Interference on both comm radios near airports

[rbmaze]

When I am flying around airports in urban areas the squelch on my comm radios opens and I get a lot of static. I have no problem hearing real transmissions and as soon as someone transmits I can hear loud and clear but then it goes back to static. It is present when flying the pattern at some airports (KMYF, KSEE). At KMYF I think it starts when I'm about 50ft AGL.

Initially I was thinking the squelch on my radio needs to be adjusted, but it actually happens on both my GNS 530W and SL-30, though it's worse on the 530W so I typically use SL-30 as my primary.

I would like to get this fixed, but I am afraid of opening an expensive project. Maybe the coax or antenna needs to be replaced, but since I only get this in the air I am unsure how to reproduce and debug on the ground.

Anyone have experience with something like this?

[EricJ]

That just sounds like the squelch needs a small adjustment.    There is likely to be a bit more noise/interference around an airport or urban areas, so that may be what is making it break squelch.    If it only does it at that particular location, it's probably a particular interfering signal that is doing it.   It might be a tradeoff between living with it so that you have more sensitivity elsewhere or suppressing that particular issue.   Autosquelch these days is usually pretty good, but I don't know whether that is available on a 430 or your other radio.

[PeteMc]

Yep, what @EricJ said and why you have the Squelch option on the radio.  

Adjust the Squelch setting just a touch to get rid of the noise.  Then those times you can't hear the ATIS at a distance or whatever, you still have the Squelch option so you can hear everything. 

 

[N201MKTurbo]

Try powering down the radios individually and see if the other radio behaves properly. It could be interference coming from your radios.

[M20F]

1 hour ago, N201MKTurbo said:

Try powering down the radios individually and see if the other radio behaves properly. It could be interference coming from your radios.

I would go one step further which is pull and check each breaker.  123.0 my radios sound awful if my WX-900 is on as example. 

[rbmaze]

Thanks for the tips! I did think it was squelch until I realized both radios do it, but I confirmed they have different levels of interference.

Took a look at the radios and the SL30 seems easy to change. 530W I pushed some buttons and turned knobs and can see the RF squelch setting, but cannot seem to save it. I would guess it's locked down, but any tips appreciated .

[LANCECASPER]

27 minutes ago, rbmaze said:

Thanks for the tips! I did think it was squelch until I realized both radios do it, but I confirmed they have different levels of interference.

Took a look at the radios and the SL30 seems easy to change. 530W I pushed some buttons and turned knobs and can see the RF squelch setting, but cannot seem to save it. I would guess it's locked down, but any tips appreciated .

From the GNS530 Pilot's Guide:

Overriding the automatic squelch: 1) Press the COM Power/Volume Knob momentarily. 2) Press the COM Power/Volume Knob again to return to automatic squelch operation.

At least that would allow you to check it to see if that's the problem.

[Ragsf15e]

7 hours ago, N201MKTurbo said:

Try powering down the radios individually and see if the other radio behaves properly. It could be interference coming from your radios.

This could be frequency dependent too.  Definitely try turning off a radio and fly that way for a while to see if it changes behavior.  

[MikeOH]

1 hour ago, rbmaze said:

Thanks for the tips! I did think it was squelch until I realized both radios do it, but I confirmed they have different levels of interference.

Took a look at the radios and the SL30 seems easy to change. 530W I pushed some buttons and turned knobs and can see the RF squelch setting, but cannot seem to save it. I would guess it's locked down, but any tips appreciated .

After you push the VOL/SQL knob and SQUELCH appears, THEN turn the knob clockwise until the noise stops, then push the VOL/SQL knob, again which will return to AUTO but with the new threshold set.  As others have pointed out, there is likely some high level interference in your area so this new setting may inadvertently now suppress lower level transmissions you may WANT to hear in other locations; that's the drawback of a high squelch threshold setting.

[takair]

As I recall, there are further adjustments in the maintenance menus. 
 

As others suggested, be sure it is not only specific frequencies. Also, check basic things like turning off other systems. USBs can be problematic and only show up on certain frequencies. Add in local noise and it can open the squelch. 

[rbmaze]

4 hours ago, LANCECASPER said:

From the GNS530 Pilot's Guide:

Overriding the automatic squelch: 1) Press the COM Power/Volume Knob momentarily. 2) Press the COM Power/Volume Knob again to return to automatic squelch operation.

Right but this will allow one to listen to all signals, holding open the squelch. Maybe my squelch control is stuck in full open and not automatic.

3 hours ago, MikeOH said:

After you push the VOL/SQL knob and SQUELCH appears, THEN turn the knob clockwise until the noise stops, then push the VOL/SQL knob, again which will return to AUTO but with the new threshold set.  As others have pointed out, there is likely some high level interference in your area so this new setting may inadvertently now suppress lower level transmissions you may WANT to hear in other locations; that's the drawback of a high squelch threshold setting.

This is news to me but would be great if true. Will give it a try.

The Pilot's Guide does not describe this behavior on the 530W and only says the Squelch control disables automatic squelch.

The COM radio features an automatic squelch to
reject many localized noise sources. You may override
the squelch function by pressing the COM power/
volume knob. This facilitates listening to a distant sta-
tion or setting the desired volume level.

To override the automatic squelch, press the
COM power/volume knob momentarily. Press COM
power/volume knob again to return to automatic
squelch operation.

 

[MikeOH]

@rbmaze

9 minutes ago, rbmaze said:

This is news to me but would be great if true. Will give it a try.

My bad; I should know better than trusting AI.  Looking deeper that answer is for a Garmin MARINE radio!

It does look like you need to enter maintenance mode by holding down the ENTER key when turning on power.  There is supposedly a setting for squelch threshold.

I'll understand if you don't trust me on that one! 

[rbmaze]

7 minutes ago, MikeOH said:

@rbmaze

My bad; I should know better than trusting AI.  Looking deeper that answer is for a Garmin MARINE radio!

It does look like you need to enter maintenance mode by holding down the ENTER key when turning on power.  There is supposedly a setting for squelch threshold.

I'll understand if you don't trust me on that one! 

All good .

I entered maintenance mode and saw that I can change the squelch, but unfortunately cannot save it. I read that there are three specific frequencies, and only these three, that can be saved without having maintenance/dealer access. I could see if my A&P can save it for me, but the problem is I don't know what value I want without flying around my pattern, so I may just use the SL30 since it's pilot updatable.