[amsat-bb] 38k4 packet operations on AO-51 Nov 14-18, 2010

Mark L. Hammond marklhammond at gmail.com
Fri Nov 12 06:29:51 PST 2010

Hello All,

Just a reminder that we'll be running a few days of 38k4 packet
beginning Sunday afternoon/evening until Thursday afternoon/evening,
as per the schedule below.  Note the voice repeater will be OFF.

Please keep in mind that receiving packet at 38k4 requires more than
your "stock" FM receiver and TNC.  Generally speaking, folks are using
a Symek board installed in their satellite radio to tap the IF which
is then fed to a high speed TNC.  Other options for a receiver include
a PCR-1000/1500/2500 in FM mode with filters set to 50 kHz (NOT
Wide-FM)  (I think that's the right filter width).

Please remember Douglas Quagliana's KA2UPW soundcard decoder (as
presented in the AMSAT Journal a few issues back) that can be
downloaded here:  http://www.quagliana.com/     Look for Willow and
Sabins.    I suggest you get the software and test it out at 9600
before you attempt 38,400, so to become familiar with how it works
with your receiver.   It does work at 38k4--but remember you must have
an appropriate receiver!

It is possible to use some of the SDR stuff I'm sure, if you record
with your SDR software and play back through KA2UPW's Willow program.

I have a few options in my shack, as I've been running 38k4 since the
good old UoSat days:

Receivers capable of 38k4 (up to 76k, actually):
TS-2000x with Symek IF board
TS-790A with Symek IF board
Icom PCR-1500

For decoding:
Paccomm Spirit/Sprint-2 Satellite TNC models with 38k4 filters installed

My preferred combination is the TS-2000x with Symek IF board feeding a
Pacomm Sprint-2 satellite model.  I seem to get the best performance
out of this combo.

Here's a reminder of the schedule:

November 14 (late UTC)
38k4 Baud PBBS Operations, L/U
Uplink: 1268.705 MHz FM at 9600 baud
Downlink: 435.150 MHz FM at 38,400 baud

November 18 (late UTC)
FM Repeater, L/SU
Uplink: 1268.705 MHz FM (no PL tone)
Downlinks: 2401.200 MHz FM *and* 435.300 MHz FM (at low power!)

Mark L. Hammond [N8MH]

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