Adding a KiwiSDR to the KFS SDR system

September 2019:

- I am planning to add a KiwiSDR to the KFS system. It will have a separate web address and get its radio signals from the TCI 530 omni antenna. For detailed capabilities of a KiwiSDR click here. A list of all KiwiSDR systems publicly available is at

- Alpha testing Would you like to help checkout the KiwiSDR sysem before I move it to Half Moon Bay? Send me an email if you have the time.

- Timing: Most of the materials are in hand; assembly checkout, are on-going. Installation at Half Moon Bay should be before the end of this year.

SDRs Compared


- Here is a comparison between the features of a KiwiSDR and a WebSDR:


1. The KiwiSDR is a general coverage HF receiver covering the entire HF spectrum - 10 kHz. to 30 Mhz., but is practically limited to 3 to 30 Mhz. by the TCI antenna at KFS.
2. The KiwiSDR is limited to four (4) users, so the inactivity timeout would have to be set short (30 minutes?).
3. The Kiwi uses a single wideband receiver with adequate sensitivity and fair overload protection.
4. The KiwiSDR has long latency - a delay of nearly two seconds. This makes use in a ham QSO inconvineint, at best
5. The KiwiSDR works with any browser that supports HTML5. Internet Explorer does not work.
6. Using with KiwiSDR with mobile devices, e.g., iPhone, is a compromise.
7. Extensions to the Kiwi allow demodulaton of cw, fax, fsk, Loran C, Navtex, SSTV, and WSPR - at the server. The user requires no additional hardware or software.
8. Other extensions include a beacon scanner and TDoA system, with possibly more to come.


1. The WebSDR is a ham-band only receiver system; it covers the entire 160, 80, 75, 40, and 20 meter amateur radio bands.
2. The WebSDR handles an almost unlimited number of users (capped at 90, currently) with an inactivity timeout of 120 minutes.
3. The KFS WebSDR uses eight separate high-quality narrow-band receiver modules with outstanding sensitivity and good overload protection.
4. The WebSDR has latency of the order of a few hundred milliseconds, so it is usable in a ham QSO.
5. The WebSDR works with Internet Explorer as well as HTML5 browsers.
6. WebSDR offers a specific web page for mobile devices.
7. Each user must add virtual audio cable and demod hardware/software for each digital mode desired.
8. Other capabilities require external hardware and/or software.


Locally, there are two KiwiSDR systems available for your checkout - Northern Utah - and - KPH -.

I would appreciate comments, ideas, and suggestions in regard to this upcoming addition to KFS. Please email me.

Craig, W6DRZ