Hi All,
Yes the antennas are dipoles and the spacecraft is slowly rotating around the Z axis on which they are mounted. Therefore you can be in a null when one end of the dipole is end on or nearly end on to your QTH, generally circular polarisation at your station will not solve this but they will make some improvement to the received signal strength at other times!
The speed of rotation is changing by the day. The current status can be seen here: http://forum.funcube.org.uk/viewtopic.php?f=2&t=179&p=822#p822
Many thanks for your on going support of FUNcube-1.
73
Graham G3VZV
-----Original Message----- From: Eric Knaps , ON4HF Sent: Monday, May 05, 2014 9:54 PM Cc: AMSAT-BB@amsat.org Subject: [amsat-bb] Re: AO-73 booming signal
Hello Chris.
I listen daily to AO-73 to gather the telemetry data. I use a 12 elements cross yagi and can switch between left CP or right CP. At low elevations (between 0 and 10 degrees) I also suffer from deep fadings where the signal is in the noise and then slowly coming back.
73, Eric.
Amateur radio station ON4HF Satellite manager UBA Member Amsat-UK Member Amsat-ON
Eric Knaps Waterstraat 30 B-3980 Tessenderlo Belgium
Chris Thompson schreef op 5/05/2014 21:25:
I've also heard a very strong downlink of my signal on a couple of occasions, but not had any replies. I am on the East Coast of the US in Brooklyn.
That said, I get very deep fades with AO-73. I think the antennae are in the x-y plane and are dipoles. They are therefore rotating as the satellite rotates about Z. If you are using an arrow antenna, or similar, then you get a deep null periodically and you can completely loose your signal if you are not careful. Does a CP antenna help with this? Can anyone using CP confirm?
I understand AO-73 rotates about once a minute, or once every two minutes. So you should have a null every 30 seconds or so but it _seems_ worse than that and it's enough to throw you off, especially if you have struggled to find your signal in the narrow downlink in the first place.
Then of course it goes into sunlight and your signal pops out of existence....
All in all, a tricky sat to work. I'm looking forward to my first contact through it.
73 Chris ac2cz
On Mon, May 5, 2014 at 2:18 PM, Paul Stoetzer n8hm@arrl.net wrote:
Agree. It isn't quite as loud or as easy to get a signal into as VO-52, but it's very close.
I had a 70+ degree pass yesterday and my return signal was S8 with 500 mW to an Elk antenna. Unfortunately, all I heard were people trying to find their signals until the end of the pass.
Looking forward to the FUNcube-2 payload on UKube-1 and the FUNcube-3 payload on QB50p2, apparently both launching June 19th, but I see conflicting information about the DNEPR launch for QB50p1 and QB50p2 (with a FM transponder from AMSAT-F). Can anyone confirm that date?
73,
Paul, N8HM
On Mon, May 5, 2014 at 12:52 PM, D. Craig Fox DFox@rwglaw.com wrote:
I was on AO73 last night from southern Cal (DM13) at around 0555z,
calling many CQs. I kept my downlink at about 145.955. My sigs peaked at S9 (no preamp), 5 el fixed at 30 deg.
AO73 was very loud. I had no replies and heard no one but myself. It
does take a little more work to keep up with the Doppler, but this is a great sat and I encourage you to take advantage when the transponder is turned on.
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