UBSEDS21 Balloon To Test 145.825 MHz APRS

UBSEDS18 Solar Powered Balloon

UBSEDS18 Solar Powered Balloon

On Sunday, December 11 Bristol SEDS students launched UBSEDS21 a 434 MHz Contestia and 144/145 MHz APRS solar powered balloon that may travel around the world.

Update Dec 23: UBSEDS21 over Spain having completed its first circumnavigation of the globe see track.

Update Dec 20: APRS creator Bob Bruninga WB4APR reports receiving @bristolseds UBSEDS21 balloon AD6AM-13 145.825 MHz Dec 20 1420 EST – Bob was Mobile in Annapolis MD.

Update Dec 18: UBSEDS21 has crossed the Pacific and reached Canada.

The UBSEDS21 balloon was built from 50 micron thick PA-EVOH-PE multilayer film and is about 1.9 meters in diameter, the payload weight was 34.2 grams.

After launch on December 11, 2016 the balloon achieved a stable altitude of 15.2 km flying in an easterly direction on its potential circumnavigation of the globe.

The initial plan was to use UBSEDS21 to contact the International Space Station (ISS) via APRS on 145.825 MHz. However, the VHF radio on the ISS is out of order, so this flight is used to test the amplifier and hopefully talk to any APRS enabled satellites.

The winter launch means the payload needs to deal with the sun staying low above the horizon during the day. For this reason, sideways facing solar panels were used.

Original post Dec 9:

Another pico launch from Bristol this Sunday, December 11 between 0500 and 0530 GMT. This launch is using a 1.9m envelope and longer payload train, and so we have a NOTAM in place. The flight is predicted to head south-east towards France.

The payload will be transmitting Contestia 16/1000 on 434.610 MHz USB. Each transmission of Contestia 16/1000 will be preceded by 10 seconds of pips and RSID.

The Contestia transmission rate will be once every 30 seconds during launch and when power is available during the day. Otherwise the transmission rate will be once every 2 minutes. Hopefully the tracker will operate from dawn to dusk, and maybe also during the night.

The tracker will transmit APRS outside countries where the amateur license is not permitted airborne (like the UK). Additionally it will test APRS on 145.825 MHz, with an output power of +26 dBm (400 mW).

More details will appear on the website

Many Thanks,

Richard Meadows M0SBU
Bristol SEDS

High Altitude Balloon tracking and information links

Richard M0SBU took the amateur radio training courses run by the Chelmsford Amateur Radio Society (CARS) at Danbury in Essex. Further information on the courses is available from the CARS Training Coordinator, Christopher G0IPU
Tel: 07908-107951
Email: training2017 at

What is Amateur Radio?
Find an amateur radio training course near you

IARU Paper: APRS Harmonization and removal of OSCAR sub-band

IARU_Region_1_logoIARU Region 1 has released the papers for the Interim Meeting to be held in Vienna April 15-17, 2016.

Among the papers for the C5 VHF/UHF/Microwave Committee is one on harmonizing APRS.

VIE16_C5_41_1.pdf – 144 /435 MHz APRS Harmonisation

The paper covers global band planning considerations and among the recommendations says:

Emphasise that spaceborne APRS must be confined to globally coordinated amateur satellite sub bands. Therefore items that are ambiguous and generate confusion in national band plans such as ‘Space communications’ and ‘New Oscar Sub band’ should be removed as soon as possible in all Regions in accordance with IARU-AC and Satellite Coordination guidance

It is believed that ‘New Oscar Sub band’ refers to the USA’s ARRL 144 MHz band plan and ‘Space communications’  to the Australian WIA 144 MHz band plan. These band plans, as well as those for some other countries, show 144.300 – 144.500 MHz as being for Amateur Satellite use.

Direct link for C5 VHF/UHF/Microwave Papers

Links for all committee papers and email addresses of Committee Chairs are at
[Although URL says 2017 the meeting is 2016]

ARRL 144 MHz Band Plan

WIA 144 MHz Band Plan

LAPAN-A2 Launch



An Indonesian satellite LAPAN-A2/ORARI, carrying an FM transponder and an APRS digipeater, is planned to launch September 28, 2015 on India’s PSLV-C30 rocket.

The satellite will be deployed in a 650 km near equatorial orbit with an inclination of between 6 and 8 degrees enabling it to cross the territory of Indonesia 14 times a day. The low inclination orbit means it will not be receivable in the UK.

The primary aims of the mission are Earth observation using an RGB camera and maritime traffic monitoring using AIS, both using frequencies outside the Amateur Satellite Service.

