New webSDR for 144 MHz now online in Cornwall, England

There was interesting item on the Southgate Amateur News recently about a new web based software defined radio (WebSDR) based at Goonhilly in Cornwall, England. What is particularly interesting about this is that it covers 144 to 146 MHz.

From the Southgate Amateur Radio News website...

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144-146 MHz WebSDR at Goonhilly now available
AMSAT-UK and BATC have announced the availability of a new 144-146 MHz Web-based Software Defined Radio installation at Goonhilly 

This is being provided in collaboration with Goonhilly Earth Station where it is kindly hosted alongside the existing receiving equipment for the amateur radio transponders on the Qatar-Oscar-100 (QO-100 / Es’hail-2) geostationary satellite.

It shares the same Turnstile antenna that is used for the reception of the AO73, EO88 & JO97 CubeSats.

Being located in the far South West of the UK, it is anticipated the SDR will be useful for early Acquisition of Signal (AOS) of 144 MHz downlinks from amateur satellites and the International Space Station (ISS). Additionally it can be used for reception of tropospheric signals from the south – the Spanish beacon ED1ZAG on 144.403 MHz has been already been heard on the system.

The new 144 MHz band WebSDR is available at https://vhf-goonhilly.batc.org.uk/

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Even though the turnstile antenna is omni-directional with no gain, it's the location of this webSDR that makes it interesting. Here are just a few uses...

1) RSGB News service... I used it to listen to the weekly GB2RS news on the local GB3NC repeater on 145.725 MHz.

2) Sea Path... What's unique about this site is that it is effectively on a peninsula and has the sea on three sides. This allows more distant signals to be heard rather then say a WebSDR located in the middle of England.

During a quick scan, I could heard French SSB stations as well as repeaters which were at least 200kms distant.

3) Propagation Test... Anyone with a modest Yagi antenna and say 50 watts on 144 MHz may well expect to be heard up to 500 kms away under modest conditions. The map below shows a 500 km circle around Goonhilly.

Just make a transmission and see if you can hear yourself. It will allow you to check conditions as well as any antenna improvements to your station.

It can also be done of course on FM although the range would be much less.

500 km circle around Goonhilly

High altitude balloon over Cornwall heard on 434 MHz

There was a news item on Southgate Amateur Radio News recently about a balloon launch from the south of Cornwall. As it's about 200kms away from my location on the south coast of Ireland, it seemed as if it might be possible to hear the signals at 434 MHz.

I listened on 434.100 MHZ USB with my home made co-linear in the attic and sure enough, I could hear a very weak RTTY signal!

It took a while to get the FLDIGI software up and running properly as I haven't used it in many years and I was unfamiliar with the various settings. After much messing around, I got a decode like this...

*U$$1901,578,09:42:03,50.1436319,-5.4608369,29651,15,1.468*0A55

It looks like gibberish but there is data in there.

*U$$1901 seems to be the ID
578 seems to be the message number
09:42:03 is the time in UTC
50.1436319 is the latitude
-5.4608369 is the longitude
29651 is the altitude in metres
15 is the number of GPS satellites it is hearing
1.468 is the battery voltage
*0A55..?? Not sure what this is.Maybe a checksum?

As the balloon was gaining altitude, the frequency of the signal was getting lower gradually. I presume this was due to the colder temperatures? As soon as the balloon burst, the frequency went higher a lot quicker than it had gone lower on the way up. I presume this was due to the payload falling rapidly into lower warmer air before the parachute slowed it down.

As the map above shows, it was launched from Goonhilly, reached an altitude of about 37723 metres and eventually fell into the sea off the coast of Cornwall. Once the balloon was above roughly 10,000 metres, the 70cms RTTY was strong enough for me to get good decodes.

All the RTTY decodes are shown below.....