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-   -   Proper mag mount setup (http://www.risingsun4x4club.org/forum2/showthread.php?t=17523)

azcromntic 03-19-2012 06:12 PM

Proper mag mount setup
I purchased a mag mount and an antenna. I have a CB and mic, SWR meter and the proper coax cable for install and doing SWR. How do I set this thing up? I tried to set it up and calibrate it and all but it doesn't seem like anyone can hear me.

The antenna has a black wire coming out of it. I know the antenna screws into the magnetic base but what do I do with the black wire?

I hope to be able to move the antenna inside the vehicle while I am away from the vehicle and then put it back outside when I am driving. I hope the black wire doesn't have to be screwed into the body for that reason.

I just wanted something to reach out if I am on broken down on the road or out hunting and want help. Yeah yeah, cell phone. I broke my cell while hunting turkey so that doesn't always work.

Should I trade it in for GMRS?
Should I sell it and go for HAM?

DaveInDenver 03-19-2012 07:06 PM

Yes on both questions. :-)

With a CB it might be working just fine, just that there's no one listening.

A photo would help, sometimes an antenna will have a wire to let you DC ground it.

azcromntic 03-20-2012 04:01 PM

1 Attachment(s)
Here is a picture I pulled off of the internet of the antenna. No, mine is not seperated or broken like in the picture. :-) Mine is a wilson 3 foot antenna. It bends and all that jaz. Could it be used for HAM or GMRS?

DaveInDenver 03-20-2012 04:17 PM

That's a Wilson, right? Yup, that wire is supposed to be used to ground the antenna.

I've never cut open one of them to see what the heck it might do but I'm also not sure what they're designed to be. I'd have assumed they would be electrically 1/4 wavelength but I suppose if they're 1/2 or 5/8 then the wire is part of the matching network.

I'd tape it to keep it from shorting to anything and try mounting and tuning without it to see what you get. If it will not tune up, try grounding it to see if it helps.

azcromntic 03-20-2012 04:55 PM

That's EXACTLY what I thought, until just a few minutes ago. I did a little research and found a FAQ at wilson website: http://www.wilsonantenna.com/faq.php

It says:

Wilson's exclusive impedance matching transformer is connected through the external wire at the bottom of the FGT and Flex series of antennas. It is NOT a ground wire to increase the ground of the antenna, although using the lead does make the antenna DC ground. It is used when you are not able to get below a 2.0:1 SWR even after tuning. This generally indicates a mismatch of impedance between the coax and the antenna. This can be caused by poor ground but is generally attributed to the mounting location. It re-inserts 25 ohms impedance at the antenna feed point and brings the system back to the 50 ohms required. It is not a tunable device, therefore it is not fooling the radio into thinking the system is matched. It is actually matching the antenna and feed point to the required 50 ohms impedance for the coaxial cable. The most often time it will be used is when the antenna is mounted on the top of tool box in the bed of a pick-up, or on the passenger side of a tractor using co-phased antennas.

You have the choice of either cutting it off or taping it out of the way. In making your choice, consider if you may move the antenna to another vehicle, that installation might require the lead. For the most versatile use of the lead, simply lay it alongside the fiberglass and tape it in place. Using electrical tape will offer the easiest method and offer the best protection against weathering conditions.

I might be using the wrong cable too. The FAQ says:

If you are using less than 1000 watts, and a single antenna, use an 18' length of RG-58/AU. This cable is 95% shielded, stranded center, with 50 ohms impedance. If your power is less than 2000 watts, then change to the RG-8X type (also called Mini-8 or Super 8). For co-phased antennas with less than 1000 watts, use RG-59/AU. For power less than 2000 watts, use RG-11/AU. Both co-phasing cables should be 18' in length on each side. Wilson has available a high quality line of coax cable, and may be viewed at: Coaxial Cable.

Using the recommended length of 18' of coax cable can sometimes result in an excess amount of cable in the cab. This excess cable should be stuffed underneath the dash, under the carpet, or use some other means of hiding it. It should NOT be coiled into a neat roll or coil. This creates an RF Choke and de-tunes the antenna system, in some cases to the point of not being able to get the SWR down to an acceptable level.

And, use of the 3' whip for HAM

I some things to try now at least. How much does it take to get started in HAM?

SteveH 01-04-2017 06:02 PM

Rather than creating a new thread, I have new a Beofeng UV-5R hand held and want to get a magnetic roof mount antenna for it. There are many roof-mount antennas from $7-$30 (or much more) - such as this:


or this: http://www.ebay.com/itm/TRAM-1185-Am...0AAOSwa~BYOPSe

Is there any decent way to determine which one to buy? Not a big financial outlay, but I'd rather not have a spare, junky antenna lying around after I find what I really need.


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