CB Aerial Change

[Greynomad]

We have an older CB (presumably about 2003 - same vintage as Girt) with a small aerial mounted high on the drivers side.
The aerial is one of those single-wire types with the coil wound into the centre... about 60cm tall.

Son & Heir has donated to the Parental Unit a longer aerial surplus to his requirements.
It is a vinyl-coated thing about 1.25~1.4m long, with wires visible under the coating snaking up the length of the unit.

When I screw it down in place of my original, I can hear transmissions, but can't transmit.

Before I head off to the nearest CB specialist (Albury? after the Big Move), does anyone have suggestions which don't include disassembly of the radio, or rewiring Girt?

[TassyJim]

The 'new' antenna might be for a different frequency band. That would certainly cause problems.
It also might be for the correct frequency but requires a different base to give the correct impedance match for the radio.

Jim

[Greynomad]

TassyJim,
I think S&H bought his about 5~7 years ago. Has (obviously) a newer CB & bought two aerials: short & long (for town & country use).
He now only uses the short aerial for both. Suspects he was over-sold in the Aerial Department.

If either of your suggestions proves to be the answer, it sounds to me as if a trip to a CB specialist is inevitable.

If the aerial is for a different frequency band, is it of any use, or should I bin it?

An impedance mismatch should be fixable with some extra load in either the aerial mount or the back end of the radio (my guess!); n'est pas?

[BruceS]

If it was used to transmit for quite some time with a badly tuned aerial or none at all (broken wire?), then it may have cooked the transmitter side of it.

[supersparky]

Ray, Do you really need to replace the aerial on Girt? The type that you describe as already fitted is usually sufficient for the CB to operate correctly. A longer aerial will generally have a shorter life span because of overhanging tree branches etc. Unless of course it is mounted lower and then you would lose most of the benefit of it being longer. If it is the correct type for the CB frequencies it may just need an SWR adjustment. If you can wait until next week I will get some more relevant info from the radio techs when they return to work next week.
I am fairly certain that Jims post is 100% correct.

[SteveW]

The better the aerial, the more crap you hear. If the aerial you had was good enough - leave it. No doubt that a better aerial is better if you are into the finer points of radio, however, you probably want to hear what's happening 5 kilometres up the road and talk to someone with eyesight. Beyond that you'll just be driven nuts.

[Greynomad]

Bruce,

When I reinstalled the original aerial, CB transmits OK. So no internal probs with transmission side indicated.

Jim, Steve & Dave,

What you say is true.

The current aerial reaches a fair way, and has performed faultlessly for four years (with me - and probably some years with previous owners).
It's just that I was given at a cost of $0, what appeared to be a better aerial, which would give my CB greater range.

Perhaps I should follow Ron Tauranac's advice to Jack Brabham: "If it ain't broke, don't fix it."

[madiesmum]

your original aerial is for you uhf cb radio.
the aerial you were given sounds very much like an aerial for a 27mg cb radio.
if that is the case then no it wont work for your ufh radio.

[TassyJim]

There are generally two types of antenna base.
One is the bog standard type designed for a 'quarter wave' antenna with a low impedance feed point.
The other common one is for 'ground independent' antennas.
These antennas are good for mounting on fiberglass bodies etc and have a high impedance feed point.

Getting then wrong will be 'disappointing'

Jim

[soccerkiddo3]

Ray

A guess on my part not able to see both yours and your son's setup but the problem is most likely in what the son didn't give you.

Aerials on 4wd these days are normally made up of 3 parts; a spring mount, a short metal tube and a long whip. When they give a second "aerial" it is normally just a longer whip. The short metal tube that I suspect you are missing acts as your ground plane when transmitting. A necessary part for that type of aerial. You could try a CB place to buy the bit but I suspect it will be easier/cheaper to buy a new complete aerial, or you could just use your old one.

Geoff