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Old 10-14-2009, 06:20 AM
FireRanger FireRanger is offline
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Dual antennas is called co-phasing. What it does is increase your gain along the lengthwise axis of the truck. So you get a boost in transmit and receive gain in front and behind you. It does not enhance or inhibit off the sides.

Truckers use of it is not because of the trailer but because that ahead and behind them is where they want and need that gain in signal. They're talking to people on the highway, not people somewhere else in la-la-land. So that boost is useful to them.

In order for co-phasing to work properly, you need a specific distance horizonallly between the antennas. Its been awhile but I believe this is about 8ft (1/4 wavelength). This works quite nicely on 18-wheelers because the cabs are HUGE and they can attain that spacing. This is not a happenin' thing on a Ford Ranger. You are getting maybe 1/2 the required spacing and it will not work properly. It looks cool but it is not effective.

The most effective place for a single antenna is smack in the middle of the roof or smack in the middle of a metal cap over the bed. This gives a big even ground plane. Unfortunately since CB antennas have to be so big (usually at least 3ft), rooftop mounts are often not practical. They either look dumb or won't let you fit in a garage. The most popular spot is the back of the cab. Your ground plane and radiation pattern will be uneven and not optimal, but for most of our uses, it is perfectly sufficient. Talking locally to other users within a few miles is typically what most people here do and it works fine.

As far as your 3ft vs 4ft question, it comes down to looks and practicality. It may not fit in a garage at 4ft.
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