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Friday 13 September 2013

Birthday building... going to look at HAB

I had a bit of fun this morning before work as I have started to look at the code and electronics used for HAB. I have a couple Raspberry Pi (A &B), some licence free 433MHz FM and AM modules and a GPS thing that should connect to the Raspberry GPIO.

The CDARC guys years ago made a 2m 'Big Wheel' antenna and stacked two (with one offset 60 degrees from the other, so no nulls) for one of the VHF contests and I remember how good it was as an omni directional antenna horizon to horizon. I have a 5/8 co linear for 70cm too and I will mount both on a pole about 8m AGL.

A couple RTLSDR USB dongles (no HF converter) will do duty as RX and I have registered them with so I can track anything flying. I have a circuit for a small pre-amp using a MAR-4 MMIC on an SMT daughter board that I suspect will see use.

The 433.9MHz modules emit a signal (just connected a couple 1.5V batteries to one, at approx 433.92MHz. I think current HAB are using different frequency though.

I found this wonderful image of the North Norfolk coast taken from about 30km up by a camera on one of Dave Akerman's HAB flights and where the cloud is clear and you can see the coast it shows very nicely the beach site I like using for 80m/40m /P operation with the full square. It is just up from Kings Lynn

I have a couple of raspberry camera modules on order.

As I will work from home and the office will have the possible option of an operating bench I will take an old laptop that is 'spare' and probably not worth selling on ebay and add the two USB RTLSDR, SDR Sharp and Virtual Audio ports and create a static listening station. I note a few others appear around Cambridge from time to time.

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