Engine Noise Through 2M Speaker

[NorCalLC]

Hey all, I have an older ICOM 2100 and I'm getting engine whine through the speaker. It's only when I have numerous things on (headlights, heater, rear window defrost etc.) I'm thinking it's my alternator and I'm looking for a used 90 amp to rebuild. When all the items above are on it's a real pull on the elec guage and I can see my lights dim a bit.

Now to my question, I know of filters to put in line that are able to clean that up but I'm wanting a bit more input from the "experts" on this problem before I just throw money at it. BTW, I have it hooked up per the manual, directly to the battery with fuses at the ends by the battery. No other issues with the radio but that.

Thanks for any help in advance.

 

[4RunAmok]

OEM-T Connector http://www.powerwerx.com/oem-connectors-filters/dc-line-noise-filter-oem-t.html (The image is broken, but the "view a larger picture" works)

Anderson Powerpole Connector http://www.powerwerx.com/oem-connectors-filters/dc-line-noise-filter-powerpole.html

Sometimes this can be caused by a ground loop, or you could have something wrong within the alternator.

Good article on Ground loops and hums!
http://www.buxcomm.com/pdfzips/hum-and-noise-solutions.pdf

 

[xtatik]

http://k0bg.com/noiseid.html
Have a look here for some info on identifying mobile noise problems. It's pretty much all you need to know.

 

[rusty_tlc]

I'd check the alternator ground and OEM noise filter cap* first though. But it really sounds like you need some filtering to me.

*Not sure if your year LC has this, my 84 does.

 

[gary in ohio]

Are you getting the noise through the built in speaker or a remote speaker?
if remote, have do you get the noise through the internal speaker? if so some caps and filters on the remote speaker might help.

re-routing the power cables might help. Also a quick check is to connect the radio to another battery/power source besides the vehicle battery. Now start the vehicle and turn on all your accessories. You still getting the noise? If so then its coming in via the antennas, not the power.

Do you hear the noise when you disconnect the power and turn on your accessories?

The k0gb site mention has lots of checks, just start walking through them. Just keep in mind in a non-stock vehicles, often times its the "performance" parts that cause issues. they often dont test for RF interference issues.

 

[NorCalLC]

Are you getting the noise through the built in speaker or a remote speaker?
if remote, have do you get the noise through the internal speaker? if so some caps and filters on the remote speaker might help.

re-routing the power cables might help. Also a quick check is to connect the radio to another battery/power source besides the vehicle battery. Now start the vehicle and turn on all your accessories. You still getting the noise? If so then its coming in via the antennas, not the power.

Do you hear the noise when you disconnect the power and turn on your accessories?

The k0gb site mention has lots of checks, just start walking through them. Just keep in mind in a non-stock vehicles, often times its the "performance" parts that cause issues. they often dont test for RF interference issues.

Thanks for the feedback guys, I will check into all the ideas asap.

Gary, the noise is coming through the built in speaker (no remote speaker yet) and as of this morning it's only when I turn on the headlights, after other elec items are on. I will try the things you suggested and narrow it all down.

There's no noise when the radio power is off, it's only through the radio with the headlights on, so far anyway.

 

[Tennmogger]

Another consideration is the condition of the battery. Does the noise go away if all the accessories are off?

The alternator is apparently doing it's job because you are able to run all those extras, but, as the battery is loaded down, if it has a weak cell then it can't act as a low impedance filter. As load increases, spikes normally filtered by the battery then come in on the power lead.

Something to try anyway.

Bob WB4ETT