Saturday, March 16, 2019

Super-quick portable antennas

This weekend in Australia is the annual John Moyle Field Day. Amateurs around the country will be going portable to try to work each other. Antennas will important to their success.

Convenience as well as performance is a consideration. When you're tired at the end of a field day there's nothing worse than having to spend hours dismantling your station. Especially if you're forced off the air early due to an approaching thunderstorm.

Wouldn't it be good if your antenna was so engineered that it can be put up and taken down in a few minutes? That's very possible, particularly for the portable QRP operator. Here's some tips.

* Wire antennas only - no towers or heavy beams.
* Just use one antenna for HF. Preferably multiband. A good antenna coupler to allow this is worth its weight in gold.
* Inverted-vee dipoles or end-fed wires are convenient as they only require one high support. Link dipoles provide low-loss operation provided you aren't changing bands too often and your centre support allows easy lowering.
* Make your antenna as light weight as possible. That may mean avoiding antennas with heavy traps, or thick coaxial feedline. Then you can just use thin tree branches or telescoping fishing poles as supports. As shown in the videos below these can be very fast to erect.
* End-fed antennas are quick to pack up as they have little if any coaxial feedline.
* Light masts supporting little weight also don't require guy wires. Another time-saver.
* Choose a site with metal, such as jetties or fences, to clip on to for your earth system. That saves energy carrying and time in rolling out wire radials.

As you've probably seen from my videos, a good combination that meets all the requirements for a quick portable antenna is an end-fed wire (approx 20m long) supported by a 9m telescoping fishing pole. An antenna coupler allows operation on multiple bands between 7 and 28 MHz. 3.5 MHz is also possible but efficiency is poor unless you have a good ground system. Or, if 7 MHz isn't required you could just use the pole to support a vertical.

Three minute portable antenna

Two minute portable antenna

Have any other time-saving portable antenna ideas? Please leave them in the comments below.

PS: Want to get more from amateur radio? These books written by Peter Parker VK3YE could be of interest. Available in electronic and paperback form (some countries) they have proved popular among amateurs worldwide.

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