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Topband: psk/digital experiment

To: <topband@contesting.com>
Subject: Topband: psk/digital experiment
From: "Jim Jarvis" <jimjarvis@comcast.net>
Reply-to: jimjarvis@ieee.org
Date: Thu, 22 Apr 2004 12:05:15 -0000
List-post: <mailto:topband@contesting.com>
Folks,

I seem to have triggered both interest and anxiety, and
caused some speculation with my proposal.

So, I have three messages to deliver:

1)  1805 +/- is the presumptive QRG, pending review of int'l allocations.
If I find good reason to contravene the arrl bandplan, I'll get back to you.
Such circumstances would likely suggest need to modify the bandplan.

2)  You can't explore high-loss paths with low link-budgets, I don't care
what modulation you use.  I'll apply the maximum clean power I can run,
in the largest antenna I can muster, with separate RX antennas, and RX
bandwidths down to 30 Hz.  The purpose of the experiment is to see what
can be done.  Once communications has been established, I intend to reduce
power to determine the minimum workable, and compare it against the
calculated link budget.

3) psk31 is susceptable to phase shifts from polar flutter.  It may not
be robust enough for those paths.  MFSK16 has been proposed as a more
workable alternative.  It's also wider bandwidth.
   My initial assumption was that psk31, being narrower than most cw
signals, would slide into a weak signal area with no difficulty.  That
is NOT the case with MFSK16.  Work with the latter will be restricted to
the 1800-1810 digital mode bandplan.

Nothing will happen until I get the TX antenna up, which is planned for
Fall.  After all, it's sailing season, and I'm on the Chesepeake.
I'll publish start-of-test and planned schedules here, and announce myself
on
packet, when active.  So you can relax until then.  Have a great Summer!

N2EA
jimjarvis@ieee.org

ps:  I'm a cw contester...no experiments on contest weekends.


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