Swapping fm antenna with VHF antenna??????

[Any_Weather]

Gday guys, just a quick question about antennas? 18 months ago I had a boat built and have a am/fm radio and also an Icom VHF installed. When I picked the boat up from the fitout. I asked the question of which antenna base is from which unit and the response was "I think this is this and that is that". Now both bass are the GME bases that accept any GME antenna that screws in. The question I am asking is, could I have them around the wrong way and still have them operate? The reason I ask is I have a very limited range on my VHF, as in 20km max and usually a lot less. I tried to swap them at sea last week after thinking this maybe the issue but the VHF one was seized and I couldn't get it undone. I am back home now and broke it getting it out but have replaced it now. On my last boat I could get the rocky met weather report in Fitzroy lagoon with a GME gx600 unit but now I am lucky to get round hill outside the river.
I can try swapping them now on land but just wanted opinions as to whether this could be my issue. Also, the hi/lo button on the mic, what should I be running this on?

Cheers
Lee

[scottar]

If you can use a multimeter it will be a pretty simple task to confirm which base is which. You would normally run the radio on high power.

[Noelm]

GME bases are all the same, just the screw on antenna is different, and the adapter on the cable at the radio end, determine which antenna is which and do NOT swap them around, especially trying to transmit! I think the antennas have a coloured dot on them to tell them apart? Just on the performance side of things, is the new VHF antenna the same length as the old one, and is it mounted as high as possible?

[Noelm]

I just remembered, the GME base has a small clip in bit that has the type on it, as in VHF,FM and so on, you clip these into a spot on the base, and it identifies the base, they are different colours too, and the colour matches the dot on the antenna.

[scottar]

The coloured dot on the base is user fitted so you are only relying on the installer. To confirm it once and for all do a continuity check

[chocolatemoose]

i would of imagined also that the installer popped in the colour chips. green for vhf and yellow for am/fm . if not.....carrier pidgeons are a good alternitive .
lol nar just do as scott said and multimeter those suckers

[Noelm]

I think the dot on the actual antenna is factory done, but the base colour/name is user applied, because all the bases are the same.

[Any_Weather]

Gday guys, thanks for the advice. I disconnected both the end that plugs into the unit on tested for continuity and found they were connected correctly. I was scratching my head still when I was speaking with an electrician mate and I just happen to mention that I had purchased the unit in the US. There was the problem, I had t changed the setting to international. Such a simple fix and I have put up with this poor performance for 18 months. Thanks again for your ideas.

cheers
lee

[scottar]

That won't cause poor range but it will stop the repeater channels from working all together. If you were trying to use repeater channels when out a long way it could be what your drama was.

[Any_Weather]

Yeh we were trying to use 81 and 82 out from 1770. Close boat to boat was fine. I was listening today to both sides of a conversation between Noosa coast guard and a boat offshore on channel 21 which I have never been able to do before. I am located at caloundra.