uhf cb @ antenna

[bob10]

G,day, just purchased G.M.E. TX3220 RADIO and ZCG Scalar antenna, model ZN3-77-10, [ground independant.] I'M very much like Sgt. Shultz on this, intend installing radio on the dash[centre], antenna on bullbar, good choice, or is there a better alternative? look forward in eager anticipation to any replies, Cheers, Bob10:twobeers:

[waynep]

Sounds OK - but about putting it in centre of dash do you mean on the top ? - You don't say what type of car you drive.

[slug_burner]

Yes the antenna if ground independent will be suitable for bullbar mounting, or anywhere else for that matter. Height is might when it comes to UHF so if you have somewhere else that you can get it up higher you will be marginally better off. Not worth the effort of getting another clamp if the bullbar has a bracket built in.

[bob10]

I drive a Disco2, and I'm thinking about making a bracket for the top of the dash , above the am/fm radio. Would there be an advantage in putting the aerial as close to the edge of the bullbar as possible, to give better reception from behind? Look forward to your advice, cheers, Bob10

[miky]

Would there be an advantage in putting the aerial as close to the edge of the bullbar as possible, to give better reception from behind? Look forward to your advice, cheers, Bob10


As has been said many times before, it is usually a compromise wherever you put the antenna.

The "best" place is in the centre of your roof - on the roof rack or bar or drill a hole in the middle of the roof :o

Most people who have a roof rack or bar would put it on drivers side of the rack to keep it from hitting branches all the time.

Again, in practice the bull bar will work OK most of the time.



.

[OldGreyGuy]

As has been said many times before, it is usually a compromise wherever you put the antenna.

The "best" place is in the centre of your roof - on the roof rack or bar or drill a hole in the middle of the roof :o

Most people who have a roof rack or bar would put it on drivers side of the rack to keep it from hitting branches all the time.

Again, in practice the bull bar will work OK most of the time.
.
On my road car I have a roof rack mounted shorty antenna on the drivers side and this was chosen specifically to stop it hitting branches, etc.

Bullbar should be fine for most antennas as long as they are not too short as height is might.

If all you are doing though is talking to other folks nearby, for example, travelling in convoy and never get more than 1000 metres apart then almost any antenna will do. I know that my half-phase short antenna on the roof regularly picks up and transmits to the local repeater 20-30 kilometres away.

[Mellow Yellow]

There's a lot of useful information on antenna mounting on this site.
www.mobileone.com.au (http://www.mobileone.com.au)

They're also an Australian manufacturer and very good to deal with.

[Bushwanderer]

SNIP
The "best" place is in the centre of your roof - on the roof rack or bar or drill a hole in the middle of the roof :o
SNIP


.
Hi Miky,
I take issue with this comment. With ground-dependent antennae this was the case. Fortunately now, with ground-INdependent antennae, height is might, but placement is not.

HTH,
Peter

[slug_burner]

Hi Miky,
I take issue with this comment. With ground-dependent antennae this was the case. Fortunately now, with ground-INdependent antennae, height is might, but placement is not.

HTH,
Peter

You still get benefit from a reflector, which the roof is. A reflector can give you another 3db of gain.

With monopoles you need a ground just to get the antenna to radiate as designed. The ground independent antennas are usually a dipole i.e., centre fed wip.

[Bushwanderer]

Hi slug_burner,
While I don't question your statement, do you have a source for me to educate myself?

TIA,
Peter

[slug_burner]

I will look around for a suitable article or do some notes to explain.

[Bushwanderer]

Hi slug_burner,
That would be great. :BigThumb:

What I really need is details on why a ground-independent antenna still benefits (by 3dB) on there being a ground-plane.

Thanks Again,
Peter

[Utemad]

If having a ground plane increases your antenna's db rating by 3 db is that really a good thing?
If you want a 4.5db antenna and find it is actually replicating a 7.5db antenna that would be a bad thing in hilly terrain.

[waynep]

All my radio theory ( albeit a long time ago now ) said it is the design of the radiating element ( ie the whip part ) that largely determines the gain. I can see however that perhaps having a flat sheet of metal extending from the ground independent antenna may alter the radiation pattern from a more ( which is really all the a gained antenna is doing anyway. )