Ground radial for mirror-mount CB antenna on semi truck?

[mmckenna]

Which would still be fine, correct?

Yes, just needs to be electrically conductive.

 

[corneileous]

Yes, just needs to be electrically conductive.

So if I didn’t go with a magnet mount antenna on the roof, would something like this actually be better and worth buying over what I have now?

Firestik FG2648B 2 No Ground Plane CB Antenna Kit - BLACK

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[prcguy]

So if I didn’t go with a magnet mount antenna on the roof, would something like this actually be better and worth buying over what I have now?

Firestik FG2648B 2 No Ground Plane CB Antenna Kit - BLACK

Check out this Firestik FG2648B at www.WalcottRadio.com

www.walcottradio.com

Your current setup would work better and a 1.6:1 match is fine for what it is. If you want to improve it get a short 3/8-24 mount CB whip, drill a hole in your mirror mount and put the new whip on upside down and grounded to the mount using a 3/8-24 nut and lock washer. You will have to retune and I would start with the new whip maybe adding an alligator clip or placing your hand near it to see what happens to determine if it needs to be lengthened or shortened then trim if needed. Then do the same to the original whip until the match is as low as you can get it.

 

[merlin]

The mirrors on my Freighliner were stainless, so effectively, the truck was a good counterpoise.
Ham antenna on the left mirror, CB on the right, and tuned up very nicely.

 

[mmckenna]

I'd agree, 1.6:1 ain't bad.
And the dipole setup seems to be a good setup for some trucks.

If you are concerned about performance, there's stuff you can do, like getting rid of the extra coaxial cable you must have coiled up somewhere in the cab?

 

[corneileous]

Your current setup would work better and a 1.6:1 match is fine for what it is. If you want to improve it get a short 3/8-24 mount CB whip, drill a hole in your mirror mount and put the new whip on upside down and grounded to the mount using a 3/8-24 nut and lock washer. You will have to retune and I would start with the new whip maybe adding an alligator clip or placing your hand near it to see what happens to determine if it needs to be lengthened or shortened then trim if needed. Then do the same to the original whip until the match is as low as you can get it.

I have no idea what you’re talking about here…lol.

 

[corneileous]

I'd agree, 1.6:1 ain't bad.
And the dipole setup seems to be a good setup for some trucks.

If you are concerned about performance, there's stuff you can do, like getting rid of the extra coaxial cable you must have coiled up somewhere in the cab?

It’s not necessarily coiled up it’s looped very loosely so that it doesn’t create a choke but OK, I’m glad you bring this up because I was always told that you wanted to use an 18 foot coax whether you need that much or not and I’ve even seen on the back of antenna packages that recommend using an 18 foot coax also.

 

[mmckenna]

It’s not necessarily coiled up it’s looped very loosely so that it doesn’t create a choke but OK, I’m glad you bring this up because I was always told that you wanted to use an 18 foot coax whether you need that much or not and I’ve even seen on the back of antenna packages that recommend using an 18 foot coax also.

The correct length of coax to have between your radio and your antenna is whatever length you need to get there.
What 18 feet does on CB frequencies is hide high SWR from the radio. It doesn't fix anything.
What it does do is make a poorly tuned antenna look good to an SWR meter. Hiding high SWR from the radio might look good on the meter, but it doesn't mean your antenna is working well. Your 1.6:1 SWR may or may not be accurate if you are measuring it at the radio with 18 feet of coax between it and the antenna.

The excess coax adds some amount of loss. Probably not much at 27MHz, but it's not zero. If you don't need it, remove it.