High Altitude Ballooning

For a little while now I’ve been fascinated by the hobby of “High Altitude Ballooning“.
It’s such a short while that I can’t yet claim to be an expert in that subject, but what I have seen has really sparked my interest and imagination.

I stumbled on a page on the  "Raspberry Pi" web site, and it turned out that the "Pi" and ballooning have been bedfellows for quite a while.    Furthermore it seems that the BBC's James May (Man Lab) and Channel 5's Gadget Show  have have featured balloons, but as someone who rarely watches TV (even more rarely now Time Team has been axed!), this has only recently come to my attention.

This particular activity, and the background to it appears to pull together a number of disciplines, and it’s the amalgamation of these which has really got me excited.

Once I discovered, almost by chance that the telemetry transmitter from HABs (High Altitude Balloons) could be received at my modest radio station from a distance of 200+ miles I realised I could participate in this activity, even if I never actually went near a balloon.

Even more exciting was the realisation that many of the participants in this activity sre relatively young people.    I've long felt that it is high time that the younger element of our population took up the baton of technical innovation and put those of us of the “older generation” firmly in our place.

It’s not exclusively the dominion of the young, but there appear to be proportionally more of the younger generation taking part than say in “vanilla” Amateur Radio.

Great!

Here are a few web links to enlighten you further, if you are interested :-

UK High Altitude Society – www.ukhas.org.uk

SpaceNear Online Tracker (Google Maps based application) -  spacenear.us/tracker
Note that ballooning is popular on the Continent as well as in the UK, especially in Poland.

StratoDean – a fabulous blog maintained by participants from the Forest of Dean – www.stratodean.co.uk

Balloon flights tend to take place at weekends when the weather is favourable.  “Weather” doesn’t just mean what the weather is like at ground level, but also what the winds are doing in the stratosphere as these balloons usually achieve an altitude of over 30,000 metres (yes, 30km!), and the participants aren’t too keen on flight predictions which end in either the sea or in foreign countries!

 The above graph lifted from the spacenear.us online tracking application shows the flight profile of a recent flight and clearly shows what is likely to be achieved in terms of altitude and duration.

A flight in the south of England becomes audible to my station in the north of England once it gets to around 10km in altitude, and the telemetry  transmissions are generally decodable throughout this phase of the flight.

Telemetry is transmitted from the payload using small proprietary low power transmitters which happen to use part of the amateur "70cm" band, which is basically where we radio amateurs come in - many of us have high specification equipment and aerials capable of receiving these transmissions.   In my case I use my trusty Diamond dual band (2m/70cm) co-linear and my FunCubeDongle ProPlus SDR, see below.

The above picture is a composite (ie more than one image has been stitched together to make a single image) screen grab of  a “Spectrum Laboratory” screen and shows in graphical form the strength of the signal from the “Stratodean1″ flight from around 0945 UTC until about 11:30 UTC when the signal was finally lost as the payload descended under its parachute.  NOTE: The sudden “steps” in the display were caused by me adjusting my receiver to get the signal “centered” in the passband of the display, and were not caused by a problem with the payload telemetry transmitter!

Just to give you an idea of how remarkable radio transmission are above 10km, note that the transmitter power is 10mW, and the aerial on the payload is a simple ground plane affair made by using a length of stripped back coaxial cable and drinking straws!   See the StratoDean web site for more information about this and other technical details about the payload.

The screen grab below shows the flight profile for StratodeanOne and I've marked it up to highlight the part of the flight I was able to receive in Penrith (IO84 square).

Radio Prague - Another R.I.P., I'm Afraid ...

I don't really want to appear to be a "doom and gloom merchant", but a chance series of events caused me to learn that we (shortwave listeners) are about to lose another source of programming on shortwave, that of the very well known and respected "Radio Prague".

The sequence of events to which I refer started with the fitting of a 6kHz AM filter to one of my "classic" old transceivers, my FT-107M.

The filter was acquired from a fellow amateur who had acquired an FT-101ZD complete with said filter, but who wanted to return it to its "factory condition". For those not in the know, the FT-101ZD though equipped with AM facilities (a special board had to be acquired) had a rather lame implementation of this mode due to the way the "IF Shift" was connected (long story). The bottom line of this tale was that this particular FT-101ZD owner and myself eventually figured out what the previous owner had done and the modification was successfully undone, and the grateful new owner awarded me the unwanted AM filter as my reward!

This was a mutually acceptable arrangement, and today was the day I decided I would fit this filter to my FT-107M, as that particular radio implements the AM mode "properly".

The fitting of the filter to this radio was simplicity itself, and when it was done I decided to have a little tune around the 7MHz, or "41 metre" band looking for broadcast signals.

In early morning there is no shortage of strong signals from Europe, and before long I found myself listening to Radio Prague on 7.345MHz for the umpteenth time in my life.

As is usual these days shortly before the radio station closed down its English broadcast the announcer gave out some information about how to find Radio Prague on the Web (www.radio.cz), and a few minutes later I surfed into that very web site, like one does.

To my dismay my eyes alighted straight away onto a piece entitled "Radio Prague's shortwave broadcasting to end on January 31, 2011", the content of the article citing budget cuts as the reason why.

Now, the economics of shortwave broadcasting are a subject not unknown to me, as earlier in my life I worked in this medium, and was familiar enough with costs due to the fact that I actually signed cheques payable to the Regional Electricity Company who supplied the power to a major shortwave broadcasting station! Been there, done that, got the T-shirt ...

What I could never really relate to was the "value" in such broadcasting, as, being a Brit, I only ever was a "hobby" consumer of this medium. I was always told that overseas things were very different, and the average man-in-the street relied on shortwave to bring him news just as much, if not more so as he relied on his daily newspaper. I am sure this has been very true, but I wonder whether it is still true. I strongly suspect that it isn't, generally speaking, and, logically, many other broadcasting stations will soon be going the way of Radio Prague.

I would say, therefore, "enjoy them while you can" !