FM Interference to Linear Transponder Satellites

Alexandru Csete OZ9AEC has previously written about interference from FM stations on the HO-68 linear transponder. He now reports that other satellites with linear transponders (designed for SSB/CW use only) also suffer from local FM traffic by people who haven’t got a clue that they are transmitting in the satellite uplink segment of the 2 meter band (145.8-146.0 MHz).

This recording was made on Saturday, May 5, 2012 using the AMSAT-UK FUNcube Dongle and Gqrx SDR. It shows very strong FM transmissions on the FO-29 linear transponder which could be from Spain or Portugal. The topic appears to be chocolate. Alexandru says – If you know who these people are, be sure to send them a QSL card!

The use of FM on a linear transponder satellite reduces the lifetime of both the batteries and the transponder itself.

Watch FM on FO-29 amateur radio satellite

How to work the SSB amateur radio satellites

AMSAT-UK FUNcube Yahoo Group

FUNcube Group Membership Exceeds 2000

In under a year the AMSAT-UK FUNcube Yahoo Group has achieved over 2000 members.

The group was created by Rob Styles M0TFO at the end of October 2010 to provide support for the AMSAT-UK FUNcube satellite and the FUNcube Dongle (FCD) Software Defined Radio (SDR).

The FUNcube satellite project is an educational CubeSat project with the goal of enthusing and educating young people about radio, space, physics and electronics. It will support the educational Science, Technology, Engineering and Maths (STEM) initiatives and provide an additional resource for the RSGB GB4FUN Radio Communications Demonstration Module.

The target audience are school pupils in the 8-18 age range. As well as providing a strong 145 MHz telemetry beacon for the pupils to receive FUNcube will also have a 435/145 MHz linear transponder for Amateur Radio SSB/CW use.

The FCD SDR was originally developed for educational outreach as part of the ground segment for the FUNcube satellite. However, it was realised it can be used for many other applications as well, so AMSAT-UK developed a Pro version which has a frequency range of 64-1700 MHz.

Similar to a USB TV Dongle, the FCD simply fits into a computer USB port and can be used with freely available Software Defined Radio software. The FCD is all-mode which this means that as well as data, it will also receive many other signals including AM, FM, SSB and CW and weather satellite images.

Join the FUNcube Yahoo Group at

SDR-RADIO software

The FUNcube Dongle SDR can be ordered via

Information on the FUNcube satellite project is at

A sample edition of the AMSAT-UK newsletter OSCAR News can be seen at