Re: [amsat-bb] Falconsat-3 and APRS HT's?
Greg,
You are going to have a very hard time copying Falconsat with omni/whip antenna's. Yes, it's a strong downlink, but "strong" for amateur satellites is misleading... It's nowhere near as strong as the ISS voice radio, for example, which is easily picked up on my scanner duckie.
It's supposed to be over one watt, but I can pick up AO-85 with a stronger signal, if that gives you any idea. Also, Falconsat has some really serious polarity fade, so there's another issue. I can go from roughly S7 to 'nuttin by rotating my arrow 10°.
--Roy K3RLD
Ok, so I must be doing something wrong. I have an RTL-SDR dongle hooked to a deep-fringe TV antenna in the attic which is my all-purpose scanner setup. I can barely make out the 9600 baud downlink from FalconSat-3 in the GQRX Waterfall, seeing a good bit of fading during the pass. At best it's a faint bar; mostly not there at all. My D74 hand-held, with a Diamond RH-77B whip antenna decodes nothing, assuming there was something to decode. Tried this on 3 passes this afternoon. Nada. APRS traffic on 145.39, by comparison, shows up really well. I thought I read that the satellite had a nice strong downlink. 435.103, plus or minus. I've not done much of anything with 9600 baud packet, so don't have much experience to draw from. What's wrong? Equipment, operating, or expectations? Greg KO6TH
On 10/03/17 07:07, Roy Dean wrote:
Greg,
You are going to have a very hard time copying Falconsat with omni/whip antenna's. Yes, it's a strong downlink, but "strong" for amateur satellites is misleading... It's nowhere near as strong as the ISS voice radio, for example, which is easily picked up on my scanner duckie.
It's supposed to be over one watt, but I can pick up AO-85 with a stronger signal, if that gives you any idea. Also, Falconsat has some really serious polarity fade, so there's another issue. I can go from roughly S7 to 'nuttin by rotating my arrow 10°.
While polarization is still an issue, you might try a square-corner reflector as a starter antenna:
http://www.qsl.net/ve3rgw/corner.html
Of course, you'll want to upgrade it with a rotator to track the satellite, but aiming it by hand should work fine. Keep the coax loss low, or, for both NF improvement and to make up for coax loss, add a LNA right at the antenna.
If you want some historical background on this type of antenna, take a look at this oldie:
http://www.arrl.org/files/file/History/History%20of%20QST%20Volume%201%20-%2...
--- Zach N0ZGO
participants (2)
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Roy Dean
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Zach Metzinger