Fall 2002 Issue

Photo 1. The author’s satellite array. Just 20 feet high, it provides plenty of ground clearance, is easily accessed for maintenance, and is hidden from the public street. (Photo courtesy WA9AFM)

SATELLITES

Antennas for Satellite Work

 By Tom Webb, WA9AFM

Before we begin this month’s topic, I must correct some erroneous information in my summer issue column. I made mention of an HF board for the Yaesu FT-736. This was incorrect! The HF board was an accessory for the FT-726! Regrets to all the 736 owner/ operators who thought they
had discovered a little-known accessory, and especially to Chip Margelli, K7JA, of Yaesu, who fielded all the calls from operators wanting to know where to get hold of “one of those HF boards.”

The Antenna

Now to the business at hand: You have selected a tracking software program and a satellite rig; our next consideration will be antennas.

When I first took up the hobby of amateur radio as a junior high school student, my Elmer imparted several important axioms to me, one of which was “If you have an extra buck to spend, put it into your antenna.” This is certainly true in selecting antennas for amateur radio satellite operations.

Several factors can impact your selection—which birds you will work (LEO, AO-40, digisats), location (i.e., covenants and restrictions pertaining to antennas, or room to spare); unattended operations; your budget . . . the list goes on.

Where Do You Put Them?

One thing that isn’t critical to mounting satellite antennas is height. Yes, it’s best to be clear of trees and buildings, and high enough to be out of the reach of young fingers or folks strolling by, but going to 70 feet will offer no real advantage. Remember, you are communicating through a satellite several hundred or thousand miles away, so an extra 50 feet isn’t going to help.

Ground or roof mounting near the shack is the ideal situation. If you are planning on ground-mounting steerable antennas—i.e., azimuth and elevation control (AZ/EL)—such arrays should have enough height to allow an adult to walk under them without bumping the antenna (or putting out an eye). Some folks have elected to mount their satellite arrays on a tripod with minimal ground clearance. This does offer the advantage of easy access, which can be a real plus when antenna work is needed. In the case of a small, stationary array, give the attic (if you have one) some consideration.
 

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