leosatelliteoperations-currentsetup

LEO satellite operations

My preferred radio for satellite work is the Kenwood TH-D7AG, for the simple reason that is has full duplex capability. Not that satellite work is impossible in simplex, but duplex is so much better as you hear what is going on at all times, so you create less undesirable interference than in simplex. You also hear your own transmission coming back from the bird and you know you made it in there. Of course you don't know if and who heard you as that depends on their skills and equipment too, but then you did your part and that's all you can do.

I have at first operated with the Yaesu VX-7 and the Yaesy VX-2. Both radios can be used for satellite work but only in simplex mode. I had many contacts with these two radios but the full duplex feature of the Kendoow TH-D7AG made things so much better I never looked back.

In order to keep abreast of the satellites' movements, you need a satellite tracking computer program. My favorites is Scott Hather's Satscape http://www.satscape.co.uk A good solid program, no bugs, no nags and free. Orbitron is ok too, but I seldom use it as I'm much more familiar with Satscape. I also use an old PocketPC that runs PocketSat+ for the same rpurpose as Satscape, but this allows me not to be depending on a full laptop and have the same data right underhand when operating. I found it more practical than pre-printed data sheets as if an error has been made in the time zone, with the sheets all you know is that you are listening to the sounds of silence and now have to find out what was the mistake. With the PocketPC I just have to recalculate.

Antennas:
You cannot operate satellites efficiently with a rubber duckie. You need something better. Here is a picture that shows you how easy it all is:

All it really takes is the muscles to hold the Arrow antenna for 10-12 minutes or so and the dexterity to work the radio with one hand. I use a voice recorder to keep track of my QSOs when operating like that, as otherwise how could I take notes? The operator is yours truly, at a SAR conference in PA.

I made a lot of contacts holding the antenna like that. It helps is you have a strong wrist and forearm. Now if you want to lighten the load, you can also use the Pryme AL-800 antenna. It is much smaller and lighter, but also does not have as much gain, reception is not as good and you need to practice the technique that will allow you to keep receiving the satellite. Another learning curve, as most of the time, the antenna is either pointed away from the satellite or even right to the ground, or using the hood of a vehicle as a reflector etc.

Now this is not how I operate nowadays. I've gotten a little more sophisticated and have a system that works better, with the same components and some additions.

From the top down, you can see the Arrow II antenna (more details in the next pictures) with its Hamtronics 440 pre-amp and the rather large switch for the 12v battery powering the pre-amp. Below that is the little tablet, notice the cut on top as it allows it to stay on the tripod's upright. The clipboard is attached with some self adhesive Velcro to the tablet.. The Kenwood TH-D7AG is temporarily secured to the upright. I hold it in my left hand while operating. Notice the ear-piece/mic on the right hand side. You cannot use the internal speaker as it creates feedback when talking. I also have a cheap but waterproof watch attached to the tablet. It makes things easier to log the time of the QSO, when wearing long sleeves, especially in winter. Let's see a few more details of this setup.

More general picture of the satellite antenna setup

. Here you can see the SLA 12 volt battery feeding the Hamtronic 440 pre-amp.

The Hamtronics 440 preamp

This is the Hamtronics 440 pre-amp that I attached to the mast with Velcro cable ties.

This is how the antenna meets the tripod, a simple piece of PVC and a large hose clamp. The antenna was taken apart in its middle, then inserted and put together. Some plastic foam is giving it enough friction to allow for horizontal or vertical polarization and remain in that position.

The entire system is still portable as I need to get out of my driveway and 100 yards up the road for best reception. The antenna can be taken down from the tripod with minimal disassembly. Power to the pre-amp is easy to disconnect at the PowerPole connection.

There is much more to satellite communications and others have done a great job explaining it. This is just the setup that currently works best for me and someone might be able to steal some of my ideas and come up with a better one. Hopefully that better one will be shared.

One last trick. It is so easy to forget the time of each pass. On days that I want to devote my time to satellites, I just use the appointment feature on my cell phone for each pass I want to work. At home, all I need is the relative maximum height of the pass as I know more or less which way each will go. And this is also true even within a reasonable driving distance. But you need to orient yourself and know the maidenhead grid square. My Garmin 60CSx GPS does all that for me.