Noisy radio

[ragedracer1977]

My Nav/Comm 2 has some issues.  Whether there is any transmission or not, switching to com 2 on the GMA-340 is immediately 'staticy'.  I can transmit and receive, but it's very difficult to hear what's being said, due to the static.  It's a Narco NCS-812 - similar to the MK-12, but with DME capability - although I don't have DME because it doesn't have the upgraded VOR indicator.  Also, I noticed that to identify the VOR, I can't push Nav 2 on the GMA-340, I have to push com 2 (this seems like it might be normal as the manual says the nav and com share an output).  It does receive the navigation information, etc. but it's mostly useless as a com because of the static.  There is no squelch control.

Does this sound more like the radio going bad or a bad connection somewhere?

[Marauder]

My Nav/Comm 2 has some issues.  Whether there is any transmission or not, switching to com 2 on the GMA-340 is immediately 'staticy'.  I can transmit and receive, but it's very difficult to hear what's being said, due to the static.  It's a Narco NCS-812 - similar to the MK-12, but with DME capability - although I don't have DME because it doesn't have the upgraded VOR indicator.  Also, I noticed that to identify the VOR, I can't push Nav 2 on the GMA-340, I have to push com 2 (this seems like it might be normal as the manual says the nav and com share an output).  It does receive the navigation information, etc. but it's mostly useless as a com because of the static.  There is no squelch control.
Does this sound more like the radio going bad or a bad connection somewhere?

Having dealt with my fair share of radio noise over the years, the root cause could be a number of things. I would start with the basics. Pull the radio, clean the contacts using a good electronic cleaner. Check the connection for the com side to make sure the cable is securely attached. If you can get access to the antenna, check the connection there as well.

If the radio static is fairly recent, make sure you check if you added anything new in the way of electronics (chargers, etc). Also try turning non essential electrical stuff off to see if it improves.

I had issues with a new JPI 900 causing one problem. Also had a bad antenna cause another issue. I eventually had enough and pulled all my plane’s original RG-58 coax cable and replaced it all with RG-400. Made a world of difference. Also found that the RG-58 had worn through the insulator in a few places and was compressed in other places.


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[PMcClure]

I just found my static problem on Radio #1 was the iPad charger.

[ragedracer1977]

43 minutes ago, Marauder said:

 

Having dealt with my fair share of radio noise over the years, the root cause could be a number of things. I would start with the basics. Pull the radio, clean the contacts using a good electronic cleaner. Check the connection for the com side to make sure the cable is securely attached. If you can get access to the antenna, check the connection there as well.

If the radio static is fairly recent, make sure you check if you added anything new in the way of electronics (chargers, etc). Also try turning non essential electrical stuff off to see if it improves.

I had issues with a new JPI 900 causing one problem. Also had a bad antenna cause another issue. I eventually had enough and pulled all my plane’s original RG-58 coax cable and replaced it all with RG-400. Made a world of difference. Also found that the RG-58 had worn through the insulator in a few places and was compressed in other places.


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The static has always been there as long as I've owned it.  It occurs even on the ground with out the engine running and nothing in the plane on but what has to be on.  I would say the static has gotten worse, though.  Is there a way to easily determine which antenna it is?  For notation purposes, the 430 is crystal clear.

 

[Marauder]

The static has always been there as long as I've owned it.  It occurs even on the ground with out the engine running and nothing in the plane on but what has to be on.  I would say the static has gotten worse, though.  Is there a way to easily determine which antenna it is?  For notation purposes, the 430 is crystal clear.
 

Based on what you described, I would start with cleaning the connector on the back of the radio. My Narco was notorious for having issues there.

As for the radio antenna location, most Mooney’s have them located on top. Most forward is usually the Com 1 radio’s antenna. If you clean the connector and check the antenna connections, I think the next easiest thing to do is try to find someone who has the same radio and slide it in. If it is a radio issue, there aren’t many places still working on them due to parts availability. I eventually removed mine and went with a GNC 255B from Garmin.


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[takair]

The volume knob should double as a “test” or squelch when you pull it out.  Does your radio have this?  Does it make a difference in or out?

[ragedracer1977]

3 hours ago, takair said:

The volume knob should double as a “test” or squelch when you pull it out.  Does your radio have this?  Does it make a difference in or out?

Yes, the static gets worse pulled out.

[1964-M20E]

there is a place in NJ I think that still repairs these radios.  There is also source for the display if you are having issues with that as well do a search on MS I posted the source a few years ago.  Easy to change and not that expensive.

 

Check the connectors at the back of the tray.  On my 812 the VOR will act up from time to time. 

[EricJ]

Could be a bad connector.    As mentioned try to clean up what you can get to and see if that helps.    If either of the antenna connectors are accessible cleaning them up can help (rather than try to sort out which is which, just clean the one you can get at).

 

[Ned Gravel]

Narco radios are notoriously noisy in that their internals are not as well shielded as they might be for the panel environment.  To make matters worse, Garmin does not do a very good job of shielding their internals from EMI.  I solved my problem by replacing my GMA 340 with a PS 8000.  It did not matter after that how noisy the radios were.  The PS 8000 filtered it all out.

[ragedracer1977]

I flew an instrument XC today and we used it for getting ATIS and nav functions.  It wasn't so bad way up in the air today.  I'm going to pull it out and clean the connectors.  Also, I see I have 2 comm antennas on the roof.  One is pretty new looking (been replaced since the plane was painted 12 years ago, I can see the old paint lines).  I'm guessing the older one farther back is the Comm 2, but who knows.That antenna (the one farther back) is corroding at the mount part (the cast aluminum base) and the paint is flaking.  Could it be just that there's some corrosion in it causing problems?  The one farther back I should be able to access through the tail access panel and clean the connection, the other appears to be right above the cabin speaker so I might be able to access the connector there without having to pull the whole headliner out.  

