Alan Gomes
Sustaining Partner
I have had two sources of EMI/RFI on my boat that I just discovered recently. These had been affecting the reception on my VHF for years, I suppose. The reason it had not been obvious to me is that the VHF radio seemed to receive just fine. But what was happening is that the EMI was either clobbering the weaker signals so as to put them below the squelch threshold to where I didn't hear them at all, or in other cases it weakened the signals that came through, but which I simply assumed were just weak signals. It was affecting both my VHF handheld as well as the fixed-mount GX2200 unit.
I discovered the problem the same way in both cases: I just happened to switch off or remove the offending source right at the moment an affected signal happened to be coming over the VHF, and the difference became evident.
The first source, which I discovered last December, was my three MR-16 LED cabin lights. Not long after I got the boat in 2012, I replaced the lights over the table, galley, and by the quarterberth with MR-16s. These were off-the-shelf MR-16s from a non-marine source. Being 8+ years ago, I think the technology has advanced considerably, though perhaps I could have found "quiet" LED has I thought to look at the time. Anyway, I went to marinebeam.com and bought three of these babies. That seemed to take care of the problem, because switching them on and off made no difference as to any noise or effect on any signal, even weaker ones.
The other source, which I discovered while at Catalina last week, was coming from the two-port USB charger that plugs into the cigarette light plug, which I use to charge my cell phone, Kindle, and so forth. It looks like this:
Here again, I just happened to switch off the power to my cigarette lighter plug and a weak station that was below the squelch suddenly appeared! So I was able to replicate the problem over and over by switching on and off the receptacle in the presence of just such signals. I have just purchased, but have not yet installed, this as a replacement. This is specifically a marine unit. According to the specs, this is supposed to be filtered "for reduced electronic intereference." My hope is that it is significantly reduced. I'll report back how it works after I've installed it.
It's amazing that I never observed the issue before, but I guess I never happened to switch this stuff of or on right when the VHF was doing something that would make me observe it. For signals that are loud enough I would not notice any difference.
Anyway, just a word to the wise. If you are using LED light or cigarette light chargers on your boat, you might want to look into this just to be sure.
I discovered the problem the same way in both cases: I just happened to switch off or remove the offending source right at the moment an affected signal happened to be coming over the VHF, and the difference became evident.
The first source, which I discovered last December, was my three MR-16 LED cabin lights. Not long after I got the boat in 2012, I replaced the lights over the table, galley, and by the quarterberth with MR-16s. These were off-the-shelf MR-16s from a non-marine source. Being 8+ years ago, I think the technology has advanced considerably, though perhaps I could have found "quiet" LED has I thought to look at the time. Anyway, I went to marinebeam.com and bought three of these babies. That seemed to take care of the problem, because switching them on and off made no difference as to any noise or effect on any signal, even weaker ones.
The other source, which I discovered while at Catalina last week, was coming from the two-port USB charger that plugs into the cigarette light plug, which I use to charge my cell phone, Kindle, and so forth. It looks like this:
Here again, I just happened to switch off the power to my cigarette lighter plug and a weak station that was below the squelch suddenly appeared! So I was able to replicate the problem over and over by switching on and off the receptacle in the presence of just such signals. I have just purchased, but have not yet installed, this as a replacement. This is specifically a marine unit. According to the specs, this is supposed to be filtered "for reduced electronic intereference." My hope is that it is significantly reduced. I'll report back how it works after I've installed it.
It's amazing that I never observed the issue before, but I guess I never happened to switch this stuff of or on right when the VHF was doing something that would make me observe it. For signals that are loud enough I would not notice any difference.
Anyway, just a word to the wise. If you are using LED light or cigarette light chargers on your boat, you might want to look into this just to be sure.
