Can anyone provide suggestions on fabricating an extension antenna for an aviation VHF handheld (in my case a Yaesu VXA-100)? I recall that we used to fab a "half-rhomboid" antenna from commo wire for our PRC-77 radios that significantly extended range over the whip antenna. I have in mind using the short whip in the air and deploying the extension on the ground if forced down over land. Thanks!

These links may help you out<br><br>http://www.arrl.org/tis/info/pdf/0791033.pdf<br>http://www.arrl.org/tis/info/pdf/ab18-16.pdf<br><br>They are from the American Radio Relay League website and describe how to build very simple antennas called "groundplanes". You can get all the parts at any Radio Shack and assembly time is less than an hour.<br> The end product can then be balled up and packed with a length of coaxial cable and some fishing line.<br> To use the antenna just staighten the wires, hoist it into a tree with the line and plug your radio into the coax. <br> It will perform much much better than a rubber duck antenna.<br><br>Chris

Thanks, Chris. I downloaded the pdf files; the only question that I have now is whether the 146 MHz antenna is optimal for aviation comm frequencies or how to calculate those dimensions. If I had to pick a frequency to optimize, I guess it would be 121.5, close enough to ARTCC frequencies I assume to offer better performance than 146. On the other hand, maybe it doesn't matter that much.<br><br>Bruce

There is freeware / shareware / open-source software available that can help you to design antenna systems. One such source is listed below but there are others. ARRL is a good place to start searching though I came up with this link from a Google search. If this software is confusing to understand then feel free to lean on a local HAM operator or the helpful folks at ARRL in CT.<br><br>http://www.myerseng.com/

Bruce:<br><br>I thought the second .pdf had a formula for determining lengths but it may be confusing. If you want to adapt the first antenna to that frquency you can contact the ARRL lab at tis@arrl.org. Just reference the article and let them know what you are attempting to do. They are a real friendly bunch who love a challenge. <br> The advice from Mebrad about the software or contacting a local ham radio club is good too. There is a lot of hams who are pilots and they could probably whip one of these up for you without a problem from there own spare parts. You might even get into the hobby yourself.<br><br>Good Luck<br><br><br>Chris