An update is well overdue, so here it is …
I needed a suitable radio receiver both to test that my radio transmitter was working OK, and to track the balloon during the flight. After a couple of abortive purchases I ended up with an AOR AR8000 which is a radio scanner with the rare (for a scanner) ability to listen to SSB transmissions (single sideband) which is what the balloon transmits. I bought mine on ebay for a good price because the battery compartment was listed as broken. When it arrived, the only thing wrong was a missing battery terminal. So I took one from a cheap battery holder, bent it to shape and fitted it. Sorted!
The capsule was next. These are almost always built from foam polystyrene which is very light and is an excellent insulator – vital when the outside temperature is -50C or below! I bought some sheets and a hot-wire cutter which gives good results after a bit of practice. I made the capsule from double-thick walls (50mm total), with removable base and lid. I then fitted the antenna to the base (using a grommet to allow it to retract when landing), and the GPS antenna and some other devices to the lid. The central part has cutouts for the two cameras.
With the antenna finished I wanted to test how far away I could receive the transmissions. So I set up the transmitter at home, and put the receiver and laptop in a car, placing a mag-mount antenna on the roof. The signal was easily received at 1 mile away and only stopped after I drove the other side of a small hill. I then swapped for a Yagi (TV style) antenna which still worked at 1.5 miles away. Not bad considering the transmitter power is tiny at 10mW (about 100’th of the power of your mobile phone). I’m confident the signal will be good over tens of miles with line-of-sight when it is airborne.
Helium gas is obviously an important item, and I ordered mine online for collection locally. Cylinders are rented out and you pay for the rental plus the helium and an adapter. The adapter is for piddly little balloons, not weather balloons, so I’ll have to adapt that a bit using a selection of hose, adapters, clips, glue, cable ties and duct tape!
Mrs Dave has been helping too, sewing up the parachute so it can be tied to the balloon. The parachute needs a central hole added for stability, including taped-up edges to stop it tearing. The main thing though is that it needs cords sewn in so it can dangle from the balloon above. The parachute in turn carries the payload below. This arrangement helps the parachute deploy after the balloon bursts, and it’s quite important that part of the flight works of course!
All UK weather balloon flights need permission from the CAA, so I applied to that in plenty of time. The CAA issue certification in the form of a NOTAM (Notice to Airmen) for the applied times and dates and location.
So now, with the balloon payload finished, helium cylinder in the garage, and NOTAM issued, only a few small (but important) things need doing – getting the camera and video ready, mounting the capsule to the parachute, that kind of thing. So, fingers crossed for the launch on Sunday!