[Ground-station] Balloon Launch - experiments?

[Phil Karn]

On 4/23/18 10:56, KENT BRITAIN wrote:
> A 5 to 26 GHz Vivaldi only weights 4.7 grams.
> 
> A 2-26 GHz Planar disk comes it at 1.9 grams
> 
> Minus coax of course.   Kent

Hard to beat that. Which would be cheaper and lighter: switching a
single radio across (say) four antennas, or just building four radios
into four antennas?

What's the radiation pattern?

If there's only one ground station, then you'd just activate the
appropriate antenna as the thing turns. Use an IMU to determine
orientation. If there's more than one ground station, then the
transmitter per antenna approach starts to look interesting. Could they
be driven to make a phase-coherent signal in space, or would it be
better if each transmitter carried an independent signal? Would they
have to be on different frequencies or would the antenna lobes not
overlap too much?

The transition glitches as the payload rotates could be very easily
handled with FEC and interleaving, something I'm very used to designing.

Phil
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