UHF Antenna advice

[DoubleDisco]

Hi,

I am looking at getting a UHF radio and antenna for my '98 Disco 1 V8.

I'm struggling a bit with antenna choice. I don't have bullbar fitted so am wondering the best place to install the antenna? Magnetic mount on the roof, gutter mount, standard OEM spare wheel carrier, bonnet/wing?

What are the advantages/disadvantages of these locations?

I would also like to remove the antenna when not on a trip etc. Should I be looking for a certain type of antenna/connection?

And finally....

Steel or Fibreglass antenna and the reason why.

Thanks for your help,

Cheers

Adam

[pk.hoarder]

Hi Adam,

Roof mount is OK as you can easily remove it - but I did "lose" one of these to a low hanging branch on a heavily wooded track once. No damage but only 'cos I noticed in time.

Spare wheel mount is a long way from the radio and you will have to get the cable from the bodywork into the tailgate I think, not impossible but fiddly. Longer cable = more losses and more chances for damage.

Maybe one of those old school brackets that bolts to the guard and pokes up through the gap between the guard and the bonnet (google bonnet edge mount Z bracket)? My D1s have had huge margins between bonnet and guard so bracket would fit OK.

Roof mount helps range but only in really flat country.

Steel or fibreglass? Depends on what you want to do with the radio. I mostly use UHF to communicate with mates on tracks or sometimes with a handheld if someone is walking ahead or wading a creek or something (back in the day...) - so short range and really a coathanger would work. The longer fibreglass ones can provide higher gain which extends the range. There is a bit of a run-down at http://www.mobileone.com.au/antennas/cb477info.html

Antenna "gain" is not really gain like an amplifier - it is more a focussing of the energy. High gain UHF antennas spread the energy like a flattish donut, almost no power directly above them, which is what you want on a ground comms system.

Hope that helps

Cheers
Paul.

[DoubleDisco]

Hi Paul,

Thanks for the reply and info.

It will 99% be used for convoy and ground work as you described.

I was thinking by mounting the antenna on the spare wheel mount it would be relatively protected and then feed the cable up behind the lights and above the head lining to the overhead map pockets. Didn't consider the loss of signal strength for a long run though.

I'm thinking bonnet edge mount would be ok apart from if I want to remove the antenna to stop the local yobs snapping it off, the bracket would be left sticking out.
For Roof mount I'm not sure on the best way to run the cable to the roof. Don't really want to drill a hole in the roof (it leaks up there enough anyway!!!). I though about running it down down behind the A-Pillar trim, through the bulk head, out under the bonnet somewhere and then back up the outside of the A-pillar? Not sure how to secure it to the outsode of the A-Pillar so it doesn't flap around. Maybe screw some cable clips in and silicone?

Anyone have any thoughts about that?

[Eevo]

gutter mount


gutter mount has the highest location
higher location = best possible line of sight

i have 2 ant but 1 mount, the ant is removable so you can take it off so noone steals it

both ant are flexiable, branches arnt a problem but you can still take it off for bad tracks and use handheld for car-car communication.

1ant is 2.2dB
the other is 6dB

[lokka]

Adam seeing your after something removable id take a look at this MAGNETIC ANTENNA BASE WITH 3DB UHF CB GROUND INDEPENDENT ANTENNA | eBay (http://www.ebay.com.au/itm/MAGNETIC-ANTENNA-BASE-WITH-3DB-UHF-CB-GROUND-INDEPENDENT-ANTENNA-/271185020978?pt=AU_Electronics_Radio_Equipment&hash=item3f23e30832)

Your D2 will have a steel roof so you can sit this up on the roof and run the cable in through the door and along the map shelf to a roof mounted radio and with this you could even have the thing sitting on the dash inside the car and it will work

This guy is a local to me sort of hes in cessnock NSW his name is mike and he is a verry help full bloke not like all the other nuffies who just want to sell you something to make money he can even do you a radio and antenna package (tho i prefer icom) give his shop a call and see what he can do for you 49911392 Killpatrick Comunications cessnock

[DoubleDisco]

Thanks for all the replies and advice.

I ended up with a gutter mount that I can leave attached to the vehicle. The antenna and cable can unscrew from the mount for easy removal. I just feed the cable through the door.

Went out on the weekend and it worked fine so I am pretty pleased with this set up.

Now on to the next project........

Thanks again

Cheers

Adam

[Jason F]

I know you have already bought a gutter type, but for the rest:
For best all round use, I am putting in a centre of roof type. Its going in the front lower portion of the roof. I'm going for the super flexible short ZCG GRN480 kit.
Also, Uniden have radios with all the gimmics and one smaller than a cigarette packet. The roof front console has a removable unused plate with lots of empty space behind, perfect for the radio and a power connection is behind it ready to go. This means that you only need to run the antenna cable in the ceiling and its only about 600mm long (perfect). The rear roof access plate (centre roof light) allows you to reach in and insert the antenna base using a short stick or if you can get a child with thin arms to reach in.

This is the only optimum arrangement I could find which minimises hard work, radio is out of the way, neat and professional looking, easily visible and accessible with no mess and good reception. The only down side I can think of, is that someone can still reach up and pinch the antenna. On the other hand, its so short, they probably would not bother.

The short flexible antenna has a good gain at 4dBi. The idea is that you can still access car parks with low ceilings and not have to worry too much about the antenna. When you need 9dBi for outback use, you just unscrew and fit a high gain antenna.

By the way, in Australia (well at least NSW anyway), the legislation says its illegal to have any antenna mounted in your view from the windscreen (even if its only 10mm thick). So all of the bonnet, bumper or bull bar mounts are illegal. The government will be targeting these in the future (so watch out) and of course, if you get into a bingle and the other party or your insurance company find out, you have had it.