ISS Packet Digipeater Back On 145.825 MHz FM

International Space Station – Image Credit NASA

ARISS is pleased to announce that Packet Radio from the International Space Station is back on 145.825 MHz FM.

A few months back, the ARISS Team did the foot work and paperwork to launch the final copy of the Ericsson VHF handheld radio to the ISS.  This work was began in October after the unit onboard the ISS failed.  ARISS has been using the Ericssons for 16 years. In the last days of February, the launch vehicle, SpaceX 10’s Dragon, flew to the ISS.  Then the ISS crew had the odious job of unloading and unpacking 5,500 pounds of cargo along with the Ericsson HT.

ARISS got word this morning that we now have VHF capability back in the Columbus module.  Followers of ISS Fan Club have already posted that they’ve heard and used packet, and are thrilled.

In 2015, ARISS began its first fundraising campaigns.  It relies on NASA, ARRL, AMSAT and individual donors, along with ARISS volunteers to pay the day-to-day operations expenses and everything related to the hardware, testing, and certification.  Donors can go to and to support the program.

EMike McCardel, AA8EM
Rotating Editor AMSAT News Service

Almost any 144 MHz FM rig will receive the ISS, you can even use a general coverage VHF scanner with an external antenna. As far as the antenna is concerned the simpler the better. A ¼ wave ground plane has a high angle of radiation and works well. Large 144 MHz colinears are not as good because the radiation pattern is concentrated at the horizon while the ISS is above 15 degrees elevation for most of a pass.

You can receive the ISS outdoors using a 144 MHz hand-held with its helical antenna but a 1/4 wave whip will give far better results.

In the UK we use narrow 2.5 kHz deviation FM but the ISS transmits using the wider 5 kHz deviation used in much of the world. Most rigs can be switched been wide and narrow deviation filters so select the wider deviation. Hand-held rigs all seem to have a single wide filter fitted as standard.

How to work the ISS using APRS Packet Radio

Amateur Satellites at Skills Night

Steve Hedgecock M0SHQ sending Packet Radio to the ISS

Steve Hedgecock M0SHQ sending Packet Radio to the ISS

The Chelmsford Amateur Radio Society Skills Nights, are hosted by the CARS Training Team and continue to be a popular and appealing event, especially for newcomers to the hobby.

There was an excellent turnout on the evening of Monday, June 15 with 68 people signing in.

A major highlight of this month’s event was a live demonstration of amateur APRS packet data on 145.825 MHz FM from the International Space Station (ISS) as its flew overhead. Steve Hedgecock M0SHQ had clear reception and even managed to get a few of his own packets sent and relayed by the ISS.

Andrew Garratt M0NRD in Newark-on-Trent was one of those who received Steve’s packets and he immediately sent an eQSL.

Steve had received his new Elk 2m/70cms Log Periodic satellite antenna from the AMSAT-UK shop just a few days before and it performed admirably. During the evening Steve explained how to get started with amateur satellites. They can be received on handheld rigs and worked using low power, just 5 or 10 watts. Further information can be found at

On May 31 Steve M0SHQ was filmed making contacts via the SO-50 satellite by the team from the TX Factor TV show so you may see him in one of their future videos.

Satellites were just one aspect of great evening, with a wide range of activities from home construction to how to operate portable taking place. Read the report on the evening at and

The next CARS Skills Night will be on Monday, July 20. It’s free to attend and all are welcome.

Space Station SSTV and Packet Radio via SUWS WebSDR

ISS SSTV and Packet Radio signals on the SUWS WebSDR

ISS SSTV and Packet Radio signals on the SUWS WebSDR

Martin Ehrenfried G8JNJ reports excellent SSTV and Packet Radio signals from the International Space Station (ISS) using the online SUWS WebSDR.

144 MHz prototype helix antenna

144 MHz prototype helix antenna

The omni-direction helix antennas at the WebSDR were designed with high elevation satellites in mind. Conventional antennas concentrate the radiation pattern towards the horizon resulting in weaker signals when a satellite is above 15 degrees elevation. Comparisons with other WebSDRs show the SUWS antennas provide a 6 to 10dB better signal to noise ratio on similar passes.

