low frequency cutoff. The cutoff frequency and filter bandwidth are displayed.

    • Filter width adjustment
      Option/alt-click-drag with the cursor over the sloped ends of the passband to adjust the filter high or low frequency together, effectively adjusting the filter width about its current center frequency point.

      Shift-click the zoom in/out icons (magnifying glasses) to also adjust the passband width around the center frequency. Each click widens or narrows the passband by 80% of its previous value. This is the equivalent of using the 'p' and 'P' shortcut keys described below.

    • Passband shift (aka passband tuning)
      Shift-click-drag anywhere in the passband to shift its center frequency without changing its width. The carrier (BFO) point remains unchanged.

    • BFO tuning
      Shift-click-drag with the cursor over the vertical carrier line to change the BFO (carrier point) while leaving the passband unchanged. As a comparison note that regular tuning = passband shift and BFO tuning done simultaneously. The carrier frequency is displayed.

    • Passband parameters sticky across mode changes
      Adjustments to the passband are unique to each mode and are remembered when the mode is changed.

    • Restore default passband settings
      To restore the default passband settings for a mode hold down the shift key before the mode button is pressed. A tooltip will appear reminding you the passband will be restored. New Typing "/" alone in the frequency entry box will restore the passband to the default value for the current mode.

  • Keyboard & mouse shortcuts
    • General keyboard shortcuts
      Many keyboard keys are assigned shortcut functions. Type the 'h' or '?' keys to popup a list of all shortcuts. You can dismiss this popup with the escape key or by clicking the 'X' at the top right.

    • Rounded frequency set (shift-click in waterfall or frequency scale)
      Instead of being set to the waterfall frequency directly under the cursor, the frequency is set to the nearest rounded value that depends on the band and mode. In this way you only have to shift-click close by to the even frequency your signal is likely to be transmitting on. The value is 9 or 10 kHz in the LW or MW band depending on the setting of the 9/10 step button. 5 kHz in the SWBC bands and 1 kHz everywhere else.

    • SWBC database lookup (control-shift-click in waterfall)
      The waterfall frequency under the cursor, rounded up or down to the nearest 5 kHz, is looked up on and displayed in a new window/tab. In the LW and MW bands the lookup is done using the database. On the NDB band the RWW database is used.

    • Utility database lookup (option/alt-shift-click in waterfall)
      The waterfall frequency under the cursor, rounded down to the nearest 100 Hz, is looked up on and displayed in a new window/tab.

    • Page down (control-click in waterfall or frequency scale)
      Shifts the waterfall down in frequency. Same as control panel left-arrow icon.

    • Page up (option/alt-click in waterfall or frequency scale)
      Shifts the waterfall up in frequency. Same as control panel right-arrow icon.

    • Mouse wheel zoom
      The mouse wheel performs zooming.

  • Saved session parameters
    The following parameters from the current session are saved in browser cookies and restored when you next connect:
    • Name/Callsign field
    • Frequency
    • Mode button
    • Zoom level
    • 9/10 kHz LW/MM band step button
    • Waterfall/Spectrum settings
    • Audio settings
    • AGC settings
    • Noise blanker/filter settings

    Because browser cookies are stored independently for each website these parameters will be stored independently for each KiwiSDR you visit.

  • International Beacon Project (IBP) label updates
    The labels displayed for the IBP signals on 14.100, 18.110, 21.150, 24.930 and 29.200 MHz automatically update every 10 seconds to show which world-wide beacon station is transmitting. The timing is taken from the KiwiSDR server and does not depend on the clock accuracy of your local computer that is running the browser. These beacon frequencies can be quickly selected under the beacon section of the select band menu. More information here about the NCDXF/IARU IBP system.

