Mark,
You and I should see almost the same footprint on NO-84.
I will try to be on this afternoon, Monday, for the 19:20Z pass and will bring the UHF signal up for you to hear. The beacon, at 314 Hz, is strongest. My downlink signal has been 10 to 20 dB lower than that.
So we can help you figure out what needs to be done, would you describe your station setup for receiving from your antenna, pre-amp, tracking program, radio, computer, decoder. And then the same for your transmitting radio.
Listen on the 19:20Z pass - maybe a minute later at your location since it is a descending pass.
Jerry, W6IHG
On 12/14/2015 2:30 AM, Mark Lunday wrote:
Jerry, I saw absolutely nothing on the downlink. Static.
Mark Lunday, WD4ELG Greensboro, NC FM06be wd4elg@arrl.net http://wd4elg.blogspot.com
-----Original Message----- From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Jerry Pixton Sent: Sunday, December 13, 2015 8:44 PM To: amsat-bb@amsat.org Subject: Re: [amsat-bb] NO-84...operator error?
Mark, et al
The PSK passband is about 3 KHZ. Your radio USB bandwidth may be the limiting factor.
Are you seeing the beacon at about 314 Hz if someone gets it keyed up?
I discovered today that if I just send idle tones (key up with no message) that the 31.5 baud detector circuit is much quicker to turn on.
I am confused by the question: Mark, what signal are you seeing in the psk waterfall? I assume this is a waterfall of the downlink audio? Then was this your signal?
If your radio uplink VFO is set at 28120000 Hz in USB, and I modulate with a 1500 Hz audio tone (however I generate it) I would expect to hear a 1500 tone on the FM or 1500 Hz on the PSK31 waterfall. This is ignoring any error in my uplink vfo and any translation error in the bird - both of which are real. The other big error is doppler.
But DopplerPSK is doing a reasonable correction of the modulation tone so that when you set a desired center frequency of 1500, you get close to that most of the pass with some noticeable error around TCA but still decodable. But if you are not doppler correcting your uplink signal all bets are off with the plus/minus 700 Hz tone shifts seen.
So I guess a test of how well your doppler correction is working is how close your downlink signal is to the target central tone you have set for the uplink?.
Jerry, W6IHG
On 12/13/2015 7:51 PM, Mark Lunday wrote:
Again I tried to send through AO-84. I was on 28120 with a tone of 1.5 kHz. I saw nothing on the 435.35 downlink. At all. The 1932 UTC was good enough that I should have seen something.
I was also not able to send a packet through on 145.825. How wide is the passband for PSK on the uplink?
Mark Lunday, WD4ELG Greensboro, NC FM06be wd4elg@arrl.net http://wd4elg.blogspot.com
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Dr. Jerry R. Pixton, PIXOS Designs http://www.shentel.net/pixosdesigns/RadioTuner/ jpixton@shentel.net
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