[amsat-bb] Re: Antenna advice

Anthony Monteiro aa2tx at comcast.net
Fri Jan 4 17:30:59 PST 2008


At 06:01 PM 1/4/2008, Jeff Mock wrote:
>I'm new to satellite stuff.  I got an Arrow-II antenna to get started.
>It works pretty well.  I live in San Francisco and I can go on the deck
>or hang out the window and hear the easy satellites.
>
>I would like to graduate to sitting in a chair, inside, with two free
>hands, while working a satellite.  What is a good choice for the next
>step up for an antenna that I can install on a flat roof for mode-J
>operation?
>
>Do I need an az-el rotator for the next step up or is there some
>cheaper/simpler solution?  It will be about a 75-foot cable run from a
>roof antenna to my radio, will I need a mast-head type preamp for the
>receiver?
>
>thanks,
>jeff

Hi Jeff,

You can work all of the SSB and FM LEO satellites with just omni-directional
antennas. I personally managed to get VUCC-satellite (#58,) 49 
states, and about
40 countries on LEO satellites using just omni antennas.

I think I may have one of the longest distance qsos on a LEO sat at
7084 Km using only omni antennas (but Bruce VE9QRP and his
"International Panel of Judges" may have a comment on that! :)

For mode B (VO-52 and AO-07) you do not need a preamp as long as you use
low loss coax. Shoot for 1 dB total loss to the antennas. I use
LMR-400 and LMR-600 depending on the length and band.

For mode J, a preamp at the antenna is essential for all cases,
even with a beam.

In any case, I can highly recommend the "EZ-Lindenblad" for
a 2m antenna in the August 2007 QST:

http://www.arrl.org/qst/2007/08/monteiro.pdf

So, to more directly answer your question, you can certainly
make lots of satellite qsos without needing an AzEl rotor
system It is more difficult using omni's but once you get the
hang of it it is not that difficult.

welcome to satellites and 73,
Tony AA2TX



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