  • URL tuning and other parameters
    You can add parameters to the end of a Kiwi URL (web link). This is very handy especially with bookmarked URLs/links. Remember that the first URL parameter follows the
    '/?' characters and subsequent parameters are separated with the '&' character.
    E.g. mykiwi:8073/?f=...&ext=...

    parameter description
    f= set frequency with optional passband, mode and zoom
    pbw= or pb= set passband: width (carrier centered) or low,high
    pbc= set passband: center using current width or center,width
    ext= load extension including optional parameters
    mute mute audio
    vol= volume: 0 to 200
    sp or spec display spectrum using default filter
    sp= or spec= specify spectrum filter: iir, mma, ema, off
    spp= specify spectrum filter slider parameter unique to each filter
    peak enable spectrum peak hold mode
    wf= waterfall speed: 0, off, 1, 1hz, s, slow, m, med, f, fast
    wfm= waterfall min {,max} e.g. wfm=-110 or wfm=-90,-70
    wfts= waterfall timestamp: in seconds (2 to 3600)
    cmap= waterfall colormap: 0=default, 1..n=(others)
    sqrt= waterfall contrast: 0=default, 1, 2, 3, 4
    no_wf force open a no-waterfall / audio-FFT channel
    camp force open the audio camping/queueing page
    keys= sequence of keyboard shortcut keys to apply when connected
    user= or u= set "name/callsign" field
    pwd= or password= specify time limit / masked frequency exemption password
    p or prot or protected request a password protected channel
    winN open multiple windows/tabs with one URL/bookmark

    • Use the "f=" parameter to tune to a specific frequency when connecting instead of the last value saved in browser cookies. Use suffix M for a frequency in MHz.
      Additional parameters are specified after frequency. Examples:
      mykiwi/?f=14020 tune to 14200 kHz
      mykiwi/?f=7021.3cw 7021.3 kHz and cw mode
      mykiwi/?f=19.2cwnz11 19.2 kHz, cwn (narrow) and zoom (11)
      mykiwi/?f=10.1Mam 10.1 MHz (10100 kHz), am
      mykiwi/?f=1.4M/12000am 1.4 MHz, passband 12 kHz, am
      mykiwi/?f=4625/300,3300usb 4625 kHz, passband 300-3300 Hz, usb
      mykiwi/?f=100:400 pb 400 Hz center, current width
      mykiwi/?f=100:400,100 pb 400 Hz center, 100 Hz width
      Passband is /width or /low,high, or :pbc or :pbc,pbw all in Hz
      or use suffix k for kHz, e.g. /300,2.7k
      Use negative numbers for an LSB passband e.g. /-2.7k,-300 vs /300,2.7k for USB.
      Modes are: am, amn, lsb, usb, cw, cwn, nbfm, iq
      Zoom is 0 (max-out) to 14 (max-in)

    • The pbw= pb= and pbc= parameters duplicate the passband specifiers that can be given as part of the f= parameter. They are retained for backward compatibility.

    • Use "ext=extension-name[,extension-parameters]" to start an extension immediately after connecting, e.g.
      mykiwi/?ext=wspr,40m start WSPR extension on 40m band
      The extension-name can be any unique part of the names shown in the extension menu on the main page, e.g. iq for iq_display. The optional extension-parameters are specific to the extension. For WSPR the possible values are the bands: lf, mf, 160m, 80m_JA, 80m, 60m, 60m_EU, 40m, 30m, 20m, 17m, 15m, 12m and 10m.
      Use the help button at the upper right of each extension control panel for a
      complete list of all possible extension-parameters.

    • Use mute to initially mute the audio when connected, e.g.
      mykiwi/?ext=wspr,30m&mute start WSPR extension with audio muted

    • Use sp= to specify the spectrum filter algorithm:
      IIR Infinite Impulse Response
      MMA Modified Moving Average
      EMA Exponential Moving Average
      off No averaging applied

    • The shortcut keys that can be used from a keyboard can also be specified in the
      keys= URL parameter, e.g. keys=xyyys will cause the control panel to be hidden
      ('x' key), top and label bars to be hidden ('yyy' keys) and spectrum display to appear ('s' key).

    • Some Kiwis have connection time limits and/or masked reception frequencies. But the operator may also choose to setup an exemption password. You will be prompted for this password when a timeout occurs. But you can also specify it in the URL with the pwd= or password= parameter to prevent a timeout that might otherwise interrupt, for example, file recording. Specifying the exemption password in the URL will prevent the masked reception frequencies from being applied.

    • Some Kiwis are configured to have a mix of password protected channels and publicly available channels not requiring a password. If you want to connect and specify a password so as not to decrease the pool of public channels then give the p, prot or protected parameter in the URL. Note that if you are connecting from the same local network as the Kiwi, and admin auto-login has been setup, this is counted as a connection from the password protected pool and you do not need to specify this parameter.

