GME aerial on Navman vhf radio?

[Jackinthebox]

Just bought a Navman 7000 VHF the other day & picked up a GME VHF aerial by accident. Funny thing is, the plug fits the radio and there's plenty of length in the cable..

I went back and got the "right" aerial for it which is by Pacific aerials and bloody typical, the cord on this one isn't long enough as I have now got a 469 open tiller steer and have mounted the radio down the back where i sit.


Does anyone know if you can use the GME aerial with the Navman radio? (both aerials are probably exactly the same & made in the same components factory)

Cheers,
Mick

[finga]

Re: GME aerial on Navman vhf radio?

Should all be dunky dorry matey

[Jackinthebox]

Re: GME aerial on Navman vhf radio?

Thanks Finga,

anything else I can check on the cable itself? It's just coaxial cable isn't it?

The Pacific aerial cable has the code RG - 58C/U on it.

Mick.

[finga]

Re: GME aerial on Navman vhf radio?

The cable specs should be the same on the two but there are a lot of different types of coax with different specs.
I know the cheap GME 27meg radios need the corresponding GME aerial but the VHF units should be able to be interchanged between the different brands.

[FrankFWM]

Re: GME aerial on Navman vhf radio?

Hi Finga,

Why do GME 27meg radios need GME Arials?

[finga]

Re: GME aerial on Navman vhf radio?

I was told something about loading (ie resistance or capacitance) or something like that.
That was the reason they (GME) were giving me when my old 27 meg wasn't working right as it had a different aerial.
I reckon that's a load of bollocks to have to save a few components in the radio.
That's why I went to VHF instead

[Simmo2]

Re: GME aerial on Navman vhf radio?

A full wave on 27 meg is about 11 mtrs in length.
A full wave on VHF is about 2 mtrs in length.
Therefore, the two antennas need to be correctly matched to the correct radio. ie a 27 meg 11 mtr antenna will not work correctly on a vhf radio. It will present a mismatch to the output of the radio, and 'bounce back' most of the power to the radio, not out into the air. Being that most VHF's are around 25 watts, the power amplifier in the radio will heat up and more than likely die with extended transmissions.
The only thing you would have to do in buying an antenna, of what ever brand, is to make sure that somewhere on it or its blurb, it says 1) it corresponds to your radio (HF or VHF) and 2) it says marine.
A HF marine antenna is tuned around the 28 meg section of HF, and a VHF antenna is tuned around the 156 meg section of VHF.
The coax, being rg58 just means that it is 50 ohm coax, not like rg59 (which is 75 ohm and used for TV arials)
If Cable is too long, really it should be cut and reterminated to the right length.
If too short, then an extension can be made up. (if it is too long, tryt not to coil it up, tie with cable ties, and hide!! Try to lay the extra out in lengths somewhere. Tight coils in an antenna system change its properties also!
Hopoe this helps!

[Jackinthebox]

Re: GME aerial on Navman vhf radio?

Thanks Finga & Simmo2,

looks like i'll be getting the GME aerial then if it has the same coax code on it.

Cheers,
Mick.