more ground needed?

[bigredmachine]

so i finnaly got the cb installed and it works. i have good short range, used it last weekend wheelin, but not much in the way of long range (under 1 mi). i checked the swr with teh meter and accrost the board its between 2.5-3.0, too high for me. i tryed tuning it with the tip and thats about as good as it got. the set up is a 3' wilson fiber-flex on a firestik k-4 stud with 9' firering cable. its mounted on the endcap of the bumper with a ground strap run to the ground next to the battry where the wiring harness groungs and the antenna grounded to the bunper. the ground from the stud is a 12 or 14 guage wire i cut to make as short as possible. do i need to run another ground to get a better reading? im new to the cb thing so i dont know too much, any help would be much appreciated.

 

[alia176]

see if you have good continuity from the ground point on the body to the fire ring connector. The literature that came with the firering should show this procedure. I didn't see which bumper it is mounted on. If it's rear, then 3' is not tall enough as it needs to extend past the roof line by a foot or more. If it's on the front bumper, 3' should be adequate. My favorite mount is the one that mounts right next to the edge of the hood, on the lip of the fender (passenger side, close to the AM/FM radio antenna). I use firering for this mount.

 

[Bogo]

I'm no antenna expert, but ground when they talk about antennas is different than electrical ground. Yes there is some commonality, but it is to provide a strong ground plane for the antenna to allow the antenna to reference the transmit signal against. It is better to tie the antenna ground to the vehicle sheet metal. Tieing it only to the battery doesn't work.

As for height, the antenna needs to extend above the metal bodywork. In reality the effective length of the antenna is only what is above the body of the vehicle. The metal portions of the body of the vehicle absorbs most of the signal that is transmitted blow it's highest point.

For my CB I use a 4' Wilson magnetic mount with bottom load coil that I stick on the center of the roof. I get around 5 miles from a hand held CB. If I went to a hard mount I'd get a spring and mount the antenna in close to the same spot.

 

[bigredmachine]

it is mounted on the front bumper so the top 2/3 should have enough open air to transmit out. i chose the front end cap so i could keep an eye on how bad its geting beat up and be able to run something a little shorter 3ft in teh front vs. 5ft in the rear. i ran another ground strap from the mount and its better but not really great. its not directly grounded to the battery but the body grounds for the wiring harness near the battery. it may just need a better mount since it is not mounded directly on sheat metal for the body.

 

[Bogo]

What is that bumper end cap made out of? If plastic, then run a ground strap directly from the antenna base to the metal of the bumper. The strap should be as short as possible but allow for motion.

Ground straps for the antennas need to be as short as possible, and as well connected as possible. So if a bumper is not well grounded to the chassis, it needs to be grounded to the chassis at all it's attachment points. BTW: Rust can interfere with a good ground path.

ALso check out Wilson's FAQ: Frequently Asked Questions | Wilson Antennas

 

[alia176]

Ground strap for radio is not a piece of wire! It's a "strap" that is commonly use for actual grounding application, found in most auto parts store with eyelets at each end.

 

[Bogo]

You can use a heavy gauge wire if you want. It just needs to make good solid very low ohm and inductance electrical contact between the parts.

 

[sl33p3]

FWIW "ground" or "bonding" strap can have dual purposes, the only one i haven't heard added, but eluded to is RF grounding. that works best with the braided strap you see. (RF travels on the surface and lots of strands gives lots of surface, DC ground needs cross section). so for antennas you want both, to minimize noise and max efficiency. now "ground plane" for antennas, well there isn't a post char limit that could cover the nuances of that but there are some great discussions here, and i learned a lot at this website.

K0BG.COM

and for bonding/grounding... Bonding

good luck.

 

[bigredmachine]

well after some reading on K0BG.COM an almost educated guess is that i dont need more ground but a better ground plane. i was using a ground wire not a strap. the end cap isnt up to it so its time for a new location. alia176 you said you liked the fender mount, something like this FireStik Stainless Steel Hood/Trunk Mount - Tall - ss174 if your using it how do you like it and is it someithing you would recommend?