[amsat-bb] Re: HF Satellite Experiment?

John Heath g7hia at btinternet.com
Tue Apr 19 10:14:03 PDT 2011

Hi Bob,

Congratulations, sounds like an interesting experiment. 
I will be listening for the transmissions.
Do you have estimated output power yet?
Will the cubesat TX in eclipse, less active ionoshere.
Will the beacon be on all the time, or intermittent.

73 John G7HIA

From: Bob Bruninga <bruninga at usna.edu>
To: amsat-bb at amsat.org
Sent: Tuesday, 19 April, 2011 14:22:52
Subject: [amsat-bb] HF Satellite Experiment?

Cubesat HF experiment:

We have revised our HF satellite experiment proposal to be a CW telemetry
beacon on 40, 20, 15 and 10 meter bands.  The experiment will last only a
few days, since the deployed 1000m tether will have so much drag, we will
de-orbit in only a few days.

The idea is a keyed CW oscillator on 7.010 MHz with harmonics on 14.020,
21.030 and 28.040 MHz.  These bands are all in the IARU Satelilte
allocation.  We will filter all harmonics above 28 MHz.  

The challenge will be how to feed a 1000m long wire from only a 4"x4"x7"
counterpoise (on all bands). transformer coupling?

The tether will be vertical and can act as a long wire antenna with a very
narrow cone angle pointed straight down.  Antenna gain will be more than 10
dB on all bands.  This moving donut gain pattern sweeping across the earth
should pose some interesting reception reports (If any of it gets through
the ionosphere).

Launch Opportunity no earlier than March 2012.  Putting us closer and closer
to the Solar Max which would be the worst time for this experiment.

Other than a nice AMSAT experiment, if anyone can use this for valid
ionosphereic science, come join us.


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