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Satellite Mobile [was: "9600 Baud Pacsats/Portable?"]



    9600 baud pacsats from a Mobile.  I was using only an OMNI whip over a
    ground plane. I would be interested in your experienced reply to these
    questions:
	...

    I could clearly hear the signal of KO23 on 435.175 but no packets.
    I could not detect anything from UO-22 on 435.12 nor KO-25 on 436.5.

This may seem counter-intuitive, but try a 2 meter quarterwave tuned for
decent SWR for in the 70cm satellite sub-band.  That shouldn't be hard, 
since 146*3 = 438.  Now, as many folks now, a 2m J-pole or quarterwave 
doesn't work very well at 70cm for repeater or other terrestrial use.  
That's because there's a slight loss at the third harmonic due to the
pattern vertically, e.g. most of the energy is skywards.  But that's 
just what you want for 70cm LEO work!  There's an annoying overhead
null for AO-27, but otherwise, it worked well for me. I operated AO-27
mobile for a year using an FT-5100 without a preamp, and worked approx.
25 states/provinces (which included about 5 contacts with a gain omni 
on low elevation passes).  And as a added bonus, no diplexer was needed
with the homebrew 2M quarterwave.  But you need to have a decent ear
for AO-27 and/or be away from urban RF clutter.  The PACSATs should be
easier, as i understand that the downlink is much stronger.

    Has anyone operated portable with 5 watts from briefcase antennas?
    It should be easy to put together a 3 element uplink and UHF downlink
    collapsable antenna.

I now operate QRP portable on AO-27, as do a number of experienced
satellite operators.  Most of them use the excellent Arrow 146/436
hand-held cross-polarized yagi, generally with a built-in diplexer.
Lately, N2YQP and KI0AG have been running 1/2W!  I run a different
homebrew dual-band gain antenna (no diplexer needed) that fits easily
in a 4' mailing tube.  If AO-27 weren't so swamped already on weekends,
i'd write it up.  *Sigh*  Skeds welcomed to all 50 states and most 
provinces.

		    73s and good luck!

			-- KD6PAG ("Networking Old-Timer, RF newbie")


P.S.  If you've been waiting, note that a large stack of QSL cards will 
go out when i get a new permanent address for the SASE.  If you have a 
card for me, please mail it in the next few days or wait until my on-line 
callbook address changes from Palm Avenue, as mail forwarding where i am
probably won't be reliable, judging from how much mail i get for previous
residents.  And if i don't need a card back from you (or if you ask), it
will go out sooner.

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