Stealth UHF CB Radio Install

This article was first published in 2007.

Over the years CB radio in cars has varied enormously in popularity. Twenty-five years ago it was an urban craze, with cars sporting huge antennas and terms like ‘10-4’ part of the popular lexicon. Then things started to go quiet and there was the change from AM to UHF. Nowadays, unless you’re into serious Outback four-wheel driving or you’re a dedicated mobile radio enthusiast, it’s pretty rare to find CB radio gear in cars.

After all, who wants a big whip antenna (and how are you going to mount it in cars that haven’t for years had gutters?) and where’s the space in a modern car’s cabin to integrate another piece of gear? The days of screwing a radio to the underside of the dash have long disappeared. And anyway, aren’t CB radio frequencies just full of foul-mouthed idiots with the social skills of brain-dead parrots?

Well, let me tell you that while there are plenty of parrots out there, there’s also a huge range of people who every day effectively use UHF CB radio. They’re the people on the road – nope, not so much in the cities but on the highway. Every long distance truck has a CB – and they all use channel 40. Straightaway, anyone listening on that channel will be warned of accidents, road hazards, road works, unusual weather conditions – the lot. Caravanners and motorhomers – especially the now numerous retired ‘grey nomads’ to be found on the nation’s highways – very often have a CB radio and they usually advertise the channel they’re on with a sign on the back of the van that might read: “Bob and Jo, Channel 15” or the like.

On a long journey, a CB radio allows trucks to become your friends – there’s nothing like the improvement in safety that comes from trying to overtake a semi on a two lane country road when you can actually talk to the truck driver about approaching traffic and upcoming bends. In an emergency, a CB radio can be simply invaluable. Over the years I’ve also been warned of many road hazards – one example was when a small mountain of sediment had been washed across the road by a flash flood (at night it was completely invisible). I’ve hitched a ride with a truck driver after a breakdown (again at night – and who would pick up a hitchhiker without first being able to talk to them on the radio?) and I’ve had plenty of conversations that dispelled the boredom of long drives. And that’s not to mention more naughty warnings about the presence of police radars...

So when I bought a car in which I intend to do lots of long drives, one of the first steps was to fit a UHF CB. But (a) it’s a very small car with little spare dashboard space, (b) for aesthetic reasons I didn’t want a big antenna, and (c) I figured it would also be pretty useful to have some extra channels – those of the local police, ambulance and fire brigades. The latter’s fun listening but again it has a serious side: in the bushfire area in which I live, it pays to be able to listen to emergency services.

The radio had to therefore take up only a tiny amount of dash space, not have a particularly visible antenna and incorporate a scanning function that covered additional programmable UHF (but non-CB) channels. Hmmm. Too big an ask? Nope.

Finding Space for the Radio

The radio is one I bought quite a few years ago. It was installed in one car, then when that car was sold, removed ready for installation in the next. But that never happened: the radio simply stayed in a cardboard box. However, such is the quality and effectiveness of the design, it’s still a current model! The radio is a GME Electrophone TX3400. It’s designed and built in Australia.

The beauties of this design are two-fold.

First, the front panel (containing the operation knobs, buttons LCD and microphone cable socket) can be removed from the main body and mounted separately, being joined to the rest of the radio by a 1.8-metre cable. Even with the jam-packed nature of modern dashboards, there’s almost always room for a piece of equipment only 128mm wide x 31mm long x 29mm deep, which is the size of the remote mount head unit. The main body can be mounted anywhere under the dash, within the centre console or even under a seat. It’s also quite small at 128mm wide x 117mm long x 29mm deep.

Second, it’s a damn good radio! Output power is 5W, the unit is fully microprocessor controlled (rather important for reasons we’ll return to in a moment) and has squelch, group and open scan functions (where the scanned channels can be split into two groups), a priority channel and lots of other features that you can read about at www.gme.net.au. Significantly, it has available 10 extra frequencies which can be programmed (more on this in a moment).

