Hi Gary,

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 limited experience.

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 scout outings.

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 additional antennas.

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.

John Kopala N7JK

Date: Wed, 21 Feb 2007 09:44:00 +0000 From: Gary McKelvie garym@garym.org.uk Subject: [amsat-bb] Advice on antennas for working the LEO's To: amsat-bb@amsat.org Message-ID: 6.2.3.4.2.20070221092821.023911f8@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 azimuth rotator. 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.

Regards

Gary G7USC

Gary McKelvie G7USC Web : www.garym.org.uk