Icom- M803 problem on yacht.

[Paul ReadingParticipant]

I have an ocean going yacht fitted with an Icom-M803. I can send and receive transmissions of the 4mhz band and above (HF) but I have huge amounts of background noise on the 2mhz frequencies (MF). I have been unable to find the cause of this problem. Icom have been very helpful but they don’t make house calls.

I am trying to find an highly knowledgeable ham radio enthusiast who likes a challenge who would be prepared to visit my boat in the River hamble and go through the system to see if he can see what is wrong. I have tried everything iCom have suggested and I have completely run out of ideas.

I need someone with a scanner who might be able to confirm if something in the boat is generating noise (I have tried switching off everything I can) or is able to find fault with the installation, we have a proper through hull ground plate.

To give you a clue the coast guard broadcasts MF weather information from Milford Haven, Holyhead, Belfast and Stornaway. When we sailed from Falmouth to the outer Hebrides we were unable to hear the broadcasts. I have just crossed Biscay and we were unable to hear the broadcasts on Coruna and Finistare

[M0PWXParticipant]

first things first

type of antenna and cabling you have?

if the coax is not weatherproofed at the connectors correctly water in the coax can cause havoc

when did this start happening? did you have any new kit / lighting installed just before this happened? (DC-DC convertors / inverters and LED lighting can cause havoc on lower HF bands)

if you can isolate circuits in a breaker box, turn everything off you can, if that improves reception then turn circuits on one at a time to see if you can isolate the culprit

if you have a little portable AM radio, wander round the yacht and move the radio near equipment, as anything generating RF interference will show up as increase in noise level on the radio, a bit like sweeping for a spy bug 🙂

if you can find the culprit, then next issue will be resolving the issue, could be as simple as using some ferrite cores on supplies to LED light fittings to replacing the offending item if not cost prohibitive

to eliminate cabling / antenna if you can get a simple mag-mount or whip antenna you can plug directly in the back of the radio and see it it makes any difference

the final thing is the transceiver itself, could it be something silly like the rF gain turned right down? or even a fault on it?

hope this gives you a start and helps

Peter
M0PWX

[Author]

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