VHF / Mobile Phone Aerial

[rrees]

I am looking for a combined VHF / Mobile Phone Aerial to put at the top of the mast
To do this I was looking to use the exsisting co-axial cable and use some sort of combiner / splitter unit at the mast head / by the chart table.
I will be installing a Nokia car kit with the co-axial aerial input option
Does anyone know of any good suppliers and advice on carring out the task

Thanks

Richard

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[MainlySteam]

Look at http://www.banten.com/m20011.htm for example. Just does the 900MHz band however.

I have never used their antennas so cannot make any comment on performance. However, because of the large loss on coaxial cable at cellular phone frequencies I have never bothered doing anything other than just mounting a regular car antenna on a hatch as close to the phone site as possible (we have to use an external antenna as our boat is metal). It is certainly much cheaper.

John

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[charles_reed]

Sounds fine in theory - but the cellphone signal is so minute that most of it will be lost on its way up the mast.

That means you'll need to boost the signal.

Also the length of aerial on vhf needs to be tuned to the working frequency - fortunately the single band phones (900) are fairly close to the marine frequencies, but I doubt you'll ever get it to work effectively with either of the other two cellular frequencies.

Some time ago an Italian firm was offering a kit which actually used the vhf set to boost the cellular signal - don't know how it worked and I'm not sure even if it was tri-band.

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[robp]

<<fortunately the single band phones (900) are fairly close to the marine frequencies,>>

Don't think so, are they? 900MHZ (UHF) as against 156MHz - 162+MHz (VHF). Can't see any gain (no pun...) in a mast top cell phone aerial.


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[poggy]

Hi,

I wouldn't bother with a cellular aerial at the top of the mast, I can't see it adding a lot to the range of the phone.

In the old analogue days the car phones had a 25W output which was a lot higher than the hand helds, but the car kits now are passive as far as signal strength is concerned. Mostly cars have phone aerials because of the metal structure of the bodywork, this isn't such a big problem on GRP boats. If you want an aerial use a stub aerial on the coach roof where it won't be stood on.

I am no expert but I have had a few car kits and different phones. I have a telematics system in my current car and it has a tiny aerial on the roof.

Poggy


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[extravert]

You are unlikely to increase your range. GSM mobile signals are limited to a 30km maximum even if you do have line of sight over a greater range.

Any signal booster would have to be type approved, which is very expensive, which is probably why you don't see any.

<hr width=100% size=1>One day, I hope to own a real boat.