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Simple OMNI receivers for LEO's.



Dont forget also that a 1/4 wave 2 meter 19" whip 
over a ground plane about a meter in diameter also 
makes an EXCELLENT UHF 3/4 wave omni antenna 
above about 25 deg.  It has about 7 dBi of
gain (and the antenna is perfectly dual band, since
it is 1/4 wave at 2m.).  

THus it works well for ISS and PCSAT, and VO-52 on 
2 meters above about 15 deg and on the other birds 
above 25 deg, the 7 dBi of gain there and the fact that
the birds are 6 dB closer makes ALL amateur satellites
hearable above those angles on nothing but this whip.

But again, the UHF birds are above those angles only about
1/3rd of the time.  But it sure makes for a simple,
no hassle, no moving parts receive system.  Hooked to
a TH-D7 HT running satellte tuning software, tuning the
radio to every satellite that comes into view, you wont
miss a thing (except the low passes)...

See the bottom half of this page:

http://www.ew.usna.edu/~bruninga/astars.html

Also see the percentage of time that a LEO satellite
is in view at various angles on:

http://www.ew.usna.edu/~bruninga/rotator1.html 

And FINALLY, remember that your car with a center
roof mounted whip and only 10' of coax will always
hear satellites better than any other omni with 50
feet of coax in the shack.  AND you can move it
around blockages.  Satellites from the mobile works
well...

de WB4APR, Bob

>>> "John Henderson" <jah@ec.rr.com> 06/17/05 9:32 AM >>>
Thanks Bob, 

The most definitive answer I got. I plan to get a preamp for 70cm just
to give it a try on the listening end. I will most likely build me a
couple of yagis and forget the omni-dir approach. I was trying to keep
it simple ( rotors,etc) but I now know you give up too much taking that
route.

I have pl259's in the 9913. I plan to switch them out to N's. What is
the dbm data of the two? I've looked on several websites but didn't find
the data.

Really appreciate the FB reply.

73,  John 
N4NAB/ FM14lq
AMSAT # 32411
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