[Ground-station] Balloon Launch - experiments?

[Robert McGwier]

Agree with Phil

On Mon, Apr 23, 2018, 12:40 PM Phil Karn via Ground-Station
<ground-station at lists.openresearch.institute> wrote:

> On 4/23/18 08:45, Michelle Thompson wrote:
>
> > There are some ambitious ideas for matching linear polarization
> > (automated closed loop) for something that is tumbling around like a
> > balloon payload probably would. Don't rule it out just because it sounds
> > hard. We live in a golden age.
>
> Balloon payloads do swing in pitch and yaw, but not that much.
>
> cos(x) ~ 1 for small x.
>
> The real problem is that the yaw is completely uncontrolled and can
> change rapidly. Controlling this yaw is possible but difficult (I've
> been thinking about it for a while). But simple knowledge of yaw might
> suffice and would be much easier -- use an IMU with AHRS software.
>
> This will require an omni antenna (with low gain), a steerable gain
> antenna, or a set of directional antennas fixed to the payload and
> selected electrically.
>
> In the second category, the Qualcomm Omnitracs taco-shell antenna might
> be a very workable design. The requirements are very similar:
> azimuth-only control would be adequate, especially with a fan beam wide
> in elevation. Vertical polarization would be fine. If a surplus
> Omnitracs antenna could be modified, that would be ideal. Otherwise, the
> rotating reflector could probably be 3D printed.
>
> If an Omnitracs antenna could be modified for the payload, one could
> also be used on the ground. The only drawback here is a wide fan beam in
> elevation.
>
> Phil
>
>
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