[amsat-bb] Advice on antennas for working the LEO's
jkopala at gmail.com
Wed Feb 21 14:25:32 PST 2007
I just thought I'd throw in my 2 cents. I don't have a great deal of
experience with satellites, but I will offer a few comments based upon my
The antenna by Tonna with 13 DBi on 2 and 16 DBi on 70 is going to have a
fairly narrow beamwidth and is obviously a fairly long antenna. It will
need to be pointed with reasonable accuracy. If you are 30 degrees off you
might as well be pointed the other way. With that much gain, you should be
able to work most satellites without the preamps. The problem is aiming the
antennas. I recommend using azimuth and elevation rotors. Azimuth alone
won't do it with narrow beamwidth antennas if the satellite pass reaches a
significant elevation. The software programs will tell you where to aim the
antenna and you can easily do that with the rotor control boxes while
working stations on the radio. The adjustments are easy and don't take that
much time away from operating.
I tried an experiment with a tripod and a set of KLM antennas mounted on a
cross boom. Aiming a large set of antennas manually can quickly turn into a
full time job. I was testing this to see if it was practical to take to
After trying the tripod setup, I modified the setup and put in my rotors.
Using the rotor controllers, made this very workable. I'll send you a
picture separately of the setup. Basically, I had a stake in the ground, a
5 ft mast slipped over the stake with a rotor at the top end. The rotor is
guyed with 3 additional stakes. Above the rotor is another 5 ft mast
section, elevation rotor, crossboom, and VHF and UHF satellite antennas.
Obviously, if you are using a single dual band antenna, the whole setup is
somewhat simpler. What you see in the picture is destined for my roof plus
If you use an antenna that is small enough to hold and point by hand, you
will lose a lot of gain vs the big antenna, but it will be a lot easier to
point. You still need real time data for the azimuth and elevation and some
sort of azimuth and elevation aids would help. Some people enjoy working
satellites with the Arrow antenna. Personally, I have not have a lot of
luck with reading azimuth and elevation, manually aiming, talking on the
radio all at the same time.
Date: Wed, 21 Feb 2007 09:44:00 +0000
From: Gary McKelvie <garym at garym.org.uk>
Subject: [amsat-bb] Advice on antennas for working the LEO's
To: amsat-bb at amsat.org
Message-ID: <184.108.40.206.2.20070221092821.023911f8 at mail.btinternet.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed
Hi to the List,
My names Gary, I'm just getting started in the sats, initially
looking to work the LEO's with FO 29 in particular.
The station is going to consist of a Yaesu FT 847 cat controlled by
Ham Radio Delux to control the radio for Doppler.
It's suitable antennas that I have a problem with from web pages etc
a lot of people seem to use the arrow antenna,
which unfortunately as far as I can see is not available here in the UK.
There is an antenna by Tonna which is a 9 element on 2 and 19 element
on 70 claimed gain is 13 dBi on 2 16 dBi on 70.
The feed line I will be using to get to the antenna will be a short
run of West Flex 103 (which is half the loss of RG 213)
I'm hoping to avoid the use of pre amps if possible as getting power
to them is a problem.
This antenna set up will be temporary in nature, with it being set up
each time it is in use.
I will be able to rotate the antenna in azimuth by hand or using a
So would this setup work?
So really all I'm not sure is how effective this setup will be and am
looking for ideas and suggestions.
Web : www.garym.org.uk
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