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Back-Up Radio Solutions?

n74846

Well Known Member
My SL-40 died and is at Garmin for overhaul. My Icom A-6 is barely useful with the tower with the stock antenna. Has anyone found a successful solution to deal with the single radio failure scenarios? If you have added a switchbox or other jury rigged antenna, please describe. Thanks!
 
I can get about 5 miles out of mine in a high wing using the rubber duck. There is a high gain antenna that works in the aviation frequency that I have seen used before. Not sure how much more reach you get. With the low wing your best bet is probably a belly antenna or a t connector on your existing antenna with a pig tail.
 
It is my understanding that you cannot simply install a T-connector in the antenna line. Either install a separate belly antenna with a dedicated cable to use with your hand-held or install a special switch that selects one radio or the other for your one antenna -- King Avionics used to sell such a switch.
 
I had a spare Microair 760 from another project so I installed it in the panel as comm 2. It has a separate antenna I mounted on top of the fuselage and the audio-in is wired through my intercom with independent jacks as a backup.
 
I've always used a separate external antenna with a coiled antenna wire near the seat cushion that can easily be connected to my Icom handheld. Also used a Icom headset adapter and was good to go. Has come in handy a couple of times when I developed trouble with my panel mount com.
 
Poor man's solution: bring the antenna coax to a panel BNC. Bring the radio coax to another nearby BNC. Jumper the two BNCs with 8" of coax. If main com fails unplug the jumper from the radio, plug into the handheld.
 
The only time in 31 years of flying that my radios went out was, of course, the day I forgot my handheld. The tower guys loved it because they never get to use the light gun.
 
Thanks to all for their input. Still trying to figure out how to route either the switchbox, or add another separate antenna for the handheld.

Interestingly I searched the web regarding the Icom A-6 headset adapter problems I've been having and found an interesting thread. While I have not had time to check it out in the plane, apparently the adapter DOES NOT kill the handheld mic in lieu of the headset mic. Hence if I do not talk into the handheld instead of the headset mic, I cannot be heard; which is exactly what I am experiencing. A bizarre quirk of the Icom headset adapter, but might be my big problem. The solution, according to the thread (and quoted from Icom Support) is you must use the auxiliary PPT switch they sell, which plugs into the third plug on the adapter. Only then does the headset mic engage. Who knew?
 
My plane has an unused VOR antenna since I don't have a NAV receiver. I ran the coax from that to a BNC bulkhead fitting in the panel. In a pinch, I can connect my handheld to that with a short piece of coax. Yes, I realize the VOR antenna is horizontally polarized and COMM antennas are vertically polarized, but it seems to work. Also, I have a headset adapter for my Icom handheld so I could still use my headset (noisy cockpit).
 
Be aware that those 'switch boxes' can be built with about $10-$15 in parts. They consist of a pair of BNC bulkhead females and a 1/8" 'normally closed' jack, like what you'd find in a 'boom box' with an external speaker jack. While they will work fine, they will almost always destroy your carefully set up SWR (if you sweat that).

The simplest, lowest loss, cheapest, and most reliable method is just a bulkhead mount BNC female on the end of the a/c antenna cable, and a male/male cable from the panel mount radio. Mount the BNC female where it's in reach (near the bottom edge of the panel usually works), and if the panel mount fails, unhook the coax from the panel mount and attach the coax from your handheld.

Did I mention that all this stuff has been covered ad nauseam on the Aeroelectric list, and I'm pretty sure it's in 'the book'. You do have the book, right?

Your issues with Icom is an example of why I'm not much of a fan of their stuff. ('It's not a bug; it's a feature....')

Charlie
 
Do your self a favor, add a separate antenna. Nor worries about interference or signal loss with connections to your main radio. A dedicated antenna is worth it. I've had them on 2 aircraft in the past and am planning to add one to my next one.
 
Do your self a favor, add a separate antenna. Nor worries about interference or signal loss with connections to your main radio. A dedicated antenna is worth it. I've had them on 2 aircraft in the past and am planning to add one to my next one.

An alternative is to mount your com radio (if it is a remote unit with a small panel mounted control head) so that you can easily access the coax connection in flight.
I have the one in my RV-6A mounted this way and I carry a 3' long coax extension to connect it to my hand held if my primary radio fails.
 
I've got the stock E-LSA configuration with the SL-40. Hence I cannot reach the panel antenna without messing the paint, panel or instrument access.

A a further note,Icom finally called back yesterday and in fact confirmed(after further checking) that the mic issue is a hidden 'feature', not a bug. Not anywhere in their literature, but will be now that they have confirmed this added 'feature'. 😂
 
In a situation with a total radio failure and all else is working fine... wondering how well a hand held would get out using the ELT's antenna cable connected to the hand held?

On the RV-12 (original version) the excess ELT antenna wire is tie-wrapped to the body of the ELT unit which is behind the passenger seat. The ELT is reachable (I think) and it may be doable to disconnect the BNC connector and move the ELT's antenna cable over to a hand held. Also it may even be easier to run a short antenna cable from the hand held directly to the connector at the base of the antenna (which if memory servers me also has a BNC connection).

Just curious if anybody has tried this in a pinch? If so, did the ELT's antenna perform better than the typical antenna that comes with the hand held?
 
Messing with the aircraft radio antenna cable could cause an eventual radio failure that would not occur without the handheld radio installation. It is better to use a separate, independent antenna, external or even within the cabin.
Radio problems are just as likely to be caused by a bad antenna or cable as by failed electronics. The backup radio should be completely independent.
 
Has anyone had success with the suction-cup antenna extension?. I've heard they do not enhance reception distance over the rubber ducky. Sounds like a good investment to simply add a second comm antenna for back up.

Would an inactive second antenna interfere with the active comm antenna co-located on the belly?
 
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