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More Mobile 9600 Baud Station



Thanks to all who made antenna suggestions in response to my message on the
same subject posted on 2 November. There were many thoughtful and
interesting ideas, but no "Silver Bullet".  I fear I am treading where
others have not been.

It appears  the descriptors "mobile" and "9600 baud" are mutually exclusive
when it comes to working UO-22, KO-23, and KO-25.  The Pacsat protocol used
by these birds expects you to have letter perfect replicas of the directory
and any downloads. If you miss a bit here and there during a pass, it is
normally not much of a problem. The next time around you simply request
fills for the holes and all is well. With a good antenna (I have a 70 cm
eleven element yagi with gasfet preamp) it all seems to work well. However,
if the antenna is marginal and you miss lots of bits you end up using all
the subsequent passes requesting fills. Meanwhile you have downloaded
additional titles to the directory that are also incomplete. Things get
progressively worse until you manually intervene to cancel the requests.

Now, any Ham who has operated mobile has learned  there is always something
out there that  will make disasterous contact  with his antenna. In the
case of motorhomes it is usually a tree limb or a power line crossing the
roadway.  The stinger on my 2 meter 5/8 wave antenna is shaped like a
question mark.  Last summer it was a gas station canopy that got my
screwdriver. $$$$$$    To have survivability we need low profile,
flexible,omnidirectional antennas that handle the wind and striking foreign
objects. These antennas just simply do not have the gain to work the
Pacsats. We get close with quadrafilars and eggbeaters but my mind pictures
one of those dangling from a limb with a large piece of my motorhome roof
still attached.

I have not given up. I think an electrically rotated phased array
constructed with 17-7 stainless whips could do the job and survive. See the
Sep/Oct Amsat Journal or ARRL Antenna Books "Four Square Array".  The
project is on the agenda for next summer.

The best suggestion came from Paul  Williamson who noted I would be in the
Arizona desert for five months with no Internet access. He pointed out that
there is a "cyber cafe" at the Hotel Congress in Tucson where I can get an
occasional "Internet fix".  If I remember correctly, while attending the
'96 Space Symposium in Tucson, another Ham and I found a gourmet Mexican
Restaurant at the Congress. Now, who could ask for a better combination
than that?

Bob Hart, WA7HRA
Hoodsport, WA




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