[carusoam]

If you can see the tuning knobs from the inside... Do they look like variable capacitors? (Layered interlocking discs(?)) they make great variable noise makers as the dust moves from one disc to the next...

Fair warning... I’m still bitter about my C's Narco radios. One needed a 50 Cent plastic gear, they wanted $50 to tell me it needed the gear.

They closed shop with my radio still on their shelf.

Had they just sold me the gears, I'd be telling a great story now...

Plastic gears and old vehicles don't go so well together...

Best regards,

-a-

[Marauder]

I flew an instrument XC today and we used it for getting ATIS and nav functions.  It wasn't so bad way up in the air today.  I'm going to pull it out and clean the connectors.  Also, I see I have 2 comm antennas on the roof.  One is pretty new looking (been replaced since the plane was painted 12 years ago, I can see the old paint lines).  I'm guessing the older one farther back is the Comm 2, but who knows.That antenna (the one farther back) is corroding at the mount part (the cast aluminum base) and the paint is flaking.  Could it be just that there's some corrosion in it causing problems?  The one farther back I should be able to access through the tail access panel and clean the connection, the other appears to be right above the cabin speaker so I might be able to access the connector there without having to pull the whole headliner out.  

If you want to know for certain if the rear antenna is connected to Com 2, remove the BNC connector for the rear antenna and from the radio. Place a piece of aluminum foil across the inner conductor and the outer connector. Then from the opposite end, check to see if you have any resistance if an ohm meter between the inner conductor and the outer connector.


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[ragedracer1977]

So, it turns out my radio is just fine.

@N201MKTurbo is a genius, or I'm a moron.  Not sure which, but I'll go with the former for now.

First, let's note that I said 'it's been getting worse.'  Next, let's note that I've posted several times lately that I'm using my plane training for my Instrument rating.  Finally, let's note that I stated that on the audio panel, the audio for the nav comes through on the same 'channel' as the voice.

I went down and saw Rich last night.  He sat down in the plane and had me fire up the radios.  Sure as can be, very staticy.  He says "Let's try turning down the nav volume on the radio."  Static instantly gone.  

So... What had happened was - as I was training for my IR, my instructor has been drilling very hard to listen for the morse.  So, of course, I had to turn up the volume on the nav side.  Now, since the audio from the nav comes through the comm, and it's open squelch... Static.

Thanks Rich! 

[Skates97]

I had something similar happen. I was getting a whining in my headset. I ended up that the volume on my radio was turned down too low and the volume on my Halo's was turned up too high. I started playing with the volume on the Halo's and it went away, then turned up the radio a little and it was perfect... 

[Marauder]

So, it turns out my radio is just fine.
[mention=7464]N201MKTurbo[/mention] is a genius, or I'm a moron.  Not sure which, but I'll go with the former for now.
First, let's note that I said 'it's been getting worse.'  Next, let's note that I've posted several times lately that I'm using my plane training for my Instrument rating.  Finally, let's note that I stated that on the audio panel, the audio for the nav comes through on the same 'channel' as the voice.
I went down and saw Rich last night.  He sat down in the plane and had me fire up the radios.  Sure as can be, very staticy.  He says "Let's try turning down the nav volume on the radio."  Static instantly gone.  
So... What had happened was - as I was training for my IR, my instructor has been drilling very hard to listen for the morse.  So, of course, I had to turn up the volume on the nav side.  Now, since the audio from the nav comes through the comm, and it's open squelch... Static.
Thanks Rich! 

You’re living proof, that overlooking a simple detail can be a root cause. Glad it was something easy to resolve.


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[EricJ]

I bought a new headset and had a little trouble until I sorted out the mic sensitivity was a lot different than the previous one and I needed to turn the mic squelch down.   Glad you got it sorted!   Rich is definitely the man.

[Stanton R]

Your audio panel or 812 is wired wrong. The 812 has a dedicated nav audio output and shouldn't be on the com2 switch.

[ragedracer1977]

Interesting.  I was looking at the manual and could only see one audio out.  Upon further reading, it looks like you're right.  I'm going to want to get that fixed.  It's annoying.

[Stanton R]

Whoever did the installation may have hooked the nav audio out to the aux audio in on the 812 which would put the nav audio on the com audio output.

[bradp]

It’s kind of similar to me wondering why I could always hear frozen music playing through my headset and my copilots mic when my daughter was watching an iPad.  Turns out someone had wired the rear pax mic and audio commons together.  

Theres usually a resason for the gremlins it’s just finding it that’s the challenge. 

[Skates97]

2 hours ago, bradp said:

It’s kind of similar to me wondering why I could always hear frozen music playing through my headset and my copilots mic when my daughter was watching an iPad.  Turns out someone had wired the rear pax mic and audio commons together.  

Theres usually a resason for the gremlins it’s just finding it that’s the challenge. 

I may have to check into that. If my son has his music plugged into his headphones I can hear it. I currently just have him out ear buds in underneath his headset now. 

[kpaul]

2 hours ago, bradp said:

I could always hear frozen music

 

16 minutes ago, Skates97 said:

If my son has his music plugged into his headphones I can hear it

Ah, the beauty of Bose and Bluetooth A20s.  My daughter watches movies, listens to music and I don't have to hear any of it.