CB gurus please help

chondamx · 03-01-2007, 10:44 PM

Ok, In the last week or so I've been working on my CB install when I've had time and I just finished it up yesterday. Once I got everything hooked up and mounted i had 0 reception. I can't pick up anything. I can get a few weather channels if i hold onto the antenna (obviously me standing outside the jeep with volume on CB cranked), but other then that, nada. Because of this it lead me to believe it might be a grounding issue so i took all the paint off the body were the mount mounts and I scotch brighted the galvanized mount it's self. After all of that it didn't make any change at all.I have checked, checked again, rechecked, and checked once more to make sure all of my connections are tight, and believe me, they are. I made a custom mount behind the driver's tailight and am using a 4ft fiberglass deisel antenna and a deisel coaxle...so what gives? I have this CB if it makes a difference. http://www.walcottcb.com/uniden-pc68-ltw-cb-radio-weather-p-926.html
Thanks for any and all help

-Chris

olds442 · 03-01-2007, 10:48 PM

i know theres a certain way you connect the cable to the antenna mount and if its wrong in any way you wont get anything, thats pretty much all i know about them haha good luck

XJHERO · 03-01-2007, 10:49 PM

you have to tune the antenna with an SWR meter. radio shack has them cheap. or walcott has them too. by the way... you should never hold the antenna with your bare hands while keying the mic. it can burn you.

:edit: you may be able to find some more answers from the guys in the Electrical, Audio, & 2-Way Radio forum on here

madrabbitt · 03-01-2007, 10:50 PM

on a 4 watt radio, its unlikely, but possible.
i've treated a guy who was working on a 10 watt ham rig and got a minor electrical burn from an antenna that wasnt grounded.

madrabbitt · 03-01-2007, 10:51 PM

oh, original reason i came into this thread. theres a electrical section down the page with some really good knowlagable people on this sorta stuff.
i learn from them, and i'm a damn tech.

XJHERO · 03-01-2007, 10:52 PM

i guess as long as you arent holding the tip of the antenna, its not likely... but just lookin out.

madrabbitt · 03-01-2007, 10:56 PM

on a fiberglass wound antenna, if you touch the copper windings if the outside plastic comes off, its also possible... but unlikely.
Of course, the one time you dont think it'll happen... lol

chondamx · 03-01-2007, 10:56 PM

I was just holding the spring at the bottom, not the tip

Anyways, I should still be able to pick something up without having my antenna tuned. I have several friends with very similar setups and without tuned antennas they can still pull a pretty good signal.

XJHERO · 03-01-2007, 10:59 PM

its hit or miss. I have a 4 ft. firefly and it wouldnt pickup anything but WX. bought an SWR meter and tuned it and it works. my room-mate got a second hand CB with a 12" magnet antenna, with no tuning, he picked me up from like 2 miles away. i would suggest at least try to tune it. it couldnt hurt.

madrabbitt · 03-01-2007, 11:01 PM

i've gotten better results from throwing a $10 walmart center loaded antenna on the roof then from my 4 foot fiberglass wilson before it was tuned.

now that i've got that big 66 incher, with a peaked cb, and a tuned antenna, i'm getting 12+ miles easy.

chondamx · 03-01-2007, 11:15 PM

Thanks for the help guys, looks like I'm gonna pick an SWR meter up tomorow.

**EricsXJ** · 03-01-2007, 11:25 PM

I might get some of the terminology wrong but here it goes.

On the antenna mount, there should be a plastic washer between the mount and the antenna and the jeep. One side of the mount needs to be grounded, but the other side (with the washer) should not be, hense the reason for the plastic.

So thats what I'd check first. But either way its good to get a SWR meter and tune the antenna.

**Jerry Bransford** · 03-01-2007, 11:40 PM

Quote:

Originally Posted by XJHERO

you have to tune the antenna with an SWR meter.

He can't hear anything which is not going to be affected by a high SWR in the least. You tune an antenna for minimum SWR so the transmitter transmits with as much power as possible but even a totally untuned CB antenna will still pick up signals just fine.

In his case, he can tune it all day but it won't help because it's 100% apparent there is something wrong with how the antenna mount was installed. When you can't receive at all, it's for sure not that the antenna is simply mistuned.

Chondamx, I suspect your antenna is shorted directly to ground through its mount. The most common cause of this is not having used the small nylon insulating washer required to electrically isolate the whip antenna from its mount. The nylon washer centers the antenna in the mounting hole and prevents it from touching the mount which is grounded to the body. Obviously if the antenna is touching the mount which is bolted to the Jeep, the antenna has a dead-short to ground (the Jeep).

Disassemble the mount and reassemble it carefully making sure to follow the directions and to insure the nylon washer is properly installed and not cracked or broken which will allow the antenna to short to ground.

A good way to quickly know if the antenna is shorted to ground is to turn the CB on then unscrew the antenna from the mount. If you suddenly start getting hiss/noise from the speaker with the RF gain all the way up, the Squelch adjusted so the speaker produces a hiss, plus the volume is up a tad, then that confirms the antenna was shorted to ground. Unscrewing the antenna for this test removes the path the short uses to get to electrical ground so the antenna cable's center conductor can then act as an antenna and pick up signals in the absence of the antenna itself.

Once the antenna mount problem is resolved and you can receive signals, THEN you can adjust the antenna's length for minimum SWR as indicated by nearly any inexpensive SWR meter like can be purchased from some place like Radio Shack.

madrabbitt · 03-01-2007, 11:41 PM

Quote:

Originally Posted by EricsXJ

I might get some of the terminology wrong but here it goes.

On the antenna mount, there should be a plastic washer between the mount and the antenna and the jeep. One side of the mount needs to be grounded, but the other side (with the washer) should not be, hense the reason for the plastic.

So thats what I'd check first. But either way its good to get a SWR meter and tune the antenna.

your lack of the word "thang" does not amuse me

**EricsXJ** · 03-01-2007, 11:56 PM

What I was trying to say, Jerry B said perfectly.