[amsat-bb] Re: Charge for Satellite Tracking?

[Peter Guelzow]

Hi Graham,

this is very good news indeed and I'm excited to hear that you will use
it on FUNcube and UKcube..  the principals of ranging are easy to
understand and I think it would be an ideal educational tool to learn
about orbital mechanics, Kepler's law, etc., even how GPS works..  
argh... we could create our own GNSS system .. haha  :-)

The AMSAT ranging system developed by Karl Meinzer DJ4ZC and later
optimized by James Miller G3RUH was used on all Phase 3 satellites
(OSCAR-10/13/40). You only needed an 400 Bit/s BPSK demodulator (used
for telemetry already) and a BPSK modulator (as part of our command
station). With the Phase 3 satellites it was also working through the
regenerative ranging mode of the IHU, i.e. the Beacon TX data was
directly feed by the Command RX.  Like with the transponder, you have to
measure or calculate the system phase delays to calibrate it and achieve
higher accuracy. This includes calibrating your own system through a
simple "repeater"...  but even without calibration, it already works
amazingly well..

Most people will laugh today, but the early AMSAT ranging software was
running on the amazing ATARI 800 computer and Karl's IPS software.
Beside the P3 satellites, we used this also LEO like AO-21 and on FUJI
OSCAR-12 to provide early Elements for those satellites... it was fun!

73
Peter DB2OS



On 01.11.2011 10:03, g.shirville at btinternet.com wrote:
> Hi Peter,
>
> Many thanks for the link. On our FUNcube cubesat mission we are
> promoting, as one of the many educational outreach subjects, the
> opportunity for a group to design and build such a ranging system
> using the U/V linear transponder that we will be flying on board. The
> same functionality will also be available on UKube.
>
> Maybe others can use this idea to help justify the presence of amateur
> transponders on satellites to provide independent position
> information. We might, however, have to ask Jim to take down his paper
> from the web so as not to make it too easy:)
>
>
> best 73
>
> Graham
> G3VZV
>
> or just do it yourself....
>
> http://www.amsat.org/amsat/articles/g3ruh/123.html
>
> Sorry - I could not resist..    old AMSAT technology, almost forgotten
> by most people...
>
> 73s
> Peter DB2OS
>
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