[amsat-bb] Community Survey Request -- crosslinks, multi-hop packet, and satellite DX

Stefan Wagener wageners at gmail.com
Sun Apr 2 23:12:37 UTC 2017

A few quick thoughts:

1. Is the "long distance record" truly an academic goal? I hope that this
is just a side effect of a more scientific endeavour :-)
2. How will the deployment of the satellites being scheduled? Too close
together means long time for separation to make it useful but longer
lifetime for use. Too much initially separation and the satellites won't
see each other for too long.
3. How about the deployment altitude. The higher the better?
4. What happens to the sat in the middle, just a link between the other
ones and no direct contact/use?
5. How can the system be programmed that if one satellites fails it still
6. Why 1Us and not bigger for better power budget and redundancies?

Have fun,

73, Stefan VE4NSA

On Sun, Apr 2, 2017 at 5:54 PM, KO6TZ Bob <my.callsign at verizon.net> wrote:

> Zach,
> I like what I see so far on your initial proposal.
> In the past, I have been involved with 2-HOP and 3-HOP packet attempts
> using various combinations of the ISS, NO-44 and NO-84 when they were all
> working on 145.825MHz.
> Your proposal of using a 9K6 FSK 2-port_digi's on board three satellites
> in the same orbital track resolves what I believe to be the main challenges
> we faced in our 1200 baud experiment.  If the footprints overlap, the
> satellites should be able to talk to each other.
> 1)  Since the satellites were in different orbits, there was Doppler shift
> in the signal between them.  In your proposal, doppler is minimal for FM
> packet.
> 2)  With your 2-port digi, the repeated packets between satellites will
> not be interfered with by multiple up link signals. Improving the success
> rate.
> 3)  I find that 9K6_FSK is as easy to copy as 1200baud, so efficiency in
> channel usage is gained.
> Once the operators acquire confidence in establishing basic 2 & 3 Hop
> packet contacts, the other experiments and distance records you mentioned
> will follow.
> I'm in.....
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