    • To open multiple connections to multiple windows/tabs with a single link/bookmark use the winN notation, e.g.
      This opens 3 windows or tabs (depending on your browser configuration) with a muted 40m WSPR in the first, 10 MHz time station in the second and the S-meter extension running in the third using the last stored frequency/mode settings.

  • Frequency entry field
    In addition to entering the tuning frequency in the top left field of the Kiwi control panel (at the lower right of the screen) you can also enter a passband specifier. The format is the same as that described above for adding a passband to the f= URL parameter.
    Namely /width or /low,high, or :pbc or :pbc,pbw all in Hz.
    Or use suffix k for kHz, e.g. /300,2.7k to describe a typical USB passband.

    The passband can be given with or without a frequency. So to change the bandwidth alone to 7 kHz just type /7k or to tune to 5 MHz with a passband of 8 kHz type 5M/8k
    You can use this in combination with the mode-selecting shortcut keys to change mode, frequency and passband without ever touching the mouse.

    New Typing / alone will restore the passband to the default value for the current mode.

  • Frequency URL link
    To the left of the six +/- frequency step buttons is a green URL link icon. The intent is to provide a link you can copy and, for example, email to someone. That will allow them to tune to the same frequency, mode and zoom as what you are currently listening to. While hovering over the link right-click to bring up a menu from your browser and then select Copy Link (depends on your browser).

  • Right-click menu
    A right-click in the waterfall or frequency scale will bring up a Kiwi-specific menu.
    It includes some items that are also available with other (often hard to remember) key combinations such as the database lookup and passband restore functions. On a laptop there are usually options for generating a right-click if your trackpad doesn't have left/right buttons (i.e. with a two-finger tap, control-tap, etc.)

Frequently asked questions (FAQ)

FAQ — Setup
  • How do I know what IP address my Beagle is using?
    See the Network configuration section above for complete information.

  • Why can't I attach an HDMI monitor and USB keyboard to the Beagle?
    This is assuming you have purchased the Kiwi "board-only" and are using your own BeagleBone Black that has HDMI. The BeagleBone Green supplied with the Kiwi "kit" version does not have HDMI.

    The HDMI port, with a cable attached, is a significant source of interference to the SDR due to the fast edge rates of the signals. Ever wonder when you look at the BBB schematic why there are 47 pF caps on the (non-differential) data lines going to the HDMI framer chip on the Beagle? Edge rate control. No doubt for sufficient emissions margin.

    Also, by leaving the window system software off the Debian distribution on the micro-SD card, it installs on the Beagle in two minutes instead of twenty. For ordinary use you shouldn't have to make a terminal connection to the Beagle via SSH. You can just use the web-based configuration interface.

  • How can I protect the input against nearby transmitters and lightning-induced voltages?
    There is a forum post about the issue of front-end protection.

FAQ — Operation
  • What is the "Synchronous AM" (SAM) demodulation mode?
    As of software release v1.390 the Kiwi offers several versions of a synchronous AM detector for use with AM signals. The mode button toggles between a traditional double-sideband SAM detector and SAL and SAU which limit the passband to lower and upper sideband respectively. Use the keyboard shortcut 'A' to toggle the SAM modes.

    Sideband selection overrides the Kiwi passband, i.e. if you are in SAL mode then adjusting the Kiwi LSB passband lower limit works as expected. But adjusting the Kiwi USB passband is totally ignored by the SAL demodulator because it is filtering out the upper sideband.

    SAS offers a pseudo-stereo effect by routing SAL and SAU to the left and right ear exclusively. Note that SAS is a 2-channel mode like IQ so there is the same switching delay into and out of SAS as there is with IQ mode.

    While in SAM mode the PLL carrier offset is displayed at the bottom of the "Stats" tab on the main control panel. To demonstrate that the SAM PLL is working use SAM mode on an AM station tuned to the exact center frequency. The PLL carrier value should be a small value like +/- 10 Hz or so. Then click roughly 1 kHz lower in frequency on the waterfall. You should hear the PLL carrier tone sweep as it re-locks to the station carrier. The carrier value will now display the roughly 1 kHz offset value. When doing this the PLL will sometimes get unlocked. Especially if there is adjacent channel interference within the passband. To re-lock, tune to the station center frequency, switch to AM mode, then back to SAM.

