[amsat-bb] NO-84...operator error?
mlunday at nc.rr.com
Mon Dec 14 02:30:33 UTC 2015
Jerry, I saw absolutely nothing on the downlink. Static.
Mark Lunday, WD4ELG
Greensboro, NC FM06be
wd4elg at arrl.net
From: AMSAT-BB [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Jerry Pixton
Sent: Sunday, December 13, 2015 8:44 PM
To: amsat-bb at 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
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
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
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 at arrl.net
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Dr. Jerry R. Pixton, PIXOS Designs
jpixton at shentel.net
Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available to all
interested persons worldwide without requiring membership. Opinions
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views of AMSAT-NA.
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