UHF Aerials

Best thing for you is to look at the GME web site and get a good,correct handle on why you should choose which aerial and just as importantly where to mount it.

A GME 1018K ???? 6db would be good

Gme aerials are not made zcg any more I believe made off shore

quality could be doubtful

Regards

Oldpop

"so I'd like to maximise the range and signal without paying a fortune."
WHY do you want to maximise the range?
What is the radio for?
The last thing we want is to have to listen to every jerk within 30km.
We use little 1/2 wave antennaes that give very clear reception over varied terrain for around 10km. That is plenty.
If you want emergency transmission, a UHF is not the way to get it.

Cheers,
Peter.
OKA196 Motorhome.

Mount the antenna on the roof if you want the best of both worlds.
Gives you the best range, and you can easily change to a short rubber stubbie for around town and overgrown tracks. The range of the rubber stubbie is pretty good - at least half that of the best setup.
I use the rubber stubbie 95% of the time, and slip on a 6Db when I need the range.

I use one like this, a Mobile One RF470B , 6.5db , $90.00 only . and works a treat.
Raised feed with stainless steel co-linear antenna top & 4.5m coax
This antenna can be mounted almost anywhere and with any type of mount and does not need to be earthed.
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Wayne,

Best to mount in the centre of the roof if possible (usually not possible because of roof rack) as the extra height helps and the metal roof acts as a reflector to effectively increase the size of the aerial. Some cheap aerials require this, other ("ground plane independent") types don't, but will also benefit.
Maximising range and signal - Vehicle mounted UHF CB radios are limited by law to 5watts output. The only control you have over range and radiated power is the gain of the aerial.

The gain of the aerial determines its radiation pattern. Low gain (4.5 dB) radiate pretty much in all directions, including straight up. High gain (9 dB) radiate predominantly horizontally. Intermediate 6 dB types are a pretty good compromise between wasting power by sending it out into space, while not being too tightly confined to the horizontal. Radiating horizontally is fine in flat country, but can limit range in hilly country when the vehicles may be pointing up or down, and the terrain may absorb too much of the more concentrated radiation pattern.

I use a GME 6/9 dB and antenna and can't pick the difference in range between 6 and 9 dB. The 9dB is bigger and more prone to vibration damage, so I usually stick to the 6 dB.

Range - very dependent on terrain, but I expect to get at least 5 km when travelling, maybe 10 km or more if both transmitter and receiver are elevated, and under freak conditions maybe out to the horizon. We find this quite adequate. (If you need serious range, you need hf radio, not uhf.)

Apart from range and cost, an important factor is robustness. The simplest cheapest 4.5 dB UHF aerials score well here.

For general use, I'd recommend a 6 dB aerial, simpler the better. Check out the GME website.

HTH

John

Thanks for the responses from everybody this has given me something to work on

Cheers