  • How will KiwiSDRs participate in distributed applications?
    The exact mechanism used by an application that gathers data from many KiwiSDRs via custom code or FPGA changes is an open question. At the very least the configuration interface will allow an "opt-in" to whatever experiments are currently in progress. Your ideas are most welcome. Plenty of security implications too.

    Since this FAQ entry was first written we now have our first distributed application: the TDoA direction finding service. More information here about TDoA.

  • Why does the Kiwi interfere with my 2 meter radio reception?
    This is a known issue that is being investigated. There is a workaround. Please see this forum thread.

  • Why does the Kiwi stop working at my remote location that gets above 40 deg C?
    We've had a report of the Kiwi shutting down when running at a remote location location where the internal building temperature exceeded 40 deg C (104 deg F). The problem stopped when there was a modest airflow applied to the Kiwi even without lowering the temperature of the building. This might also be an issue if you place the Kiwi in your own enclosure (e.g. a metal one) without cooling holes. But we have not investigated this.

  • How can I receive DRM (Digital Radio Mondiale) broadcasts using the Kiwi?
    Two ways: Using the built-in DRM mode button and using an external DRM-capable program (e.g. Dream or SoDiRa) and Kiwi IQ mode together with virtual audio cable (VAC) software.

    First method: As of v1.360 the Kiwi has a built-in version of the Dream DRM decoder. See this forum thread for more information.

    Second method: Digital radio broadcasts on shortwave using the Digital Radio Mondiale (DRM) transmission format can now be received beginning with the Kiwi v1.140 release and using the external Dream application. The new IQ mode button to the right of the NBFM button is used. In this demodulation mode IQ format data is sent on the stereo audio output of the browser. A "virtual audio cable (VAC)" program can then be used on the host computer to route the browser audio to the input of the Dream program. See this forum thread for more information.

    You can find DRM transmissions in several ways. There is a published schedule although some of the stations listed do not appear to be active. You can also simply look on each HF broadcast band. A DRM transmission is easily distinguished in the waterfall from a regular AM signal due to the "flat" amplitude spectrum (see below RFI left vs HCJB right). Use the select band menu to step through each broadcast band looking for DRM signals. Of course different bands will be active depending on the time-of-day at the particular Kiwi you are listening to. Use the Kiwi day/night map to check conditions.

FAQ — Admin
  • How do I recover from a corrupted software build?
    If you think you might have a corrupted build of the software on the Beagle proceed as follows. Login over the network to the Beagle using the root account (there is no password). From a Linux machine use the SSH program, i.e. "ssh root@kiwisdr.local". From Windows try PuTTY or something similar. Then type these commands on the Beagle:
    • cdp (change directory project) This changes to the build directory.
    • up (update) This should fetch the latest software from, rebuild it, install it and restart the server.

  • Is there an automatic software update mechanism?
    Yes, the software checks for new versions on github and pulls updates from there. You can configure whether you want: no updates, update manually or update automatically in the background. Some users operate on networks with update policy restrictions.

  • How does access protection of the admin webpage work?
    Access control to the admin webpage and the SDR itself are handled on the Security tab of the admin webpage. By default there is no admin password set which causes attempted admin access from outside the local subnet (i.e. from the Internet) to be ignored. So by default you don't have to change anything, or assign a password, to be protected. If you don't want access by other users on your local subnet then set an admin password. But pick a good password because it can be used by anyone who has access to the Kiwi, including Internet users, to gain access to the admin webpage.

    If you are setting a password because you want to be able to administer the Kiwi from the Internet while, say, traveling, but you don't want the annoyance of having to give the password from your local subnet, then set the "Admin auto-login from local net even if password set?" option to yes. When you login with a password it is saved in a browser cookie, so this minimizes the number of times you must enter it.

FAQ — Publicly-accessible KiwiSDRs
  • Can I limit access to my KiwiSDR when connected to the Internet?
    Yes. There is a user password, separate from the admin password, used to control access to the main SDR webpage in case you want to limit access from Internet connections. You can also choose not to list your Kiwi on although we encourage you to do so.

    You can also divide the 4 channels into public and private sets. A setting on the control tab controls an inactivity time limit.

  • How much Internet upload bandwidth is used?
    Short answer: 40k bytes/second (320k bits/sec), all 4 channels active.

    The compressed audio takes 4.8k bytes/sec and compressed waterfall 12k at the current maximum frame rate (about 23 Hz). For 4 channels you might expect the total to be 68k (total multiplied by four) but it is only 40k bytes/sec because the waterfall slows down under the load of four simultaneous users.

