UHF Antenna set-ups

To my knowledge there is no advantage to usuing two antennas. You would be better off just using the 9db. If you really wanted extra range you can get directional antennas that use one aerial followed by one or more reflectors. This is of no use to a 4wd. They call them yaggis (not sure on spelling)
My advice is to mount the antenna as high as possible.

Jim.
A small antenna mounted on the roof or at the back over the spare wheel is best on any vehicle, the advantages of high gain antennas is much overstated. The limiting factor on CB range is the signal to noise ratio, a high gain antenna does not help that but placing the antenna as far as possible away from the vehicles electrics does. The reason you can not use 2 Antennas is the impedance maching problem and the signal from the 2 antennas would not be in phase and therefore would cancell out in some directions. To get an idea of the correct set up look at an ambulance or fire truck, these are installed by profesionals who could end up in court if the radio fails. Eric.

You can use as many antennas as you wish Jim but there's really nothing to be gained in your situation. Radio Amateurs stack directional antennas both vertically and horizontal for added gain, some of the moon bounce arrays are huge.

jimmy
no expert but if u want two aerials why not run the coaxials of each through firewall to unit and if in desert connect the aerial most suited and if in high country connnect that one.
obviously u have done a bit of research into aerials suitable for different areas.
for me i use one most suitable to high country etc but at end of day dfor me doesnt really matter as most of time other vehicles in group are within range.
only time there was slight issue was on trip to and from simpson where cars were spread out ie couls have been 20-30km between front and back car of seven cars.
all u do is relay messages if its that important
hope i got drift of your question

Jimmy,
I have a splitter you can have if you like. It's a 3 way unit (Dick Smith from memory). Very simple 3 way switch and has 4 connectors; 1 on one side and 3 on the other. You can run 3 antennas into it and switch to any one of them just by moving the switch knob.
I used to have 3 UHF antennas on my b/bar. What an idiot, eh? I now don't have any on the b/bar, just one up on the roof rack.
Let me know if you'd like the splitter box......it's about the size of a cigarette packet.

Jim, I have a 1m UHF whip mounted on a spring base on the bullbar of my Patrol. It works fine but after some trials I will soon be moving it to the rear, mounted off the spare wheel carrier, alongside a HF whip. Should work fine providing I don't transmit on both at the same time so I'm told. A simple bracket is all that is required, making sure it doesn't stick out to far so that it smacks the body when you open the "spare tyre" door and also clears the wiper arm. When I tested it at the back I found that I had stronger RX & TX than at the front. As well as all this, it is in my vision at the front (front right corner) and it drives me nuts.
I was recently on the Strez and didn't need my radio other than for some idle chatter. It worked great. In my opinion you should set it up to work best for when you are in remote areas, as best as you can with UHF anyway. How often will you use it around town?

Good luck
Lou

Jimmy,

I have recently installed the Icom IC400PRO in my Prado. I went with an antenna mount on a roof bar above the B pillar with the cable running down the side of the windscreen/ A pillar, into the bonnet and down to the firewall then thru and into the centre console bin between the front seats where the radio is mounted. (out of sight from thieving eyes!)

The antenna mount teminates in a screw fitting (BNC i think) that will take any standard antenna. I have two antennas. One is a $14 rubber duckie type about 6 inches long. It is a 3db antenna that is very flexible and is good when I am in woody hilly country. The other is a 6db 1 metre steel whip with the spiral centre section that cost about $65. This is good when in flat open country.

Both antennas are stored in the vehicle and it is literally a 20 second job to pull up and screw on the antenna appropriate to the terrain. You could also have a 9db model if you really wanted.

I have just one wire to worry about with no switch boxes and stuffing around. One risk with having the antenna up high is wiping it off in the scrub on low hanging branches (or low carparks!) but for me the benefit of the better transmission from the higher location makes it worth it. Amazing how many people manage to wipe out a bullbar mounted antenna anyway! You just have to be careful and the other advantage of the screw on connection is you can just hop out and remove it (if you remember!).

When i am around the metro area I genarally have the UHF off and the antenna unscrewed. Less chance of someone souveneering it (or just damaging it if it is not a screw off type) and the language and crap makes the radio virtually unuseable anyway.

Regarding the hi-top roof, if you mount the antenna on the guard or bullbar you are going to lose much of your rearward signal anyway. I would do as suggested earlier and maybe go with a gutter mount that gets up to roofline at least.

Have fun. Hope you find the solution that suits you.

BTW, I am very happy with the Icom so far.

Muddy 'doe