Antenna Shootout, UHF Edition

We’re at it again! Before the August 17 meeting, we invaded the large parking lot we use as an antenna test range once again. This time, we brought UHF antennas, and found that despite their smaller size, they were all very efficient. Don KB3LES brought his double diamond array, which may be small, but packed a big punch! Lars KB3WBT ran his Quagi through its paces, and Joe W3BC made reference measurements of his Rover Yagi.

The antennas all performed so well it was too close to call. Don’s antenna had high gain, and it was in almost all directions, Lars’ quagi had deeper side nulls, but was still “lobey” off the back. Joe’s Rover antenna had plenty of forward gain, but when as little as 15 degrees off the target, the signals went away and stayed away.

Don’s antenna had the smallest turning radius, and its wide beamwidth and high gain is perfect for net and repeater operations. It would be particularly well-suited to talking to mobiles, since its wide-pattern coverage would blanket an area better than any other antenna we tested. Plus it was the most unique looking of the bunch! Lars’ quagi was very lightweight being made of PVC pipe, and was easily portable. It would make a great antenna for working distant repeaters. Joe’s Rover antenna was showing the effects of bouncing down hundreds of miles of back roads on countless contest roving missions. A couple of the elements were loose, and could be heard and seen on the receiver as they flopped around in the breeze. It certainly meets its design requirement of hearing only what it’s pointed at, and rejecting strong contest QRM from off the sides and back. Mechanically though, it needs some maintenance before it falls apart, and perhaps a sturdier redesign to keep the elements where they belong.

The exercise could be called a “quest for truth” and there were many truths revealed, even by the simplistic testing methodology we used. Given more time, and more attention to little details, some very accurate results could be obtained, but in our assembly-line session, we learned a lot, and got a good idea of the performance of each antenna under test. We will add these techniques to our inventory, and we’ll certainly be doing more antenna testing in the future.

After we ran out of UHF antennas, we switched the remote transmitter to VHF, and tested Lars’ latest creation—a 5 element two meter antenna that uses metal arrow shafts for elements. It is a clean-looking antenna, and initial test results showed it to have good gain and a very smooth pattern. After twirling it around the compass and recording received signal strengths, we gave it a real test—we dialed up a distant beacon and pointed the antenna its way.

Sure enough we heard a carrier, and then the CW id of WA1ZMS on 144.285 MHz, located on a 4200 foot mountaintop in Virginia, some 253 miles to the south!

The net result was that all the antennas were winners! Every one of them had plenty of gain to pick up the weakest signals, while the off-axis signal sensitivity or rejection differed, making each antenna suitable for a different purpose. That diversity is what makes Amateur Radio so much fun, and gives us choices to meet our operating needs.

Not to mention that everyone there had a lot of fun!

       

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1 comment to Antenna Shootout, UHF Edition

  • Lars

    This would be my all time favorite! To build an antenna, that you might have an idea will work in a certain way, and it really does! If you then add a couple of your own tweeks, to see if it got better, takes a week signal in the distant, so a beacon is a really big help!
    I certainly will try to make that happen in our area too!
    Lars

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