[amsat-bb] Re: Delfi C3 first orbit

[Wouter Jan Ubbels]

Hi David,

you are totally right.
Indeed, Delfi-C3 will first exit eclipse over the US at 0501 UTC and this is
the chance to hear the spacecraft boot up and hear its very very first
signals. (The satellite has no battery so is not active in eclipse) So we
would like to ask hams especially around the Western US and Alaska to listen
to the spacecraft during that phase.

Telemetry downlink is on continuously, approx 1 frame every second. A sample
recording of the 1200bd BPSK AX.25 downlink can be heard at

http://www.delfic3.nl/photoblog/wp-content/uploads/2008/02/delfic3_sciencemode_tm.wav

If all goes as planned, the spacecraft should come up on the primary
downlink frequency of 145.870MHz broadcasting AX.25 telemetry, but please
also check the backup downlink at 145.930MHz (also AX.25, similar signal as
the primary freq) in case nothing is heard on the primary frequency. The
downlink is continuous, periods of no data are filled with flags, similar to
AO-16.
Keep in mind to tune for Doppler, and when using RASCAL, tune 1600Hz lower
in frequency when using USB mode in order to center the signal at 1600Hz.
(This also holds for those who set the freqs in a SATPC32 file) In any case,
tuning around slowly would probably be the best strategy, due to TLE
uncertainty and spacecraft transmitter frequency drift caused by temperature
variations.
The spacecraft will most likely be tumbling, especially during this phase,
so note that polarization fades might occur. It is advantageous to switch
polarization if you have the ability to do so.

If you hear Delfi-C3, please send reception reports to
missioncontrol at delfic3.nl and state the following items:
-your name / callsign
-your location (Maidenhead gridsquare or latitude / longitude)
-time of AOS & LOS (UTC)
-frequency
-signal strength
-equipment (antenna, receiver)
-please record a wav file if possible
-please decode telemetry if possible with the RASCAL software. If you use a
PSK TNC instead, please append a KISS (.kss) file

more info on spacecraft modes / freqs and latest TLE's can be found on our
Mission Operations Page at:

http://www.delfic3.nl/index.php?option=com_content&task=view&id=93&Itemid=122

RASCAL can be downloaded at:

http://www.delfic3.nl/index.php?option=com_content&task=view&id=94&Itemid=123

Also, if you have listened for the spacecraft but not heard signals, please
do report "nothing heard", since this still is valuable information to the
team.

thanks on behalf of the team, everything is good to go now!

Wouter Jan Ubbels PE4WJ



On Sun, Apr 27, 2008 at 1:58 AM, <G0MRF at aol.com> wrote:

> Hi all.
>
> Delfi C3 is being launched at 03.53 UTC on Monday.
>
> I've loaded the keps from the web site, and it looks like the first
>  stations
> to hear the satellite will be on the west coast of the USA at around
>  05.01
> when the satellite exits eclipse heading north. Can anyone confirm this
>  sounds
> about right?
>
> It doesn't look like the satellite will have a good pass over the
>  University
> ground station until around 4.5 hours after launch. All the more  reason
> to
> collect some valuable telemetry in the first few hours.
>
> Exciting times......
>
> David
>
>
>
>
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