Can I shorten my UHF CB Aerial?

No.

Changing the length of the antenna will have a significant effect on it's performance and in the very worst case may cause damage to your radio.

Mike Harding

Zebu, you buy a shorter one which may be tuned with a coil in it or change the position or both. The higher the placement the better even a half wave which is also tuned length.

Can't you adjust the garage door?

Just but a shorter one, you can get them under 3', it will be fine for town and short trips. Then put the longer one on for outback trips

Thanks fro teh feedback - the aerail is actually only 60cm long to begin with - I need to take 15cm off. Can you get them that short?

Currently it is mounted on the top bar of the bull bar. What if I drop it down onto the base of teh bullbar. It may touch the top bar of the bull bar - will taht have a negative effect?

to be honest i never use it, and if I do its just to talk to a car in front or behind.

thoughts

Dropping the mounting position may end up shielding the antenna with the body of the vehicle and that will affect the range of the radio.
Is it causing any damage to the door or is it just irritating? If the tip catches on the way in and out it shouldn't hurt the antenna as they are quite flexable.

Simple rule.
Put the UHF antenna up as high and in the clear as you possibly can. Anything else will be a compromise.
How much of a compromise is variable. If you want it low on the front bullbar, mounted at the bumper level... expect your VSWR to rise and performance to drop, especially to the rear of the vehicle.
I had a guy come in with a UHF and antenna he had installed. He complained that it wasn't working very well. The antenna was mounted on the tow bar tounge, the entire length was alongside metalwork. When I said it needed to be raised, the remarked that it would then hit his carport roof!
Sometimes you need to make compromises, in his case... the performace of his radio had to suffer because of the carport roof. Some people work the other way and modify the cars home to suit the additions. Or, unscrew the antenna when not in use and put up with a little inconvenience.
But NEVER, EVER cut an antenna just to make it fit !!

Can't you just raise the Garage?
(sorry) I tried not to..........:-0

Reiner

Why not take it off? Takes a whole 10 seconds

My question is what sort of vehicle are you running and how loooooooooooooow is your garage? I've got a 3ft aerial on the top mount of the bullbar on my GU and I've gotta say I'd lose the cabin roof of the patrol before I'd have to worry about the aerial!

A quarter-wave whip works quite adequately -at UHF that's 15cm (6 inches).

Use that as your everyday antenna and only put on a big antenna when you need maximum range.

How easily you swap antennas depends on your current antenna. For a 1/4 wave antenna, there is no earth connection needed to the whip.

Mike

I have an autotune on mine with a 1.5m whip on it (1.x mm stainless).

It hits my door & roof, and the doors at the ambulance station but it's not more than an annoyance.

Go the 15cm whip if it's really bothering you. (That's about a quarter wave length for 476MHz which is approximately UHF frequency - can't remember exactly but google will tell.)

Performance will be slightly affected but over convoy distances you won't notice.

Keep the other in the back for a spare.

Dave