[amsat-bb] Re: Delfi C-3 tracking an keplerian elements

[Bruce Robertson]

On Mon, Apr 28, 2008 at 7:08 PM, Jens Kirsten <jens_kirsten at yahoo.de> wrote:
> Hi Dave,
>
>  for satellite tracking I use "orbitron". It's easy to use and freeware.
>  You can find it here: http://www.stoff.pl/
>  The Keplerian elements needed for tracking can be found on the Delfi C-3
>  web page:
>  http://www.delfic3.nl/index.php?option=com_content&task=view&id=93&Itemid=122
>
>  Simply copy and paste the 2-line format in a txt-file and save this file
>  as *.txt. This txt-file can then be loaded into the satellite tracking
>  program, for example "orbitron".
>
>  Don't worry about Az/El rotor. I could receive almost every cubesat on
>  VHF with my general groundplane antenna. Even with my HT TH-F7E
>  reception in the field is possible.
>
>  You can also download the RASCAL telemetry decoding software from the
>  Delfi C-3 page. See here:
>  http://www.delfic3.nl/index.php?option=com_content&task=view&id=94&Itemid=123
>
>
>  Best 73! from JO40ja
>  Jens - DL2FJK
>
>
I would add to Jen's helpful comments that your antenna choice
decisions are somewhat different when dealing with satellites. A
high-gain omni antenna for terrestrial use gets its gain by keeping
the radiation angle low. For a satellite, though, that means that you
will receive poorly above, say, 15 degrees, and that might be the part
of the pass where your omni antenna would otherwise have a fighting
chance.

All to say that a crummy 1/4 wave groundplane might work better than
the jpole, especially if you can tilt the vertical element over a bit
to reduce the null overhead.

This is truly an experimental branch of the hobby: each bird has its
different characteristics, and antenna design is great fun. Have as
many different options at hand as you can and see what works best for
you.

73, Bruce
VE9QRP


>  D. Mynatt wrote:
>  > Group,
>  >
>  > I'm new to this and a local ham has agreed to help me build a 'J'-type
>  > antenna matched to 145.930Mhz to track Delfi. I won't have a Az/El
>  > rotor setup, but my apt is the highest in the city (ain't saying much
>  > about CO, huh?) and I'm hoping that's enough as the antenna is good on
>  > the sides but not on the overhead, as I understand him to say.
>  >
>  > Any way, so I don't appear toooooo stupid can you tell me what
>  > application I'd use to know where this bird is at, when. How does the
>  > Keps for Delfi get into the app. Is everyone using SatPC ?
>  >
>  > Thanks for taking time outta this exciting moment,
>  >
>  > Dave (KA0SWT)
>  >
>  >
>
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