Mobile Radio Setup

When I purchased the FT-857D, I was looking for a radio that could function well both as a base station and in the car. Initially I only plan to use VHF/UHF in the car (a Ford Fiesta Ghia MK6 Facelift), and the below details my current installation.

I needed to be able to easily move the FT-857D between the car and home, so had to purchase additional power cables and brackets for mounting at both locations. I also wanted a fairly clean & tidy installation, but without having to make too many holes in my new car!

The picture to the left shows a side-on view with the head of the radio mounted on a MountGuys mount that is attached to one of the bolts holding the passenger seat in place. The radio is in easy reach and doesn't get in the way whilst driving. The radio itself is on a custom mount under the passenger seat.

Kit List

Radio Mount:



Radio Power

To minimise any RF leaks/interference between the radio and the car electronics I opted to wire the radio directly to the car battery.

I adapted the power cable that comes with the FT-857D to fit in my mobile installation. I had to splice the cable after cutting to fit through the bulkhead, using some heavy duty ball and socket inline connectors (yellow in the picture).

Standard car battery terminals were then attached to the other end of the cable, and finally all exposed cables were wrapped in plastic cable protectors to provide some extra insulation.

The wiring umbilical cord feeding through the bulk head in the car was very tightly packed, and I wasn't too keen on forcing the radio power cables through with fear of damaging the car wiring.

Instead I opted to peal back the black circular rubber seal and feed the cables around the edge as shown in the picture on the left. This turned out much easier than expected, although there is very limited access from under the bonnet to where the wires emerge.

The picture above shows the view with the glove compartment removed, showing the run for the power cables and also how I mounted the external speaker (bottom right). Luckily there were some mounts for the centre console that I reused to fasten the bracket for the external speaker.

The final step was to connect up the power cables to the battery. This fitted quite neatly over the battery, held in place with some zip ties. I finished off by wrapping all the wire up to the bulk head with plastic cable protector, so nothing was exposed under the bonnet.

Radio Installation

To hold the face of the radio I opted for a mount from MountGuys. This easily attached to one of the bolts holding down the passenger seat and provided a solid fixing. The holes on the FT-857D remote mounting kit lined up exactly with the mount, so this was easily attached with no modifications.

I decided to mount the radio under the passenger seat after looking at the cable runs required for different locations. Rather than have to hide four cables from the front to the back of the car (power, speaker, mic, control), it seemed better to just run the single antenna coax from the back.

The cable for the microphone runs along the rails for the driver seat to the front, with the female to female microphone connector that comes with the YSK-857 kit. This allows the microphone to be easily disconnected, and also nicely keeps the cable out of the way when driving.

To hold the radio, I covered a small piece of wood in external speaker cloth/cover and screwed on the FT-857D mobile mounting bracket. This sits nicely under the passenger seat and doesn't slip around due to the cloth under the wood against the car carpet.

This also makes it easy to slide out when I need to swap the radio over, as you can just slide the front seat forward and access it from the rear passenger door.


The antenna is a Diamond NR-770RSP dual bander, which offers 3dB gain at 144MHz and 5.5dB at 430MHz. It is spring loaded at the base, and just under 1m long.

The mount is a Diamond K-400 heavy duty hatch and boot lid mount, which I've attached to the bottom of the Fiesta boot, on the right hand side to avoid getting hit by branches.

The antenna has a fairly low profile over the top of the car, so easily fits into multi-storey car parks etc. Time will tell how much this affects performance.

It's fed by a Watson W-ECH mobile aerial cable kit, which is 5m of RG-58. To keep the cable run tidy I use some self adhesive cable mounts down the boot hatch - as can be seen in the picture on the right, to the left of the lights.

The feeder then runs under the boot carpet and rear seats, down to the passenger seat where it attaches to the radio.

m1bwt/mobile.txt · Last modified: 2012/09/25 08:46 by simon
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