[Ground-station] Balloon Launch - experiments?

[Phil Karn]

On 4/22/18 20:11, Bruce Perens wrote:
> I have been using Odroid rather than Raspberry Pi cor just that reason.
> Pi has poor IO bandwidth.

The RPi 3+ has gigE, though the throughput is still limited by the
internal USB. So point definitely taken.
> 
> If frequency precision is why you'd like an oxco, would a ground beacon
> that is recorded provide enough?

Remember your environment up there. It goes down to -54C at the
tropopause before it levels out and starts to rise again in the mid
stratosphere due to shortwave UV heating of the ozone layer. The density
of the atmosphere at 32 km is only 1% that at the surface. Mechanical
shaking can be quite strong at times.

So yeah, a ground beacon or a GPS seems more practical than a local
oscillator, even a good one. A ground beacon will have doppler, so
you'll have to correct for it with the GPS.

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