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Chris
06-10-2007, 08:08 PM
Okay, I admit I'm pretty thick when it comes to radio stuff but installing a CB antenna is something that should be easy. Drilled a hole in my rear bumper spare tire swing out. Attached the antenna, ran the cable and attached to the radio. Easy enough.

Thought I'd take advantage of Mr. Cardinal's offer of his SWR meter to tune it. Get pegged reading on all channels. Yeah, I read the manual to find that indicates a bad ground. :confused:

The Wilson antenna has a wire hanging off which I assume is an alternate ground. Ran it to the license plate light ground. No change. WTF?

:hill:

Shark Bait
06-10-2007, 08:41 PM
Pics? I'm very visual. :p:

ScaldedDog
06-10-2007, 09:00 PM
That wire off the Wilson doesn't take the place of a regular ground. My suspicion is that your swing out isn't grounded because the hinge and latch point prevent good metal-to-metal contact with the bumper and frame. Can you test that with multi-meter? If that's the case, connect the frame and swing out with a grounding strap, and things should get better.

If the swing out is grounded, then I bet you grounded the antenna itself, rather than the antenna mount. If the little 3/8" threads are touching metal, that's bad. A multi-meter will tell you that quickly.

Mark

Chris
06-10-2007, 09:10 PM
That wire off the Wilson doesn't take the place of a regular ground.

What's that wire for? :confused:

My suspicion is that your swing out isn't grounded because the hinge and latch point prevent good metal-to-metal contact with the bumper and frame. Can you test that with multi-meter? If that's the case, connect the frame and swing out with a grounding strap, and things should get better.

Mark, Okay now I understand how the hinge would cause this problem. If you can tell me how to test with a multi-meter I can do it. :p:

If the swing out is grounded, then I bet you grounded the antenna itself, rather than the antenna mount. If the little 3/8" threads are touching metal, that's bad. A multi-meter will tell you that quickly.

To prevent the little 3/8 thread from touching metal (they probably are) do I just need a larger hole with the antenna centered and not touching the edges?

:bowdown:

Chris
06-10-2007, 09:11 PM
Pics? I'm very visual. :p:

I'll see if I can get a couple.

Chris
06-10-2007, 10:44 PM
This any help?

Shark Bait
06-10-2007, 10:47 PM
My suspicion is that your swing out isn't grounded because the hinge and latch point prevent good metal-to-metal contact with the bumper and frame. Can you test that with multi-meter? If that's the case, connect the frame and swing out with a grounding strap, and things should get better.

If the swing out is grounded, then I bet you grounded the antenna itself, rather than the antenna mount. If the little 3/8" threads are touching metal, that's bad. A multi-meter will tell you that quickly.


Does this help?

Not really. I guess I would agree with the question about the swing out. And from the picture, you may have grounded the antenna out at the mounting point.

Chris
06-10-2007, 10:54 PM
Not really. I guess I would agree with the question about the swing out. And from the picture, you may have grounded the antenna out at the mounting point.

I'm guessing the mounting point now that I know. I'll see tomorrow.

:cheers:

ScaldedDog
06-10-2007, 11:15 PM
I'm guessing the mounting point now that I know. I'll see tomorrow.

:cheers:

It's hard to tell from the photo, but does the threaded end of the spring touch the mount on top? If so, that's at least a major part of your problem. You should have a little plastic grommet that looks kind of like two stacked washers, one slightly smaller than the other, with a 3/8" hole in the center. That grommet fits in the mount, then the spring threads fit through the hole. that keeps the antenna (the threads and everything above it) from contacting the vehicle. Does that make sense?

Mark

Chris
06-10-2007, 11:46 PM
It's all clear to me now - doh!

The threaded end of the spring probably does touch the mount on top, I used the very small & thin nylon washer provided, nothing resembling a grommet like you describe. I'm sure I can find one, drill my mounting hole bigger to accomodate it and all should be well. Nothing like that needed on the bottom?

So what's that extra wire on the antenna for?

Thanks, I appreciate it!

:cheers:

corsair23
06-10-2007, 11:49 PM
It's hard to tell from the photo, but does the threaded end of the spring touch the mount on top? If so, that's at least a major part of your problem. You should have a little plastic grommet that looks kind of like two stacked washers, one slightly smaller than the other, with a 3/8" hole in the center. That grommet fits in the mount, then the spring threads fit through the hole. that keeps the antenna (the threads and everything above it) from contacting the vehicle.

x2

I'm an antenna noob and even have a no-ground antenna cable from firestik that supposedly doesn't care whether the mount is grounded or not. I still spike the SWR meter readings on mine though and am not sure why :(

However, you should have at least one and sometimes 2 nylon insulator washers (technical term I "borrowed" from Firestiks webpage :hill:) so the antenna itself doesn't ground out (IIRC).

Here are some "borrowed" pics as well showing the insulator washers. My setup looks like the left most mount. I think yours resembles the mount on the far right which looks like it only requires 1 insulator. :thumb:

corsair23
06-11-2007, 12:02 AM
I used the very small & thin nylon washer provided, nothing resembling a grommet like you describe. I'm sure I can find one, drill my mounting hole bigger to accomodate it and all should be well. Nothing like that needed on the bottom?

So what's that extra wire on the antenna for?

No clue about the extra wire (I'm using a Firestik) but I might have an extra nylon insulator washer floating around if you have trouble finding one.

:cheers:

ScaldedDog
06-11-2007, 12:16 AM
It's all clear to me now - doh!

The threaded end of the spring probably does touch the mount on top, I used the very small & thin nylon washer provided, nothing resembling a grommet like you describe. I'm sure I can find one, drill my mounting hole bigger to accomodate it and all should be well. Nothing like that needed on the bottom?

