VHF Radio woes

[captron]

I recently installed a new Standard Horizon Quantum Model GX5500S it is installed at the Nav Station and works fine, I have sense installed the companion Ram Mike at the helm and this problem is only with the Ram Mike and it only happens on channel 16, all other channels are loud and clear.
The problem when transmitting on chanel 16 there is a very loud hummmm to the extent that no other boats can here my transmission, but if I switch to anoter channel it is loud and clear. what the??????????

Thanks much,
captron

 

[Chuckbear]

Well, if you had contacted Standard Horizon tech support you would have an answer to your question by now. This is a new unit you say. Chuck

 

[Bill Roosa]

try ALL the other channels

The frequency of the channels dose not follow the channel number so try all the other channels to see if one or two have a similar problem. The manual will no doubt have the channel frequencies listed. You can use it to determine the channels that are right above and below 16. If that premise holds and you have a couple of channels around 16 that have a similar problem then I'd suspect RF feeding back over the ram mike cable.
If there are ferrite donuts use them also. They prevent RF from traveling down the cables.

 

[Brian D]

Agree with Bill. Might check to see if you have a bad ground in the mic cable. The cable itself might be acting as an antenna when you key the mic. But that should show up on all channel I would think. Check to see if by chance you have something turned on in the radio that emits some kind of data stream or tone (such as CCTTS).

Here is a link to the VHF frequencies.
http://www.navcen.uscg.gov/marcomms/vhf.htm

 

[captron]

Thanks guys, I have enough info from y'all to help me trouble shoot the issue, and gosh Chuck calling Standdard Horizon, well that would be like reading the installation instructions, who dose that???
Seriously, best suggestion I will call there tech support.

Thanks much
captron