The Panel Planner 101 feature on replacing old antennas (January 2025 Aviation Consumer) generated a handful of letters from readers who were not only glad they replaced their decrepit antennas during avionics upgrades, but also from a few who went the extra distance and installed backup antennas. Specifically, an auxiliary comm antenna for connecting to a handheld transceiver. The investment could be a lifesaver.
“I had over $80,000 invested in my new Dynon HDX package but it didn’t do me much good when I had a total electrical system failure at night over some rough terrain,” one reader told me. His airplane not only had the integrated Dynon comm radio but also the one that’s built into the Avidyne IFD440 navigator. But without electrics, neither did him any good.
And while he had an old Icom transceiver in his flight bag (with dead batteries—another lesson), it likely wouldn’t have been much use because the portable whip antenna on all portable rigs generally won’t provide much transmit performance beyond the local traffic area.
An easy solution is to have the shop install an inexpensive auxiliary comm antenna on the belly of the aircraft and route a piece of coaxial cable up into the cockpit. Since most portable radios have a BNC antenna connector (accessed by unscrewing the portable whip antenna), simply attach the coax cable to the radio and there’s a good chance you’ll transmit and receive far enough to get back on the ground. With a headset adapter, it’s even more seamless. When the aircraft is opened up for other work, the install might be a $500 investment or less.
Another option is the Icarus EXTenna switch shown below. Sporty’s sells it for $130. It’s essentially a splitter/switcher that allows an existing comm antenna to be shared with a panel radio and a portable. When you plug the portable in (using the supplied cable with a 3.5 mm male connector), the panel comm radio is disconnected and the portable is connected from the antenna. But use caution not to key the disconnected radio—it can be damaged without an antenna load on it.
The splitter can fit in an existing round 2.25-inch instrument hole or it can be installed wherever there’s space on the panel. Find it at www.sportys.com.