Martin says: “I had been experimenting with single turn ‘twisted halo’ design, and decided to try stacking them to see if I could achieve more gain. Modelling suggested that a stretched 3 turn helix with a helix circumference of approx 1/2 wave length and an overall length of 1/2 wave at 70cm, and fed with a gamma match at the centre would offer reasonable gain, an omni-directional pattern and mixed polarisation.”

You can use the free online SUWS Web Software Defined Radio from your PC or Laptop to receive the ISS and the many amateur radio satellites transmitting in the 144-146 MHz or 435-438 MHz bands. It also provides reception of High Altitude Balloons in the 434 MHz band and coverage of the microwave 10368-10370 MHz band.

The SUWS WebSDR is located at Farnham not far from London, 51.3 N 1.15 W, listen to it at

Full details of the antennas are available at

Brazilian radio amateur uses SUWS WebSDR to receive ISS SSTV

ISS SSTV image 9/12 received by Martin Ehrenfried G8JNJ using the SUWS WebSDR on Dec 18, 2014

ISS SSTV image 9/12 received by Martin Ehrenfried G8JNJ using the SUWS WebSDR on Dec 18, 2014

TNC-Pi Raspberry Pi Packet Radio Board

TNC-Pi kit built by Nick Bown 2E0CGW

TNC-Pi kit built by Nick Bown 2E0CGW

The TNC-Pi is a £22 ($40) KISS TNC board which is designed to connect to the GPIO port of the £25 ($35) Raspberry Pi computer board.

It provides a low cost means of using amateur radio AX.25 Packet Radio and APRS.

Nick Bown 2E0CGW has written a well illustrated review of the board. You can download the PDF from TNC-Pi by Nick Bown 2E0CGW

The TNC-Pi kit is available from

Australia’s own BLUEsat ready for launch

The BLUEsat Team - Image credit UNSW

The BLUEsat Team – Image credit UNSW

The University of New South Wales (UNSW) has declared its undergraduate student amateur radio satellite project BLUEsat is complete and ready to be launched into space.

As the official final green light came it was to have a stratospheric balloon test flight near Wagga Wagga in New South Wales. Talks continue on a space launch date.

BLUEsat satellite - Image credit UNSW

BLUEsat satellite – Image credit UNSW

BLUEsat, a 260mm cube weighing around 13 kilograms, will carry a flight computer with transmissions to include a beacon and amateur packet radio using the AX.25 protocol in a “mode J” VHF/UHF configuration.

Magnets will passively stabilise the satellite and align it with the Earth’s magnetic field, and it will be controlled via a dedicated communications groundstation VK2UNS at UNSW is equipped with a Yaesu FT-847 satellite transceiver.

It is hoped BLUEsat will be placed in circular orbit at an altitude of around 750 km that will take it over the poles. At this altitude, the satellite will travel around the Earth at a rate of around once every 90 minutes.

Once in orbit BLUEsat will be a digital amateur radio satellite, which means that voice and data files can be uploaded to it by any amateur radio operator in the world over which the satellite passes.

Students from UNSW will continue to be the primary operators of the satellite while it is in orbit and continue the educational focus throughout the full satellite lifecycle.

Through sponsors helping to pay the bills the student-led project has given a space experience that includes VK2UNS the ground control station.


Basic Low Earth Orbit UNSW Experimental Satellite (BLUEsat) project

January 2012 – Australian BLUEsat LEO undergoes tests

A Ham Radio AX.25 Open Source Soundcard Modem

Audio from AX.25 packet radio - Image credit Sivan Toledo 4X6IZ

Audio from AX.25 packet radio – Image credit Sivan Toledo 4X6IZ

AX.25 packet radio is currently the most popular data protocol for use in CubeSats.

Radio amateur Alejandro Santos LU4EXT is developing extmodem an open source APRS compatible AX.25 packet radio modem.

It is currently capable of both sending and receive packets at 1200 bps AFSK. The main feature of the software is that it is currently running three different demodulators in parallel, increasing the quality of reception. The first modem is Thomas Sailer HB9JNX / AE4WA‘s multimon, the other two are described by Sivan Toledo 4X6IZ in an article in the July/August 2012 issue of QEX.

Download extmodem for Windows from

QEX article – A High-Performance Sound-Card AX.25 Modem

APRS destination address for ham radio satellites

LU4EXT on Twitter