The installation was easy – the head unit went to the right of the steering wheel on a part of the dashboard where three small switch blanks were situated. Rather than using the provided bracket, the head unit was stuck into space with double-sided tape – it’s easily light enough to be securely mounted in this way. (But if you do the same, don’t forget to first clean both surfaces with an automotive grease and wax remover.) An opening compartment directly beneath this part of the dash was also big enough to swallow the microphone and its cord. (If you’re going to be listening far more than talking, the microphone can be unplugged and placed in the glove-box. You can then plug it in just before heading off on a trip or when in an emergency you need help.) The main body of the radio was slim enough to be positioned vertically against the inside of one wall of the centre console.

An external speaker (one originally used for an in-car phone) was plugged straight into the speaker extension jack of the radio – this switches off the small (and tinny) internal speaker. The extension speaker was mounted under the dash.

The TX3400 costs about AUD$450. Note that if you have a spare DIN slot available in the dash, a GME DIN fitting kit is available at a cost of about AUD$25.

An alternative radio (but without the remote head unit facility) is the ICOM IC400 Pro which has many more additional channels (60 transmittable and 88 receivable) and has 25 watts transmission power on the commercial transmit channels. It costs about the same as the GME Electrophone unit.

Keeping the Antenna Unobtrusive

Nothing much has changed in mobile antennas – for best reception, drill a hole in the middle of the roof and screw in a big ‘un! But who wants to do that?

These days, nearly invisible glass mount antennas are available that stick to the inside of the front or rear glass, looking rather like abbreviated demisters. These antennas, which have a gain of 2.5 – 4.5dB, are not suitable for cars with metallised film tinting. Costs are in the region of AUD$45 - $75, including cable and plug.

An alternative stealth antenna is an external glass-mount whip. These look much like the antennas that were previously widely used with in-car mobile phones and mount in the same way. They have a gain of 3dB (longer whip) and unity (shorter whip). It’s easy enough to store the longer antenna somewhere in the car (eg under the boot carpet) and have the shorter whip fitted for normal use. When you need the increased range, unscrew the short whip and screw on the long one. The cost for the pair, including the interior and exterior mount and cable, is about AUD$110.

I chose to use the latter approach, locating a unity-gain glass-mount antenna at the top, centre of the windscreen. To prevent wind noise, I enlarged the diameter by slipping some plastic tube over the aerial and then placing heatshrink over the whole antenna.

Programming the Extra Channels

Like many other current radios, the TX3400 is software programmable. Normally this is done by the manufacturer (or an accredited dealer) but you can buy the software and a specific programming cable and do it yourself. The software and the cable total about AUD$100, so if you want to make software changes rarely (or only once, when you program the extra channel frequencies), it makes sense to have the programming done by the vender from whom you purchase the radio (cost for this is about AUD$30).

So what can this software do? In the case of the TX3400, the most important function is the programming of the ten extra channels. But in addition to this, you can disable the functions of various keys, set the squelch levels (the unit has only an on/off button for squelch), calibrate the signal level meter, and set up Selcall and CTCSS modes.

The software for the TX3400 (and many other radios) is available at www.uhfworld.com and I purchased the adaptor cable from www.radioworks.com.au. Note that the software (and cable) require a serial port, which many recent PCs and laptops don’t have.

The ten extra scannable channels can easily be configured to hear local UHF emergency service frequencies such as the SES, ambulance, fire and police. To find the appropriate frequencies, just Google your location and ‘scanner frequencies’.

Conclusion

Shortly after fitting the radio I undertook a contract employment position that required a daily 160 kilometre commute. So each day for four weeks I jumped on the freeway, turned on the car sound system and CB and listened and learned (I didn’t talk once!).

So what did I hear? One night there was a ute on fire, blocking the inner two lanes of the four lane freeway. “Move over to the right two lanes!” said the truckers, giving some two or three kilometres of warning. Another morning the freeway was completely blocked: “Take the Logan Motorway if heading north,” advised the truckies. Most days came the “North-bound slooowwwwwing dooowwwwnnn!” warning as the lead trucks advised their following compatriots that the two lanes of traffic were coming to an abrupt halt, traffic gridlocked on the Gateway Motorway.

In short, tucked behind a big truck in my little car, I was far safer and better informed than I would have been without the radio. And without a huge antenna and piece of equipment stuck on the dash, no-one even knew!

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