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PSK Birds



One of the greatest ways to get the largest number of people on the birds
with live QSO's would be to use the DIGIPEATERS on AO-16, LO-19 and IO26.
These birds have had DIGI enabled for the last few years, but noone uses
them because they required special PSK modems.

But this is NO LONGER TRUE.  Anyone with a PC and SOUNDCARD has all they
need.

Last year, Doug, KA2UPW wrote a sound-card Manchester UPLINK for these
birds, but no one has yet written an AX.25 1200 baud PSK downlink DSP
program.  Yet there are many talented authors who could...

With this software, ANYONE with a PC and soundcard could work these 3
satellites anytime, anywhere...  There are many things that suggest its
time for a new look at this:

1) DSP software for sound cards abounds and is EASY to use. (look at the
fantastic popularity of PSK-31)..

2) Finding laptops/PC's with sound cards is now ROUTINE.  Everyone has
access to one.

3) With the loss of KO23, KO25, SO-35 in the last few months and the
delays in AO-40, we are seeing our on-orbit satellite assets deminishing.
Yet, we have 3 perfectly good (?) REAL-TIME DIGITAL RELAY satellites on
orbit not used by anyone...

4) PSK downlinks are very good weak signal modulations.  With DSP
software, ANYONE can recevie them...

CONCLUSION:  All we need is a little software on the ground and anyone
with an FM rig can transmit to these old 1200 baud DIGIPEATING birds, and
anyone with a downconverter and HF rig can RECEIVE them. 

Dont want to carry an HF rig?  Build the $45 HF WARBLER in this months QST
and a 435 MHz to 3.58 MHz downconverter and there you have an SSB receiver
to plug into your laptop...  Between passes, unplug the downconverter and
work the other WARBLERS on 3.58...

We are just beginning to see the power of DSP in enabling really simple
hardware lashups become very powerful comunications tools...  To quote a
famous ad:

"you don't need no stinkin $1000 satelite rig"...  

and its fun to build your own $45 SSB rig in an evening.  Of course, now
you need a $1000 laptop... and a downconverter....  Aw shucks, build
donwconverters for every band and use the $45 WARBLER 3.58 MHz SSB
transceiver as your IF for everything... <grin>

Yes, AO-16, and LO-19 and IO-26 may not be runnning DIGI-ON today, but
that is only because no one is using it and so the incentive of the ground
controllers to keep the birds fully up in that mode is not there.  They
kept them up in DIGI mode for at least 3 years and still no one used them
for PACSATs or DIGIPEATING...

Its time to take a fresh look at this... EVERY ONE WITH A PC now HAS the
necessary HARDWARE MODEMS/TNC to use these birds.  Lets use them...

bob


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