VHF send issue, buzz sound

[gertonw]

both my VHF radios work fine receiving, but have a loud buzz sound when sending. I even get the same with my handheld. So, I guess something is sending a signal close to the VHF band on my boat. I have tried a lot to no avail.
Any thoughts out there what it could be?

Wes

 

[dlochner]

LED lights? The less expensive bulbs often give or RF noise.

 

[jssailem]

There are a number of possibilities. Perhaps @Ken Cross can help...

1. Antenn connections
2. LED lights
3. Fluorescent lights
4. Motors
5. Chafed antenna wire
6. Antenna issues
7. Poor grounding
8. Chafe on mike wires

Start with the simplistic and then work to th more complex. Turn everything off but the VHF radio on the boat. Test the Radio. If everything is off and the sound still exists, then the issue is in the audio system. If it is clear signal, then it is the other boat systems.

 

[Capt jgw]

Are you at the dock plugged in to shore power, or have an inverter running? Sounds like "AC hum", a 60 Hz (50 Hz in Europe) interference that can show up when AC equipment is running.

 

[gertonw]

Thank you John.
Thing is, I tried already a lot. What baffles me the most is that my handheld radio also sends that buzz tone, at least to the other VHF radios on board.

Wes

 

[gertonw]

Thanks JGW.
According dockmaster it sounds like engine thumping while underway, and while docked to me it sounds like a buzz. No difference if I unplug shore power.
Could it be a short somewhere that might generate this interference/sound?

Wes

 

[jssailem]

Wes try connecting to another boat /VHF radio (even the local Marina base station, use a working channel not the Emergency channel) on your dock in the marina. Use the handheld. That will help to isolate the issue. From what you state it could be RF noise from equipment on the boat.

If the hand held to a friend is positive, then I would start with all the boat systems off and try to communicate. If signal is not clear then you can conclude it is not your boat but another source near your boat. If clear then it is your boat. Start to turn the various systems on one at a time, checking as each system comes on line till you find the offender.

 

[gertonw]

yep, that's what I was trying yesterday, and will do again today. One by one, but no luck so far.

Wes

 

[jssailem]

It is a process. Never easy. If it was easy you’d just turn the offender off when using the radio until you could get it fixed.

Good luck and keep us informed.

 

[Ken Cross]

If you tried with the shore power unplugged, it is likely on the DC system. first try your handheld away from your boat. That will verify it isn't on the radio it's self or a problem with the person listening to you. Try turning everything off on the boat and use your handheld (This includes your inverter if you have one.) Then power up your boat one thing at a time. You should eventually locate the problem when the noise comes back.

Ken

 

[gertonw]

Hi Ken, thank you for your respons.
I'm on it :-| and trying

Wes

 

[Brian D]

I can somewhat understand your boat radio buzzing. But the handheld. Is the handheld connected physically to the DC power of the boat? And, is it doing it on all channels?

 

[gertonw]

Hi Brian, the handheld is not connected. So, the buzz is coming through the airwaves, distorting the sending, on any channel.
Receiving from other boats or land is fine, so must be different frequencies?
Gerton - Wes

 

[Brian D]

Well, if you are hearing it transmitted on all channels, it is a broadband noise, not specific to any frequency. The problem I am having is the lack of detection when in receive mode. Besides electronics on the boat, do you have any other electrons on your person such as any device that will emit an RF frequency? Also, when did you start to notice this phenomenon? Did you detect it or did someone you were talking to tell you that you had a buzz on your signal?

 

[jssailem]

Personal emitted RF energy... Pacemaker?

 

[gertonw]

Harbor master informed me when I was coming in. I changed to handheld and he stated that was better, but not good.

Still running around healthy, no pacemaker.

I am thinking I have a short somewhere, thus should be able to find via elimination, but as it is a 25 year old boat, lots of cut cables that I am removing one by one ...

 

[jssailem]

it is a 25 year old boat, lots of cut cables that I am removing one by one ...

Oh I know that experience. My boat was launched in 1974. Wiring is still (or at least part of it, I am making changes till I can do a total rewire) original. I have elected to do the rewire in phases, until I get to the point that I can do the whole thing. With each phase I try to plan it out as part of the total. For instance, when the original charger failed, I installed a new one and upgraded the wires involved with charging. Also addressed the batteries. When I replaced the Alternator I took the same approach and removed the not in use wiring behind the engine panel, replacing the connectors and upgrading the routing of wires.
What ever you do make a wiring chart. It will be handy as you proceed and will remind you what you have already completed. Check out the wiring info from MaineSail. Marine How To – Boat Repair, Upgrades, How-to's
Very helpful.

 

[gertonw]

Hi John, just replaced all antenna connectors to no avail. But, now my handheld sounds okay, so must be something in the D.C. Circuit somewhere.

 

[jssailem]

It is a start... Sounds like you are on a positive path to success.

 

[Meriachee]

If you turn everything off, everything even the ship vhf, no shore power connected or on, and use the handheld, does it still do it?