  • What's the worst case daily and monthly bandwidth consumed?
    Short answer: 3.5 GB/day, 105 GB/month, all 4 channels active 24/7.

    This is simply the observed rate for all four channels active (40k bytes/sec) multiplied out to a daily and monthly value.

    There are plans to add a control mechanism to limit bandwidth consumption for users with capped Internet plans (e.g. 30GB/month). This would be done by throttling the waterfall update rate and/or maximum number of users evenly throughout the month, perhaps by having daily consumption targets.

FAQ — Design
  • Why are there only 4 channels? Can this be increased?
    Short answer: The digital downconversion (DDC) architecture used in the Kiwi only allows 4 channels of audio and waterfall before using up the resources of the FPGA and processing power of the Beagle. It's really an 8 channel DDC design since the waterfall is tunable independently of the audio.

    Update: As the Kiwi software has evolved different tradeoffs between number of channels, audio bandwidths and waterfall availability have been made. In addition to the standard 4-channel mode you can also configure an 8-channel mode at the expense of only two of the channels having the full spectrum analyzer style waterfall (the others get an audio FFT). There is also a 3-channel mode where the audio bandwidth is increased from 12 kHz to 20.25 kHz for higher fidelity listening.

    We've all been spoiled somewhat by WebSDR. We're used to the idea that modest SDR hardware (Sockrocks etc.) can support a dozen or more simultaneous connections. But the architecture and resources of those systems is very different from the Kiwi. The Kiwi is designed to be a completely self-contained, wideband (0-30 MHz), low-cost SDR not requiring any sort of external PC. In all cases with WebSDR a large part of a PC runs the FFT-based signal processing code. And the bandwidth covered by every WebSDR is relatively small: usually just a single band limited by soundcard bandwidth. The sole exception is the wideband Twente WebSDR which covers the same 0-30 MHz bandwidth as the Kiwi. But that system requires a very powerful PC with a c.a. US$1000 GPU card to process the multi-million point FFT required. It doesn't use a $39 BeagleBone Green. Sure, that system can support an astonishing 400+ simultaneous users, but you have to look at the tradeoffs. In exchange for full 0-30 MHz bandwidth on the Kiwi, at a relatively low cost, you only get 4 (8 really) DDC channels.

  • Why didn't you use a stacking-style header (cape) connector to the Beagle?
    Short answer: signal integrity, cost.
    You can always place the KiwiSDR as the outer board on a cape stack. Not using a stacking connector is a combination of factors.
    Signal integrity: The SPI runs at 48 MHz. A stacking connector potentially allows a "T" of signals lines to be constructed if the KiwiSDR is in the middle of the stack. Signal reflections due to the unknown termination characteristics of the outer board could cause problems.
    Cost: There is some additional cost for a stacking connector. It may seem small but every cost has been carefully considered to keep the overall board price low. Every user will end up paying for the stacking capability that few will use. It is also more difficult for the manufacturer to solder a stacking connector.

  • Why did you put a software-defined GPS on the board?
    This is a frequent question. The short answer is that it hardly cost anything to do so. It's was almost cheaper to add the GPS front-end than upgrade the ADC XO, requiring some source of frequency correction, to a more expensive VCTCXO. Also, having constructed a prototype of Andrew Holme's Homemade GPS Receiver and having so much fun learning about the fundamentals of GPS signal processing, we wanted to offer a device you could purchase capable of running Andrew's code. There was room in our existing FPGA for the design and we ended up using parts of the GPS Verilog for the SDR (embedded processor, SPI interface).

  • Will running the GPS reveal my exact location?
    No. The only place the high-resolution coordinates computed by the SD-GPS are displayed is on the GPS status tab of the admin webpage. So if access to the admin webpage is properly protected the GPS location will not be available. The locations shown on the main Kiwi webpage and on the public listing sites are from other purely text parameters configured on the admin webpage. So they can be completely arbitrary and set to not reveal your exact location. In addition, the public listing sites dither the locations shown on their maps slightly to guarantee privacy.

    When a GPS solution has been computed a button will appear on the Public tab of the admin page allowing the location field to be filled-in as a convenience. You can subsequently edit this field to obscure the exact position. But the dithering described above done by the public listing sites will essentially do this for you.