The IARU has coordinated these frequencies for LAPA-A2/ORARI:
• 437.425 MHz telemetry beacon
• 435.880 MHz FM uplink
• 145.880 MHz FM downlink (5 watts)
• 145.825 APRS digipeater (5 watts)

A recording of the telemetry signal can be heard at

LAPAN-A2 paper

AMSAT-ID Facebook Group

Organisasi Amatir Radio Indonesia (ORARI) in Google English

The IARU Region 3 Conference takes place in Bali, Indonesia, October 12-16, 2015

Do not Digipeat via PCSAT

US Naval Academy PCSAT

US Naval Academy PCSAT

As has been reported in the RSGB News, the PCSAT spacecraft was launched September 30, 2001 and has, due to an on-board power system issue, started to transmit APRS again on 144.390 MHz.

Although this is the correct frequency for APRS operation in IARU Region 2, it is not compatible with our Region 1 bandplan which has this part of the band designated for weak signal and particularly Meteor Scatter operation.

The orbit of this spacecraft means that sometimes it is in full sunlight and, at other times, it is eclipsed for a major percentage of the orbit. As the on-board batteries have lost their ability to hold a charge, the problem can only occur when it is in sunlight.

Various methods of mitigate this problem are presently under active consideration but in the meantime it is important that no amateur in Region 1 should attempt to digipeat through this spacecraft. Additionally those amateurs on the east coast of the American continent are also requested not to attempt to activate the spacecraft when it can be “seen” from Europe.

At IARU level, further work is being undertaken to reduce the risk from future spacecraft potentially causing similar problems. Such problems could result from developers not following the globally agreed bandplans for amateur satellite operations. In particular the IARU Satellite Coordinator has been requested to make urgent contact with the team responsible for XW-2(CAS-3) mission of nine satellites from China. Some of the proposed frequencies do not respect the internationally agreed Region 1 Bandplan for 2 metres.

Interference from PC-Sat reported July 28, 2002

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.

PSAT PSK31 CubeSat Update May 24

PSAT PSK31 FM Downlink received by Martin G8JNJ at 1429 UT May 22, 2015 using the online SUWS WebSDR

PSAT PSK31 FM Downlink received by Martin G8JNJ at 1429 UT May 22, 2015 using the online SUWS WebSDR

Bob Bruninga WB4APR released this update on the PSAT PSK31 CubeSat on Sunday, May 24

28 MHz PSK31 Receiver Board Flight Prototype - Brno University of Technology

28 MHz PSK31 Receiver Board Flight Prototype – Brno University of Technology

The PSAT PSK31 435.350 MHz FM downlink is full quieting with 6 bars using a decent UHF Yagi. But we have not seen any users other than those using the 28.120 PSK channel on HF normally. We welcome people to experiment with it.

Everyone within the 28.120 to 28.123 MHz ten meter passband will be uplinked and heard on the 435.350 MHz downlink.

The Naval Academy’s PSAT seems healthy with plenty of power (we are keeping the APRS digipeater off to allow max power for PSK31).

PSAT’s radio and packet system are a simple $250 APRS tracker sent to space. The PSK31 transponder is a single 3.4″ square circuit board made by Brno Universtiy in the Czech Republic. The CPU for controlling bulletins and timing is a simple Parallax Basic Stamp.

PSAT is actually only about a 1U cubesat but in a 1.5U package since the flight was available and it gave us more power for our NON-SPACE solar cells. We are using standard silicon that are only half as efficient as multi-junction cells, but only cost 1% as much.

PSAT has a single 21″ VHF  and 72″ long HF whip. It has two UHF 6″ orthogonal monopoles, all of very thin Nitinol wire.

More details will eventually follow as the page will be updated over the coming weeks

* PSAT packet telemetry is OK, Digipeater will be off (secondary mission)
* PSAT PSK31 transponder is ON with 28.120 MHz uplink! (primary mission)
* WOD data fixed.  Spin data now available.  Right now it is at 3 RPM with
+Z pointing 45 deg off Sun
* Launch TLE elements (below) are still very good
* http://PCSAT.APRS.ORG web page is now capturing PSAT telelmetry that
users inject into the APRS-IS
* BRICSAT telemetry has been heard but is cycling OFF due to low power
* BRICSAT PSK31 downlink (also FM) has also been heard barely (when ON)
* USS Langley not heard


PSAT: 145.825 – 1200 baud AX.25 telemetry – digi off
PSAT PSK31-5: 435.350 FM down, 28.120 SSB PK31 uplink – Brno University Transponder

BRICsat: 437.975 – 9600 baud telemetry evry 20s
BRICsat PSK31-6 – same as PSAT but PSK TLM on 375 Hz (PSAT on 315 Hz)

USS Langley – 437.475  9600 baud telemetry  <== CORRECTION

1 99993U          15140.67013889  .00040043  00000-0  10235-2 0 00009
2 99993 055.0004 339.9238 0251027 182.3314 074.3075 15.12517086000014


Guide to using the PSK31 transponder

ParkinsonSAT (PSAT)

Fldigi PSK31 software

Listen to satellite signals in the 145 and 435-438 MHz bands from anywhere in the world using the online SUWS WebSDR located near London. Further details at

Yahoo Group