Cook County ARES Net--Training Segment--2013/08/28

Antenna Maintenance and Spares for EmComm

The summer has gone by quickly. This weekend is already Labor Day, and by the time of the next Cook County ARES Net, it will be Autumn.

There's a long-honored proverb in ham radio that goes something like, "The effectiveness of an antenna is proportional to how cold and miserable the weather was when you put it up." Be that as it may, it's a good time to think about your EmComm antennas before it's too late in the year to do anything about them.

Whether made of wire or tubing, our permanently-installed antennas require periodic inspection and maintenance. The coming couple of months, before the snow flies, can be ideal for that work. Some mechanical parts are subject to deterioration due to weather and sun. Check plastic and rubber items, including the end caps on traps, guys, rope supports, and similar items. Some bearings and pulleys may need lubrication.

Check feedline for damage to the jacket, particularly at points where it may wear against a tower, house, or other support. Inspect your lightning protection. Some elements are consumable or deteriorate. Also, check waterproofing at connectors.

For wire antennas installed in trees, a little pruning or mechanical adjustments may be needed due to growth of the tree, damage, or other natural processes.

And while we're thinking about antennas, it would also be a good idea to take a look at your antennas for your portable and mobile radios.

I recently was volunteering at a public service event and found that one of my longer whip antennas that I use for my portable radio had broken. I had a spare antenna (and a spare radio), so I was still able to complete my volunteer assignment. I have owned that particular antenna for at least five years and it has been subject to some not-so-gentle handling, so it owed me nothing in terms of service life. But our portable radios do take some abuse. Carefully inspecting your antennas may help you spot problems before the affect your ability to work. Even had I inspected the antenna on the morning of the event, I'm not sure there was any visible manifestation of a problem to see. So it is really helpful to have a spare antenna or two.

For EmComm, it's nice to have a spare antenna other than a rubber duck, to which you can connect base, mobile, or portable radios.

There are a variety of J-Pole antenna designs, some using water pipe, some using twin lead, that are relatively inexpensive, easy to build, and may be useful in an emergency. Most J-Pole designs have the advantage that no ground plane is needed.

If you don't want to build your own, Arrow Antennas has a nice commercially-produced design which can be stored dis-assembled. When needed, the antenna can be assembled in a couple of minutes.

Also, if you don't already have one, you might consider obtaining a small dual-band mag-mount mobile antenna. They are small (about 19 inches long), lightweight (a few ounces), can fit in your go-bag, and can offer a lot more range than a rubber duck if you find yourself needing to operate from a vehicle or building with no installed antenna.