So what's that extra wire on the antenna for?

Thanks, I appreciate it!

:cheers:

Having this conversation is funny to me, as I remember having the exact set of questions and issues you're having.:D

Jeff's pics are great, and you'll need one of those plastic grommets on top, and none on the bottom. The shielding of the antenna wire should be grounded at the antenna base, and it connects to the outside screw mount at the end of the cable. When it touches the mount, like yours does, grounding is accomplished. (NOTE: I'm assuming your spare tire carrier is grounded. If not, you'll continue to have problems.) The center wire of the cable should *not* be grounded, and that's why you need the grommet.

The extra wire on the Wilson Silverload antennas is used to shift the impedance (IIRC, the chances of which are not good) to get a better SWR *in some situations*. The general idea is to tune it as good as you can without the wire. If your SWR's are poor (>2.0 but less than infinity) after you're sure you've got everything right, then you can ground the extra wire. If it helps, great. If not, disconnect it and tape it to the antenna. (I've tuned two of these, and it didn't help either time. YMMV.)

BTW, did you roll your own connector on the end of the wire? If so, test the wire to make sure the center doesn't have continuity with the shielding. It' very easy to let a copper strand from the braided shield touch the center pin.

Mark

Chris
06-11-2007, 12:48 AM
x2

I'm an antenna noob and even have a no-ground antenna cable from firestik that supposedly doesn't care whether the mount is grounded or not. I still spike the SWR meter readings on mine though and am not sure why :(

However, you should have at least one and sometimes 2 nylon insulator washers (technical term I "borrowed" from Firestiks webpage :hill:) so the antenna itself doesn't ground out (IIRC).

Here are some "borrowed" pics as well showing the insulator washers. My setup looks like the left most mount. I think yours resembles the mount on the far right which looks like it only requires 1 insulator. :thumb:

Thanks for the pics, I'll pick one up tomorrow. :thumb:

Chris
06-11-2007, 12:53 AM
Having this conversation is funny to me, as I remember having the exact set of questions and issues you're having.:D

Jeff's pics are great, and you'll need one of those plastic grommets on top, and none on the bottom. The shielding of the antenna wire should be grounded at the antenna base, and it connects to the outside screw mount at the end of the cable. When it touches the mount, like yours does, grounding is accomplished. (NOTE: I'm assuming your spare tire carrier is grounded. If not, you'll continue to have problems.) The center wire of the cable should *not* be grounded, and that's why you need the grommet.

The extra wire on the Wilson Silverload antennas is used to shift the impedance (IIRC, the chances of which are not good) to get a better SWR *in some situations*. The general idea is to tune it as good as you can without the wire. If your SWR's are poor (>2.0 but less than infinity) after you're sure you've got everything right, then you can ground the extra wire. If it helps, great. If not, disconnect it and tape it to the antenna. (I've tuned two of these, and it didn't help either time. YMMV.)

BTW, did you roll your own connector on the end of the wire? If so, test the wire to make sure the center doesn't have continuity with the shielding. It' very easy to let a copper strand from the braided shield touch the center pin.

Mark

Nope, bought the wire complete with ends, I know enough not to go there. :p:

Just when I think I'm understanding this you throw in "shift the impedance" :D

By this time tomorrow I'll know whether or not I need to ground the bumper or go back to my little magnetic antenna. :rolleyes:

Chris
06-11-2007, 03:19 PM
Thanks Mark for your guidance and Jeff for the pics. Got what I needed at Ace and everything's good. The swing arm hinge isn't a great ground but the latch is fine. Get readings from 1 on the low channels creeping towards 2 on the highest. The adjustment on the end doesn't help at all so it's all good now, readings I can certainly live with. ;)

Once again, asking a few questions save hours of frustration!


:beer: :beer: :beer:

corsair23
06-11-2007, 04:42 PM
Good deal! Wish mine was working as well as yours :(

Someday I'll get it working right :hill:

Chris
06-11-2007, 05:29 PM
I wish I could help you but it sounds like an impedence issue.

That was it in my case, my ignorance was impeding me.

:D

ScaldedDog
06-11-2007, 11:35 PM
I wish I could help you but it sounds like an impedence issue.

That was it in my case, my ignorance was impeding me.

:D

So *that's* what that extra wire is for!!!

Glad it worked out.

Mark

Rezarf
06-12-2007, 04:12 PM
Chris-

To get any good reception out of the setup on the swing out, you will need to add a grounding strap... not just a wire. Honestly, I am not absolutley sure why but in my search from guys in the know it, it is what you have to do to get a proper ground.

It is the big fat flat ground strap found on some cars between the engine and the frame. Most NAPA's carry them.

Then once you have one. You mount it to the swing out carrier right beside the hinge and attach the other end to your cruiser, maybe through the bumper bolts or something similar.

It isn't hard just a bit of work.

Hope it helps.

Drew

Chris
06-12-2007, 06:46 PM
Chris-

To get any good reception out of the setup on the swing out, you will need to add a grounding strap... not just a wire. Honestly, I am not absolutley sure why but in my search from guys in the know it, it is what you have to do to get a proper ground.

It is the big fat flat ground strap found on some cars between the engine and the frame. Most NAPA's carry them.

Then once you have one. You mount it to the swing out carrier right beside the hinge and attach the other end to your cruiser, maybe through the bumper bolts or something similar.

It isn't hard just a bit of work.

Hope it helps.

Drew

Thanks Drew, I'll keep it mind but since my SWR readings appear good I hope it will work as it is. I won't really know til I use though. :)