My Range Rover 4.0/4.6 CB Installation
Objectives
Choice of CB
Mounting Location
Antenna Mount
Wiring
How it Worked Out

Ron Beckett's Installation

Sources

Objectives
In setting up the CB in my 4.0, I aimed for some improvements based on experience with the earlier installation. The antenna size and location should be optimized for maximum range, and the mount should be rugged enough to withstand the repetitive g-forces of four wheeling. Finally, the transceiver and handset should fit in with the look of the Range Rover's interior and always be ready to hand. 

Choice of Transceiver
While I was researching currently available CBs, Chris Dow's Cobra 75WXST in his Defender 110 caught my attention on a trail ride. Similar in concept to the Uniden used in my Classic, the Cobra has all the controls on the microphone, connected to a small remotely mounted junction box. In the intervening years both microphone and box have been downsized considerably. In a recent internet search (November 2005) I found that these radios can now be obtained from Buy.com for only $97 (search for Cobra CB or see this link to take you straight to this product).

Mounting the Transceiver
 The microphone bracket is mounted on the dash just above the right hand side of the radio (see photo at top right), with the spiral cord running back between the passenger seat and the transmission tunnel. The handset  is readily accessible to both driver and passenger, the display is easily visible and the cord is neither in the way nor prone to tangling. The remote box mounted under the rear of the passenger seat, drawing power from the nearby 12 volt line driving the BeCM.

Antenna Mount
To improve reception and better withstand off-road gyrations, I decided against the through glass mount used on my Classic Range Rover. Optimal reception calls for an antenna planted in the middle of the roof -- but this is problematic for garages and car washes. One solution, which I am adopting initially, is the K40 mount which allows the antenna to be attached and removed via a rugged bayonet fitting to a magnetic mount that I leave permanently in the middle of the roof (see photo at left, looking back over the roof rack).

A drawback of this arrangement is the need to climb out and attach the antenna when it's needed. Ever faithful to the Range Rover philosophy of decadence combined with superior function, I began designing a powered remote controlled mid-roof mount, so the antenna achieves optimum performance but can be raised or lowered at will from a switch inside the vehicle. This would provide the ability to use the CB at any time without having to stop, get out and attach the antenna as was necessary on my Classic. Conversely, I would also like to enter garages, parking buildings and car washes without getting out and removing or restraining it. The plan would be to mount the antenna base to the shaft of a 12 volt reversible gearmotor (about 4 inches long and 2 inches in diameter, with 300 oz in of torque at 6 rpm) attached to a roof rack crossbar. To lower the antenna, the motor would pivot it 90 degrees rearward. This design is just hypothetical at the moment.

Wiring
I decided to wire the CB so it is always powered, rather than tie it to the ignition and/or power seat supply as in my previous Classic installation. The main disadvantage of the latter in actual use was the nuisance of losing the channel setting every time the ignition was switched off. The other approach, however, runs the risk of accidental battery drain through leaving the CB on. I found some convenient terminals for the +12V and ground wires on the side of the BECM under the front left seat (see photos below).

Tapping into the BECM for power: This is a side view of the BECM with the seat trim removed. I used terminal C107 (always on) for the +12V, and terminal C623 for the ground.	Close-up of C107, a convenient terminal at the front of the BECM fuse box -- shown here with the insulating rubber boot removed. (It can be replaced after connecting to the terminal).

At first I was reluctant to mess with the BECM, given its reputation for causing problems, but the "connector" I tapped into (C107 -- actually a screw terminal post) had a nice fat wire coming into it directly from Maxi Fuse 5 (60 amps) in the engine compartment fuse box -- it actually supplies fuses F8, 9, 10, 20 and 28 in the BECM fuse box, each of which is 30 amps, so I figured the small currents drawn by the CB would hardly be noticed. This supply is always on, which suited me perfectly.

Ron Beckett's Installation

Ron Beckett installed a Uniden 476 MHz CB with a detachable head in his 4.6. The photo at right shows Ron's impressive 4.6 dash with a number of custom-installed accessories described belpow, including the CB.

The main body of the CB radio is in the loadspace, and the extension speaker is double-sided taped under the rear of the center console. His installation is shown in the photo at right, with the detachable head of the CB mounted on the console panel above the car radio. The microphone is mounted under the headlight switch.

Also visible in the photo is a double cigarette lighter socket which Ron mounted to the top of his dash using heavy duty automotive double sided tape (not the household type which comes off in the heat).  This is fed via a fusebox under the bonnet (hood). Ron says the trouble with the standard ashtray cigarette lighter is that it is controlled by the ignition key.

The black box with the LEDs just below the auxiliary cigarette lighers contains the power supply for Ron's Garmin eMap GPS (which mounts on the double sided taped-on mount to the left of the black box and below the face vents).  Also contained in the box are LEDs for the dual battery controller (to be fitted) which was also fitted to Ron's previous  RR. (He installed a second battery in the rear in the wheel well under the floor).  The other LEDs monitor the brake pump and the EAS compressor.  When they are switched on, the LEDs are illuminated.

(Aside: To get all these wires through the firewall, Ron ran a length of multi-core trailer wiring into the cab via the grommet behind the cooling system expansion tank. See the page on running cabling through the firewall for illustrated details).

Finally, the photo also shows Ron's cell phone installation.

If you have installed a CB in your 4.0 or 4.6 Range Rover, please email me with your experiences so we can post them here to share with other owners.
 

CB Equipment Sources

I recently discovered (November 2005) that Buy.com   has the all-in-one Cobra 75WXST CB Radio I used in my 4.0/4.6 CB Installation for only $97.99, while most other sources I found in a previous search had it for $139.99 to $181.50. They also have other CBs and accessories at super low prices, including suitable magnetic mount antennas.