  • On the GPS tab of the admin page what do all those entries mean?
    The page is divided into two sections. The upper has one line for each of the 12 channels of the GPS receiver. The lower has overall status information.

    Upper channel display:
    • acq — Shows which channel the acquisition process is working with.
    • PRN — Satellite identifier (from the transmitted pseudo-random number sequence)
    • SNR — Signal-to-noise-ratio at acquisition. Minimum of 16 to begin tracking.
    • eph age — Ephemeris age +/-hh:mm:ss. Normal value -4 to +4 hours.
    • hold — How many bits in the current frame, out of 300, have been decoded.
    • wdog — Watchdog that will timeout and free tracking channel if bits are not being decoded. Different timeout values depending on channel state.
    • err — U = tracking loop unlocked. P = parity error. S = position solution. A = alert flag. Momentary errors are not necessarily a bad thing.
    • subframe — Colored when GPS subframe correctly received. Blinks grey when updated. Subframes 1-3 required for position solution (and 4-5 for Galileo).
    • novfl — Number of holding register overflows (a debugging aid).
    • RSSI — Relative Signal Strength Indicator. Above 250-350 means sat actually present. Above 1000 is an excellent signal.

    Lower status display:
    • acq — Acquisition state: "yes" if acquiring new sats, "paused" if active SDR connections prevent acquisition of new sats due to CPU resource constraints.
    • tracking — Number of sats tracked and appearing in one of the 12 GPS channel slots.
    • good — Of the sats tracked then number of those that are considered good enough to compute a solution from (min 4 for a solution).
    • fixes — Total number of GPS position and time fixes computed.
    • f/min — Fixes per minute.
    • run — How long the GPS has been running (H:M:S).
    • TTFF — Time-To-First-Fix: how long it took to get the very first solution after startup.
    • UTC offset — Difference in seconds between GPS time (no leap seconds) and UTC.
    • ADC clock — The GPS-measured true frequency of the ADC clock (nom 66.666600 MHz) In parens after are the number of computed corrections.
    • lat, lon — GPS-computed latitude and longitude in decimal degrees.
    • alt — GPS-computed altitude in meters. This value varies and is not accurate.
    • map — Link to a map showning the GPS-computed location.

  • On the GPS tab of the admin page how can I tell if I have GPS reception?
    Your Kiwi is not receiving actual GPS signals unless the subframe field described above is showing colors other than grey. Also the fixes field in the lower display will have an incrementing number. The RSSI indicator is shown during the satellite acquisition phase even though there might not be an actual GPS signal present.

  • Why does the acquisition (acq) state sometimes say "paused"?
    The GPS process of searching (acquiring) new satellites is stopped when there are active SDR connections on the Kiwi. Existing sats will continue to be tracked (and timing solutions calculated) until they eventually drift out-of-range. This is because the acquisition process uses an expensive FFT which cannot run simultaneously when there are multiple SDR connections. The Beagle doesn't have enough CPU to do all this work and still meet the realtime deadlines.

  • Why doesn't the GPS seem very sensitive?
    To help meet the Kiwi price targets a very modest "puck"-style GPS active antenna with a short, but lossy, RG174 coax cable was used. The antenna works okay when placed outdoors with a clear view of the sky. But this is often difficult given the short 3 meter cable. Also, the open source software is not as sophisticated as modern commercial GPS receivers which have had years of software optimization to improve performance. The Ethernet cable can be up to 100m long, so consider placing the Kiwi itself in a location where the 3m GPS cable will reach. Or see below for suggestions about how to extend the GPS cable.

    Here is a forum thread detailing one user's experience in improving GPS reception.

  • I need to use a longer antenna cable. What to do?
    Extending the GPS cable must be done carefully so as not to increase the cable losses and reduce sensitivity even further. Do not extend the supplied antenna with additional RG174 coax as it has -1.5 dB/m loss at the GPS frequency (-4.5 dB for an additional 3m!) Instead use a length of lower loss cable: a short length of RG58, RG8 or LMR400.

    When the combination of the puck antenna and cable type/length restrictions doesn't give a sufficient signal at the Kiwi GPS input it may be necessary to use another antenna with better performance. See these excellent GPS antenna/cabling recommendations from FEL. An example of a better antenna (with N connector for RG8/LMR400) from Ebay.