

| Subject: | Re: CB antennas |
| Date: | Tue, 21 Jan 1997 17:01:20 +0200 |
>> Just to have a last word on the antennas. The glass mount CB antenna that >> Sean intalled will not get out "forward and to the right" as he said. >> Location of the antenna is not influenced by the vehicles body unless is >> uses the body as a "ground plane". And that means that the antenna must be >> attached to the metal of the body. I agree on this. >> The glass mount doesn't need a ground plane, so therefore the reception >> will be omni directional, and the body of the van will BLOCK the signal >> going to the front and left. Glass mounted SW antennas mostly have resonant coax cables. Don't cut them to your needs. This is to match the 50 Ohm output of your transceiver. Every antenna mounted on cars have preferred directions. But blocking a signal on CB waves is not possible on cars. Even hand helds are working inside, of cause with a high loss of field strength. The glass mounted are working on the same principle as the antennas for fibre glass boats. > Sorry to disagree but the wave length of a 1/2 wave CB antenna is 18 > feet. The body is 9 feet The body is not in resonance with the wave. The body should reflect the antenna in that way you get a virtual dipole which is resonant with the wave length. But a car is a little bit small for an 36 feet wave and it will be a compromise. The body presents a capacitor against earth and this will change by moving the car. > and the antenna is 9 feet making a total of > 18 feet. This is called a 1/4 wave antenna. Anything smaller has > what is called a base Not only base loaded but also top or midsection loaded .... > load, (a coil), that simulates a 9 foot antenna. > Therefor placement of any CB antenna is very important! Helmut '80 Camper
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