I have a 60' 172A with some radio issues. I have a King KX-175B, an a Narco 11A. The Narco seems to work ok, but the King works good one day and then terrible the next. I have pulled them out of their trays, and cleaned the contacts, but the problem seem to be getting worse. Also, I was told that my transpoder was not giving my altitude. Oh ya, I have replaced the Narco with a different 11A.

Any help would be greatly appreciated!

First off you need a certified radio shop to fix those radios to make them legal. Sometimes the problem is a bad ground on the antenna or simply corrosion in the wiring. How old are the radios and how long since they have been checked? Aircraft radios are very prone to installation and corrosion problems especially if kept in damp climate. Norm

Thanks for your response!

The King was rebuilt in the mid 90's, and the Narco was tested in another plane, and works fine. The plane is hangered. I have looked at the contacts, and bnc connectors for the antenna's, but I must admit that I get lost in all of that wiring..... The connectors seem to be in good order....

I will check over the antenna mounts, and wiring this weekend.

Thanks!

Hi Sometimes when you are dealing with old radios in an older aircraft and you are not going to use the aircraft for IFR work then you might consider a high end portable to use in dealing with towers and Unicom advisories. The new portables are quite good and are available in all configurations. It could save you big bucks and your neck as well. Norm

Thanks!

I have a hand held that I keep in my Flight bag. I have the head set adapters for it, and keep it in the plane for an emergency. I do fly mainly VFR. I live in the mountains and enjoy hopping from one little grass strip to another. It is just occasionally I need to go through or near ATL, and deal with ATC sometimes.

I am IFR certified, and have my commercial ticket. My plane is not IFR certified. I am afraid it would cost way to much to change that!

Thanks for your Help!

You're welcome. I just retired a few months ago as Editor of Private Pilot magazine for the past 9 years. Having an aircraft with good radios is so great. After the war I flew so many surplus military planes that had junk or most of the time no radios at all that I have come to appreciate good radios. I was a Cessna and Piper dealer for 10 years and owned all new airplanes with state of the art radios and then for the last 10 years I have been testing new airplanes. I would have a very hard time going back to planes with older radios. Youngest son Robert is Senior Editor of Flying Magazine and he is also the avionics editor. Have fun with your 172, one of best airplanes and safest every built. Norm

Older radios often have the problems you are reporting caused by dirty or corroded connections inside the radio. I have seen this time and time again. Your best bet would be to send it in to a radio shop for a checkout.