Crackling on Reception

My 430W has worked very well over the last 6 months, however, just recently I started getting some crackling/interference on almost every reception. The range is still solid and have experienced no issues receiving any transmission, including enroute center frequencies over x-country. There is an occasional transmission that comes in without the crackling, but it is rare. The crackling is not enough to prevent hearing the transmission, but it is annoying. I have not yet asked if there is a problem with my transmission, but have not heard a single complaint from ATC or other pilots. The squelch has never been broken from this and I have noticed it happening when I know that I am close to other planes or a tower. Though it is universally less severe when close.

My other radio (KY-96) does not exhibit this behavior, but I don't like using it as it has no sidetone and I don't like not hearing my voice on transmissions (I haven't really dug into why it doesn't work as it is my backup and don't transmit on it much).

I flew through the rain the other day and I think this is when it started. However, I don't believe that I get any leakage in the area of the 430W and had no other issues with the radio, including shooting an approach with it.

I am currently thinking it's an antenna ground issue, but haven't really dug into it yet. I re-torqued all of the bolts during my condition inspection a couple of months ago.

I will swap antenna's before my next flight to see if the problem follows it.

I appreciate any guidance from the experts.

Larry

lr172 said:

I am currently thinking it's an antenna ground issue, but haven't really dug into it yet. I re-torqued all of the bolts during my condition inspection a couple of months ago.

Click to expand...

I agree that it sounds like an antenna ground issue, but I would suspect the cable ends more than the antenna itself. Make sure that the shielding is making good contact with the connector.

ignition wires? Loose connection?

Could be wires - I know it is on mine - but it's not bad enough to spend an AMU on new wires & plugs. I'll change to auto plugs when this set wears out, and change to plug adapters and auto wires at the same time.

Made up as many as I could on the new build today (ran out of wire - ordered more), so now I know how to make the best wires available (MSD 8.5mm) - why buy the overpriced aviation stuff?

How do I know it's wires on my bird? The crackle follows the engine RPM...

Might check your plug/wire connection for tightness, and inside the plug top end for contamination too.

Best,
Mark

F1Boss said:

Could be wires - I know it is on mine - but it's not bad enough to spend an AMU on new wires & plugs. I'll change to auto plugs when this set wears out, and change to plug adapters and auto wires at the same time.

Made up as many as I could on the new build today (ran out of wire - ordered more), so now I know how to make the best wires available (MSD 8.5mm) - why buy the overpriced aviation stuff?

How do I know it's wires on my bird? The crackle follows the engine RPM...

Might check your plug/wire connection for tightness, and inside the plug top end for contamination too.

Best,
Mark

Click to expand...

Bingo!!! Thank you!!

I have one EI and was running the Autolite 386 plugs (only 18mm plug with a resistor). While I had no problems, I felt that the plugs were too hot (ceramic cones were running a bit too white for my comfort) and decided to try the NGK AB-8's. Those are non-resistor plugs, so I bought new connectors that had the 5K resistor in them. I made this change before my last flight and forgot that when trying to find reasons for the noise.

It is possible that I didn't get the connectors on properly (They have a screw in design instead of crimps) or they simply aren't a reasonable alternative to resistor plugs for eliminating noise. However, all plugs are firing and still able to run 100 LOP without issue, so probably not a botched installation.

I feel so foolish for not remembering that I made that change when trying to figure this out.

Thanks again and I'll post the final results on this plug configuration, as it represents a good option to avoid those 18 - 14mm bushings.

Larry

Had a 4 hour flight today. In flight I killed the EI and the problem vanished. I guess the idea of resistor caps as a substitute for resistor plugs is a fantasy.

Larry