Re: [amsat-bb] PSAT PSK31 experimental software

17 Jul 2015

      Thats what I was most interested in the antennas. describe them...
Joe WB9SBD
Sig
The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com
On 7/16/2015 5:43 PM, David W0DHB wrote:
...
Thanks Joe I forgot BB would wrap line.
This one works also
https://www.dropbox.com/s/r6ywkczcf95o3f2/NO84.wav?dl=0
Base equipment is
10m SSB Transmitter with the ability for TX audio being fed by Computer
sound card.
70cm FM RX / antenna system capable of copying satellite downlink and able
to feed RX audio to Computer.
Computer with Windows/Mac , DopplerSQF software and software that will demod
PSK31 (Fldigi,Digipan DM780 to name a few)
Software to do downlink doppler tuning is very useful,  but not required.
Dave W0DHB
-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Joe
Sent: Thursday, July 16, 2015 4:24 PM
To: amsat-bb@amsat.org
Subject: Re: [amsat-bb] PSAT PSK31 experimental software
hEDRE i FIXED THAT url ALSO,
*http://tinyurl.com/q3np2sm
Joe

Sig
The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com
On 7/16/2015 2:57 PM, David W0DHB wrote:
...
Andy
Here is a recording of the 1930 pass of NO-84
https://www.dropbox.com/s/2qtb5d2cm3ktrr0/FM%20435.359944MHz%20%5B12k%
5D%207
-16-2015%2019%2033%2052.wav?dl=0
Bob KO6TZ and I had a successful QSO. My audio was set at 1500 Uplink
frequency  of 28.119700 MHz .
The signals seemed to be stable, decoding at my end (DM780 ) was not
stellar, I'm running the recording through fldigi, MixW and Digipan to
see if it's any better.
Dave W0DHB
-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of David
W0DHB
Sent: Thursday, July 16, 2015 8:41 AM
To: 'aflowers@frontiernet.net'; amsat-bb@amsat.org
Subject: Re: [amsat-bb] PSAT PSK31 experimental software
Hey Andy
The ability to select soundcard would be helpful. In my setup TX audio
is fed by a virtual audio cable set to match the 48K sample rate that
DopplerPSK is using.
Folks using windows should set the recording device side of their
soundcard to a 48K sample rate (it usually defaults to 44.1K).
You are correct that the uplink frequency is high, I apply a -300 Hz
calibration offset.
Thanks for all your work on this.
Dave W0DHB
-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of
aflowers@frontiernet.net
Sent: Thursday, July 16, 2015 6:29 AM
To: amsat-bb@amsat.org
Subject: Re: [amsat-bb] PSAT PSK31 experimental software
Bob, Dave;
That's great.  I'm interested in how well it tracks when the satellite
is at a very high elevation and the Doppler is >3 Hz/s.  I suspect the
error is going to be mostly in the estimates of the orbital elements, but
we'll see.
...
I will try to join you on the pass when I can cobble together an
uplink and a downlink in the same place--probably next week sometime
after I get back from vacation.
I think you should be able to share a sound device on most OS's, but I
have not tried.  I assumed it would work on modern Windows OS's
because of the hardware abstraction.  The program appears to run fine
on OSX, but I have not tried running CocoaModem or some other software
next to it.  Ultimately I could also add a demodulator to the program
itself, but that will take some work....I know several hams have
separate sound cards for radio stuff, so I may need to add a device
selection option in case the system default (or whatever Java picks as the
default) isn't what you want.
...
The audio frequency displayed in DopplerPSK is the audio frequency
being send to the radio, not what you should expect in the passband of
your downlink receiver. The LO on PSAT is apparently a bit below 28120
KHz, so if your radio was tuned to 28120 USB (suppressed carrier
frequency) you would expect to be a bit higher than 2000Hz in the FM
passband:
...
http://www.urel.feec.vutbr.cz/esl/files/Projects/PSAT/P%20sat%20transp
onder%
20WEB%20spec02.htm
In general, if you want to be lower in the passband I would lower your
transmitter RF frequency rather than the audio frequency going to the
transmitter.  The reason being that if you have any non-linearity in
the audio chain you don't end up transmitting a harmonic higher in the
band that might bother someone else.  Of course, you can probably see
if this is an issue or not since the satellite also serves as a crude
signal analyzer :-) I chose 2000 Hz as a center since at maximum
Doppler of around 700 Hz, the
~2700 Hz tone should go through the transmitter's IF filter without
too much attenuation while keeping all the third harmonics and most of
the time the second harmonic above the cutoff of a 3 KHz IF filter.
Every radio is a bit different, however.  You may find that the 1500Hz
sweep in the program shows you all your passband ripple in your IF
filter :-)
Since it works, I'm more motivated to improve the ergonomics of the
interface.  Much of that depends on the unique operating practices of
satellite operation.
Andy K0SM/2
On Thursday, July 16, 2015 12:31 AM, KO6TZ Bob
my.callsign@verizon.net
wrote:
The software worked great !!!  Produced a straight line on the
waterfall for the down link.
As expected, I was alone on the pass, so no opportunity for a contact.
I was using digi-pan for the RX, my signal was at around 2200Hz..
Probably an indication the oscillator in my radio is off a bit.  I
think I will lower the frequency from 2000 to about 1600.  That will
put my signal lower in the VF pass band.
I like the program.  Had good copy.
THANKS.....
BOB  KO6TZ
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Opinions expressed are solely those of the author, and do not reflect the
official views of AMSAT-NA.
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interested persons worldwide without requiring membership. Opinions
expressed are solely those of the author, and do not reflect the official
views of AMSAT-NA.
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Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb

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Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb