[Ground-station] Balloon Launch - experiments?

[Michelle Thompson]

Five and Dime is where we're at.

5GHz up and 10GHz down. We have aspirations to move up, but our bread and
butter is 5 and 10.

-Michelle W5NYV

"Potestatem obscuri lateris nescis."


On Mon, Apr 23, 2018 at 9:53 AM, KENT BRITAIN <wa5vjb at flash.net> wrote:

> The PCB 'Big Wheel' antennas are veterans of many balloon flights.
>
> At the horizon they are linear horiz polarization.  But off axis they are
> elliptically polarized.  What band are you planning to use?
>
>
> ------------------------------
> *From:* Phil Karn <karn at ka9q.net>
> *To:* Michelle Thompson <mountain.michelle at gmail.com>; Zach Leffke <
> zleffke at vt.edu>
> *Cc:* KENT BRITAIN <wa5vjb at flash.net>; "ground-station at lists.openresearch.institute"
> <ground-station at lists.openresearch.institute>
> *Sent:* Monday, April 23, 2018 11:40 AM
> *Subject:* Re: [Ground-station] Balloon Launch - experiments?
>
> 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
>
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openresearch.institute/pipermail/ground-station-openresearch.institute/attachments/20180423/c4ac4fb9/attachment.html>