Posted by Roger Stewart

There are at least two common approaches to accomplish radio communication with other club members while on a group drive.  Using a standard set of FRS Radios easily obtainable from local electronics outlets at a reasonable price, and a CB (Citizens Band) radio which is the focus of this article.   I have used both approaches and eventually settled on the CB route, with an all-in-one handheld transceiver unit.

If you decide you want radio communications and elect to use a CB, then there are 3 general paths you can follow:

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A. Purchase a hand-held portable CB unit (easiest, cheapest, least functional, and most cumbersome to use while driving due to its’ size and attached antennae)

B. Install a control box unit with extended cord microphone (space restriction in Miata cockpit makes this an engineering challenge to find free space for the control box;  and your operating controls (volume, squelch, channel, etc.) are located separate from the microphone, usually requiring you to take eyes off the road)

C. Install an all-in-one handheld transceiver unit (operating controls, microphone and speaker are located within the handheld transceiver).

Options B and C require external antennae and all options will likely be hard to hear at top-down speed if you rely on the built-in speaker of the unit.

Over the years I have used each of the three CB approaches and for me the all-in-one transceiver unit works best for the Miata, especially if you use a mono earpiece as an external speaker (disabling the built-in speaker).

I chose a COBRA 75 WX ST last year after seeing this unit in use by other local Miata owners.  The Cobra has all controls in the handheld transceiver with a separate ‘connector box’ mounted elsewhere.  The connector box has no operating controls, but does have an input for connecting the antennae coax cable, and outputs for connecting the hand held transceiver cord and an external speaker jack that may be used if you desire (I use it). 

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I installed this CB unit in my 2007 NC as follows:

1. Mounted the connector box to the underside of the driver’s seat.  This allows box to move with the seat when seat is adjusted.  I did not remove the seat to do this but did require a friend’s drill adapter to allow me to drill mounting holes from an angle under the seat (not an easy task)

2. Wired the connector box to the fuse block located near the drivers left foot

3. Installed a simple CB mounting clip on my dashboard where the transceiver rests when on a run or when my external antennae are mounted.  Otherwise I keep the transceiver tucked under the front seat next to the connector box.

4. Ordered and installed a custom CB antenna mounting bracket from Ernie Frankl efrankl@centurytel.net . The mount was $15 plus $3 shipping.  This bolts onto the rear deck using an existing hole and supplied hardware.  Note: this bracket and will not work with PRHT models.  Perhaps using magnetic mount antenna is a workable option for PRHTs.

5. Purchased a quality 3 foot adjustable CB antenna (Firestick, I think) and about 20 feet of coax cable ($20-$30).

6. Connected the antennae coax cable to the bottom on the mounting bracket and then routed the coax into the trunk, through the trunk partition behind the drivers seat, into the cockpit behind the drivers seat (most difficult part), and then under the drivers seat for connection to the connector box.

7. Screwed the antenna into the mounting bracket and then got a friend with a SWR meter to tune the antennae height for optimum performance.

8. Once you confirm proper CB unit operation, then purchase a mono earpiece ($4), and 12-15 feet of earpiece extension line cord ($8) and plug the extension line into the external speaker jack in the connector box under the seat. 

9. I routed my earpiece extension line from the connector box under the seat, up the rear of the driver’s seat to behind my ‘right’ shoulder and then secured the female end of the line with a safety pin attached to the seat back.  I then plug the 3 foot ear plug line in behind my right shoulder for use in my ‘left’ ear.  This allows me to avoid the seat belt retractor mechanism and keeps my right rear available for passenger chit-chat or the car’s radio/CDs.   

Posted 10-15-2009