[amsat-bb] Re: Antenna advice

[Roger Kolakowski]

Hi Ken...

Of course there are advantages to az/el tracking. With "spot on" TRACKING
you will have better signal levels to work with on receive and be able to
use less power on transmit.

The disadvantages of az/el are that you do need ACCURATE TRACKING or you can
possibly worsen your received signal strength from the Sats. ISS is
especially a challenge as it is so close to the Earth's surface (~200) miles
that it's passes can move across your visible sky really quickly.

Your initial inquiry included a "hands off" requirement. That means tracking
software that controls the rotors automatically. While you are at it you
might as well adjust for doppler. Not much on 2 meters but enough, and a
requirement on 435.

So...your decision becomes...do you stop operating as you collect this
gear,software and fund this transition, or do you take the next step up and
set up an AZ rotor while you are contemplating the rest. How much time do
you have to accomplish this setup? How much money? What type of antennas are
you considering? Circular polarization? Antenna gain vs required accuracy?

You have mentioned ISS several times...it can be worked with a HT and a
rubber duck...at least on a clear pass. It has been shown many times that
one of the best antennas for ISS is a 19" whip over a good groundplane. The
same antenna works on 435 also.

Your available time and money should help set your goals for your antenna
system and reap the rewards you are satisfied with.

Me...I'm a minimalist  ;-)

Roger
WA1KAT



----- Original Message ----- 
From: "Ken Owen" <n6kth at n6kth.com>
To: <amsat-bb at amsat.org>
Sent: Saturday, January 05, 2008 11:20 AM
Subject: [amsat-bb] Re: Antenna advice


>
> Hi folks:
>
> So, I understand those that say it's not worth "chasing the last 2
percent"
> with an elevation rotor.  Is there ANY advantage to having EL capability
for
> satellite purposes?  What about for working the ISS?
>
> Thanks,
>
> Ken, N6KTH
>
>
>
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