I'm having an issue with some handheld transmitters, and not sure if they're bad, or the newly-installed antenna is bad, or if this even makes sense.
I've been using a handheld Icom aviation radio (model A23) within a hangar (ie, a metal-skeleton building) without any specific issues. We installed a base station antenna (B-ANT) with the hopes of being able to get better range from the handheld. The handheld was plugged in via an adapter cable and suddenly started transmitting intermittently. By that, I mean that when depressing the PTT the received audio sounded as if the PTT was being rapidly pressed and let go, at a rate of about 5hz. Additionally the red LED "RX/TX indicator" flashed at the same rate. In fact, I thought that it might be a bad PTT switch.
What's weird is that this continued even when the external antenna was removed and the stubby antenna was replaced when the handheld was in proximity to the antenna cable. It happened consistently when within a foot of the antenna cable, but only began consistently working properly when > 20 feet from the antenna cable.
This happened from a second Icom handheld radio.
It did not happen with a Yaesu handheld aviation radio, even when that radio was connected directly to the antenna.
What's happening here?
I can't find an impedance rating for the antenna, but it's specifically recommended for some of their base stations (e.g., the A110), which have 50ohm impedance. Their handhelds (e.g., the A24) also have a 50ohm impedance.
I did find a spec sheet for the antenna if that's relevant.
While this antenna is sold with the base station radios, I haven't seen it recommended for handhelds; I assumed that's mostly just a function of not a lot of demand for external antennas with handheld tranceivers.