Hello all, I just installed an ICOM M422 and when it is powered on, after the initial beep, it goes on standby, and I can hear a low level hissing sound, fairly quiet but audible all the same. I have the co-axial hooked up to it, a remote microphone in the cockpit (cable not wireless!!) and the red and black wires and that is it. The remote station in the cockpit also makes the same low level but audible noise. I uncoupled the coax and the noise remained. I unplugged the remote mic form the back of the unit and still the noise was there. I know when I anchor up and chill that the low level hissing noise is going to drive me nuts. Any pointers? Neil
ICOM VHF Radio Noise
- Thread starter Neil Hodgson
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Bad ground?
You mention the "black and red" wires. There is some AC somewhere on the 12v. Usually there is a filter in the radio that will take that to ground. If it were me I would hook it up to my little tractor battery, nothing else attached. If it still has the hiss then the radio is defective. If the hiss is gone then you will have to troubleshoot the ground or 12v supply.
You mention the "black and red" wires. There is some AC somewhere on the 12v. Usually there is a filter in the radio that will take that to ground. If it were me I would hook it up to my little tractor battery, nothing else attached. If it still has the hiss then the radio is defective. If the hiss is gone then you will have to troubleshoot the ground or 12v supply.
Squelch was set
Don, I set the squelch as per the manual instructions: turn it all the way anticlockwise and then turnot back until the noise disappears.No Joy
. Ed: There is a screw thread that says grd on the lower corner of the frame. If I were to attach a wire to it, where would I be best to ground it out at? I have a 29.5 hunter and I could run a wire from the radio (at midships) and up into the overhead electrical panel mounted on the cabin roof. Thaks to both of you. Neil
Don, I set the squelch as per the manual instructions: turn it all the way anticlockwise and then turnot back until the noise disappears.No Joy
. Ed: There is a screw thread that says grd on the lower corner of the frame. If I were to attach a wire to it, where would I be best to ground it out at? I have a 29.5 hunter and I could run a wire from the radio (at midships) and up into the overhead electrical panel mounted on the cabin roof. Thaks to both of you. NeilTake it out and try it at anchor
every marina I have ever seen has incredible amounts of electromagnetic interference EMI from all kinds of sources. I would take the boat out and anchor with everything else shut off. You can isolate the source of interference by turning things on one at a time. Then you can start checking for proper grounds and filters for various appliances. You can put toroids on the various sources too.
every marina I have ever seen has incredible amounts of electromagnetic interference EMI from all kinds of sources. I would take the boat out and anchor with everything else shut off. You can isolate the source of interference by turning things on one at a time. Then you can start checking for proper grounds and filters for various appliances. You can put toroids on the various sources too.
Here's an easy test
Heres's an easy test, Turn the unit on and unplug the antenna, if the background noise is gone with the antenna unplugged than the noise you received is an RF {radio frequency} and you'll have to solve the noise at the source. If you unplug the antenna and the noise is still there than finding a better ground or a noise filter may help. good luck, Jack PS. NEIL, After rereading your post it looks like you have already tried my suggestion. Trying a filter or a better ground may help. good luck, Jack
Heres's an easy test, Turn the unit on and unplug the antenna, if the background noise is gone with the antenna unplugged than the noise you received is an RF {radio frequency} and you'll have to solve the noise at the source. If you unplug the antenna and the noise is still there than finding a better ground or a noise filter may help. good luck, Jack PS. NEIL, After rereading your post it looks like you have already tried my suggestion. Trying a filter or a better ground may help. good luck, Jack
Solid ground.
"Solid ground" is something we sailors try to avoid. Unless it is for our electronics! The only real ground on a sailboat is the negative battery post. The engine and the negative bus in the electrical panel should be the equivalent of the negative battery post. Try running a simple jumper wire from that case ground to the engine.
"Solid ground" is something we sailors try to avoid. Unless it is for our electronics! The only real ground on a sailboat is the negative battery post. The engine and the negative bus in the electrical panel should be the equivalent of the negative battery post. Try running a simple jumper wire from that case ground to the engine.
Noise test
This is a simple if drawn-out test. Turn everything electrical off and unplug from shore power (don't forget to turn the bilge pump off). If the noise is still there, disconnect the antenna. If the noise is still there, try adjusting the squelch. If the noise is still there, return the set to the dealer. If there is no noise at this point then, one-at-a-time, turn on everything electrical aboard that is connected to the 12 volt batteries listening after each is turned on. If the noise starts when you turn on item X, then X is the noise maker. If nothing makes the noise start, plug in your shore power and see if that makes the noise start. If nothing makes the noise start up again CONGRATULATIONS you have fixed the problem.
This is a simple if drawn-out test. Turn everything electrical off and unplug from shore power (don't forget to turn the bilge pump off). If the noise is still there, disconnect the antenna. If the noise is still there, try adjusting the squelch. If the noise is still there, return the set to the dealer. If there is no noise at this point then, one-at-a-time, turn on everything electrical aboard that is connected to the 12 volt batteries listening after each is turned on. If the noise starts when you turn on item X, then X is the noise maker. If nothing makes the noise start, plug in your shore power and see if that makes the noise start. If nothing makes the noise start up again CONGRATULATIONS you have fixed the problem.
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