[amsat-bb] Re: Portable satellite antenna
pisymbol at gmail.com
Thu May 5 06:20:38 PDT 2011
On Thu, May 5, 2011 at 8:06 AM, Bob Bruninga <bruninga at usna.edu> wrote:
>> The issue is an antenna. I live in an antenna
>> restricted area so I am not sure what to do.
>> My goal is to work minimally the ISS! :-)
>> I own a Kenwood TH-D72A
> Walk outside during a pass. Have the radio configured and working for
> normal APRS. Then just change from 144.39 (APRS) to 145.825 and you should
> see everything from the ISS. No need for anything other than the rubber
> duck antenna.
> You can confirm the ISS is in APRS mode by checking the age of packets on
> this site:
> www.ariss.net. As of right now, it appears the packets are less than an
> hour old, so clearly the ISS APRS downlink is on and working.
> You can try to send a few packets, but with the rubber-duck you won't make
> it in. With a full sized 19" whip you can make it (but only if you have the
> uplink all to yourself). Of course, the arrow antenna should do it fine.
> But there are two other approaches.
> 1) A simple dipole held horizontal 18" above a ground plane of some kind.
> Chicken wire, rabbit fencing, should be about 4' square or so. This should
> give you about 5 dBi gain. Then you should be able to get in during the
> center 2 minutes of the overhead pass each day.
> 2) Use the same ground plane above, and install a 58" vertical whip antenna
> on it. That antenna will give almost 7 dBi gain when the ISS is above 30
> degrees (center 2 minutes of an overhead pass).
> When you TX and see the radio flash "MY POSITION", then you know you got in
> and everyone else saw you too. Or send an email to yourself using the APRS
> message feature.
> Good luck!
> Bob, WB4aPR
Thanks for the advice. I think I am going to try exactly what you
describe with respect to receiving APRS packets from the ISS. Then if
that goes well I will most likely get a portable Arrow.
I do use for HF a Buddipole - I am pretty sure I could make a vertical
with enough gain to accomplish bullet item #2 above. However, its
less maneuverable for manually tracking a satellite.
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