PSAT

PSAT PSK31 experimental software

  
  (Image Credit) JE1CVL


[amsat-bb] PSAT PSK31 experimental software
aflowers at frontiernet.net
Wed Jul 15 22:41:25 UTC 2015

I put together an experimental program called DopplerPSK to compensate
for the Doppler shift on the NO-84 (or NO-83) PSK31 uplink. In essence,
its a PSK31 transmitter that is merged with an orbital propagator to
cause your transmitted signal to drift exactly opposite to uplink
Doppler effect. It does this in a phase-continuous correction so that
you don't get errors due to discontinuous frequency adjustments from
controlling a radio in discrete steps.

In the case of PSAT and BricSat, it should cause your signal to stay
at constant frequency in the satellite's uplink receiver, and thus you
should get a stable frequency on the FM downlink as well.  In turn,
this means you should be able to use your favorite PSK31 demodulating
software to copy the downlink since the frequency drift should stay well
within the AFC tolerance of the software.

Anyway, if there are any adventurous people who are set up to give this
a go, I would be interested in seeing if it actually works. You can find
a rough quick-start guide (which contains an explanation of how it works
and what you need to get started) and the application package on the
rather minimalist page here:

http://www.frontiernet.net/~aflowers/dopplerpsk/dopplerpsk.html

It's an experiment, so be prepared for disappointment.  I am :-)
Andy K0SM/2


Re: [amsat-bb] PSAT PSK31 experimental software
Robert Bruninga at usna.edu
Thu Jul 16 02:50:04 UTC 2015

Great! This PSK31 TX-only software for PSAT PSK-31 solves three problems!
1) as a separate TX-only program, it lets everyone run FULL DUPLEX with
   their existing PSK31 for receive
2) It makes your signal constant in the waterfall for You
3) and for everyone else even if they are not running anything special!

Maybe Andrew can comment on whether two separate sound cards are needed
or if it is possible to use a single sound card?

Bob, WB4aPR


[amsat-bb] Full DUX PSK31 Operating ideas:
Robert Bruninga at usna.edu
Thu Jul 16 13:29:32 UTC 2015

Can I assume the TX uplink software has the usual BRAG text and CQ
features, since the expectation is that users will continuously transmit
throughtout the entire pass and the operator has plenty to do other than
type continuously at the keyboard.  So I envision some continuously
running brag text including CQ's the call, the HF antenna, the power, the
grid, the location in DDN/DDDW whole degrees maybe (for APRS purposes),
the downlink antenna, and so forth.  And then maybe the looping uplink
will stop at the next item separator and allow the operator to inject
keyboard text.

In other words, the loop just runs.  But if the operator begins typing
(maybe he sees a buddy in the dowonlink) he just starts typing and the
LOOP stops at the next break in loop elements and inserts the typed text.
Im thinking that elements in the brag string would be separated by " - "
but then when ever the operator types text, then it is inserted in the
stream beginning with [ then text goes here and ends with a ] when he
hits the enter key?

By having a common system of continuous brag items and interjected live
text, then we all have consistent expectations as to what the PC is doing
versus the operator?

Bob, WB4aPR


[amsat-bb] PSAT PSK31 experimental software (BRICsat too)
Robert Bruninga at usna.edu
Fri Jul 17 00:31:38 UTC 2015

Remember to TEST your 10m PSK31 uplink about 10 minutes early and you may
bring up BRICSAT PSK31.  I may have just heard it about 6 minutes before
PSAT.  Same uplink and same downlink as PSAT.

Bob, WB4aPR


Test by DK3WN on 16 July 2015
Up: DopplerPSK
Down: DigiPan
It works great! DK3WN am the station at 1000Hz.

  
  (Image Credit) DK3WN