UHF radio transmit causing anchor light to turn on

[maldotcom2]

Hi guys,

The title pretty much says it all. I've just installed my UHF radio, and when I hold the transmit button, the anchor light turns on. Also the switch on the dash for the anchor light illuminates (on).

I seem to be getting pretty poor signal on CB frequencies, haven't tried the marine frequencies.

[Yarraone]

If this radio is in your boat it should be a VHF? but as to the problem that has a big issue with a short or a cross wire somewhere for sure.. one thing you could do is to disconnect your anchor light from its power source which should be at the anchor light switch.. Then hit the transmit button and see what happens.. this would tell you if it is a cross wire or direct short as the only power source then would be from the radio, as the anchor switch is off. Also the cross of wires or short would be between the anchor switch and the light, because the switch is dissconected.. So it should be easy to trace.

[maldotcom2]

The radio is just a run of the mill GME 27 meg marine radio.

Could it possibly be because I'm powering the radio from my main switch panel, which controls all the lights. Would I be better to run a dedicated power cable from the radio to the battery?

Edited March 3, 2012 by maldotcom2

[rockfisherman]

If its a 27mhz radio it's not UHF.

There's definetly some sort of bridgeing occurring where youve made your connection Judging by the story you've told. I think you might have stripped to much sheathing off your wires, check both conductors, as it could also be a backfeed.

[Fisherman36]

Funny how it powers other things up only on transmit. It will be drawing more power on transmit than if it's just sitting there receiving, so the normal occurrence is for other electronics to possibly dim, not power up when you transmit, but this really shouldn't happen anyway if everything is correct. When you transmit, it will pump power to the antenna. You haven't done anything with the antenna wire by any chance have you? All you should need to do with that is mount the base and run the coax to the back of the radio. No separate power leads should run to the antenna, and nothing else should be anywhere near, or have a chance of touching either the base of the antenna or the coax (antenna lead) or plug where it goes into the back of the radio.

[mako2000]

Clean up all the EARTH wires, all the way back to the Battery.

[helliconia]

Funny how it powers other things up only on transmit. It will be drawing more power on transmit than if it's just sitting there receiving, so the normal occurrence is for other electronics to possibly dim, not power up when you transmit, but this really shouldn't happen anyway if everything is correct. When you transmit, it will pump power to the antenna. You haven't done anything with the antenna wire by any chance have you? All you should need to do with that is mount the base and run the coax to the back of the radio. No separate power leads should run to the antenna, and nothing else should be anywhere near, or have a chance of touching either the base of the antenna or the coax (antenna lead) or plug where it goes into the back of the radio.

It will also draw more current in transmit, which could bridge any close gaps that aren't bridged in low current use.

Check the wiring behind the switches and along the of the power leads for the radio. I wouldn't think the antenna would be shorting to turn a light on but can't hurt to check that too. Try disconnecting the aerial lead and hit transmit and see if the problem still occurs. If not, its in your power cabling somewhere.

I always use heatshrink when I strip wires to terminate them, adds some extra insulation down to the point I want exposed.

[maldotcom2]

Ok it's taken a while for me to get a result with this. It is intermittent whether the anchor light is affected. However I went out on the bay today and called for a radio check on 88, all clear. So the equipment is working correctly. I've also noticed heavy static through the radio when cranking the engine, it's some sort of feedback issue, all the wiring is new, soldered and heat shrinked. Maybe I should put a diode somewhere?

[Fisherman36]

Interference is common with the 27mhz radios. Mine gets it when I use the tilt/trim. You could try one of those ferrite noise surpresses that they use on cars (looks like a donut that you wrap the power cord through a few times). They sometimes use them to get rid of ignition noise. Most auto electrical places sell them but it's hit and miss whether it would get rid of it all or not. I haven't bothered on mine but let me know if you try it and whether it works or not.

Cheers