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

Bruce Robertson ve9qrp at gmail.com
Mon Apr 28 16:17:54 PDT 2008

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

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

73, Bruce

>  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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