Re: [amsat-bb] Re: [psk31] PSK31 Satellite Uplink on 10m (final plan?)

[Bob Bruninga <bruninga@xxxxxxxx>]

> So 2/3rds of the time the Doppler rate of change is in the range of about
> 3 Hz per second or less.  It looks like  90% of the time it is 5 Hz or
> less.  And worst case is 9 Hz change per second.

AND one other thing, now that the total doppler can accumulate over 1200
Hz for the whole pass, it will be better if software written for this
application adjusts for this Doppler on the Uplink so that the relative
position of everyone in the passband will remain constant.  This should be
easy to do, however, because the Satellite is full duplex, so the user's
sound card can be monitoring his own signal on the downlink and making AFC
changes on the uplink to keep him at the same frequency on the downlink.

Of cousrse, the PSK-31 software will need to be full duplex as well so it
can listen while it is transmitting and the user will have to click on his
own signal to tell the software WHICH signal to be tracking for his own
AFC.  But notice that you can be RECEIVING from EVERYONE while you
are TYPING your transmission, so the short 8 to 10 minuute pass will be
an exciting burst of HAM radio!  Drink your coffee before the pass, you
wont have time during it..

In that sense, it may be ONE-PERSON-PER-CHANNEL key down during the entire
pass.  And they converse with everyone...  Hummh...

I remember we went through this conclusion of UPLINK AFC almost 2 years
ago when we first started talking about this mode, but since this project
has come out of the woodwork just recently, I am just starting to remember
where we had gotten to before...

de WB4APR, Bob


----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org