[Noisebridge-discuss] Spacebridge launch planning meeting, Sunday 1/10, 5pm

[Joel Jaeggli]

Jonathan Lassoff wrote:
> Excerpts from Mikolaj Habryn's message of Wed Jan 06 18:44:18 -0800 2010:
>> I know nothing about radio :P how much power and weight would a
>> transmitter sized for 30 miles clear-air range require?  And it is
>> feasible to have a bidirectional link, or would it require being able
>> to orient an antenna on the balloon itself?
> 
> If you have line of sight (available for most of a balloon flight,
> except for landing/close to ground), you wont need much power with a
> directional antenna on the ground following where the balloon
> approximately is. It will probably take more power to transmit than
> receive.
> 
> The power source is probably going to be the biggest in terms of weight.
> Also, depending on how high up you are, you might need a heater or
> insulation to keep the cells warm enough to function.
> 
> I haven't looked at this kind of thing in ages, but I would think
> whatever's the lightest, lowest power radio (that you can use legally,
> ham radio, ISM, etc.) you can find should do.

aprs is typically done in 2 meter e.g. 144mhz, smallest handheld I've
seen is an alinco DJ-C7T/E (don't have one myself) which is about 100
grams with battery, less if you swap the rubber ducky for a wire whip
and power all the parts off the same battery.

with the previously mentioned tiny track 2 and a serial nema gps you're
basically done.

need a ham presentto run it, there seem to be a few around.

Joel KJ6DYU


> Closer down to the ground, maybe use the 3G in the *droid?
> 
> --j
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