You need to do two things.
1. Make it slightly shorter, to move the resonant frequency from nav (113 MHz) to com (127 MHz), or about 10%. E.g., cut about 2.5 - 3 inches off the end of the radiating element. Ideally you do this a little at a time, while monitoring the resonant frequency with an antenna analyzer, but this will be close.
2. Most important. Someone already mentioned polarization. In theory the antenna will not work at all if it’s horizontal. You want get as much vertical throw as possible in the leading edge (the diagonal part going from the ground leg on the rib, out into the wing). This is where most of the signal comes from. Since most wing tips are not symmetrical up-down, look at yours and see how to do this. I have stock -10 tips. I mounted the ground leg of the antenna to the end rib as high as I could, near the top. The leading edge of the radiating element, extending out into the tip, is bent down, until the long side is resting on the bottom of the tip.
This is not as good as an external, vertical antenna, but better than some believe. I have no problems at 20 miles. I use it mainly for atis, sometimes ground.
Edit. Also, don’t mount the antenna near the front of the tip. Mount it close to the ‘fattest’ (up-down) part of the wing, again, to maximize the vertical distance you can get.
Last edited by BobTurner : 09-26-2023 at 07:31 PM.