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-   -   Antenna Mount (http://www.wranglerforum.com/f282/antenna-mount-240557.html)

DarrenT 05-06-2013 10:13 AM

Antenna Mount
 
I'm trying to figure out the best point at which to mount a CB antenna, obviously mag mount on the roof is not an option. I have a UK/EU Team Me-4 80 channel (EU freq. is same as US) with a 3ft Thunderpole whip and coil.
I'd thought of mounting it to the back door maybe, or even putting the mount on the tub above the Light cluster, but I'm concerned about the elevation (or lack of) of the antenna and achieving the best ground possible. Ideas?
Also, where have you guys run your coax through the tub?

CJChet 05-06-2013 10:48 AM

This one works quite well:

TeraFlex Jeep CB Antenna Bracket

DarrenT 05-06-2013 10:59 AM

That seems like a better Idea than a bumper/rear door mount....
I could make it out of the stuff I have in the garage too. What length whip are you guys using?
I know the 3ft was plenty on top of the Land rover, but my TJ is somewhat shorter, and Mounted just above the light it will barely clear the top of the Jeep.
I want to get an idea for what others are using and build/improve on that for my own rig.
:thumb:

Jerry Bransford 05-06-2013 11:04 AM

As my Jeep grew taller & I moved my CB antenna mount higher (it is currently at tail light height), I went from a 4' to a 3' to my current 2' antenna which works fine for offroading & gets out very well. I've been running that 2' for probably 10 years now & never wished I had a taller antenna, it works fine. :)

Water Dog 05-06-2013 11:06 AM

Quote:

Originally Posted by DarrenT (Post 3724791)
That seems like a better Idea than a bumper/rear door mount....
I could make it out of the stuff I have in the garage too. What length whip are you guys using?
I know the 3ft was plenty on top of the Land rover, but my TJ is somewhat shorter, and Mounted just above the light it will barely clear the top of the Jeep.
I want to get an idea for what others are using and build/improve on that for my own rig.
:thumb:

I'm using a 3' firestick. It just barely clips the garage door as I go in so I don't want to go higher. Gets out plenty good for wheeling.

DarrenT 05-06-2013 11:12 AM

:thumb:

Thanks Guys, I'll knock up a mount tonight and stick with the good ol' thunderpole (what a name).

appreciate the info.

4cylToy 05-06-2013 11:20 AM

I put mine on the OEM spare tire carrier.

DarrenT 05-06-2013 11:24 AM

Quote:

Originally Posted by 4cylToy (Post 3724872)
I put mine on the OEM spare tire carrier.

I don`t think it`d work on mine, as it lives on the garage floor ;)
I like the teraflex mount, very neat, minimal drilling of the tub. The less holes I have to put in the tub the better.

K9HDLR 05-06-2013 11:29 AM

Quote:

Originally Posted by DarrenT (Post 3724887)

I don`t think it`d work on mine, as it lives on the garage floor ;)
I like the teraflex mount, very neat, minimal drilling of the tub. The less holes I have to put in the tub the better.

Teraflex mount works awesome. Gotta go with Jerry on the 2' length though. My 3' still hits the garage door.

DarrenT 05-06-2013 11:41 AM

Quote:

Originally Posted by K9HDLR (Post 3724908)
Teraflex mount works awesome. Gotta go with Jerry on the 2' length though. My 3' still hits the garage door.

I have an older 2 ft whip somewhere, but I`ll test the 3 first. I dont have a drive in garage (yet) so hitting doors is not so much an issue. I also just got a working midland 13-882c for $11 :D
I know they`re older, but I love midland stuff. Used to have the Midland Alan, but I left it in the Landy as the shipping company wouldn`t ship radio gear (which they did inadvertently anyway)....... So I`ve got my old Me-4 hooked up now.

AC0QR 05-08-2013 01:49 PM

I put a 2M whip through the front driver's side fender. The fender and the hood make for a good, uniform ground plane, and I was able to tune it to about 1.3 SWR.

DarrenT 05-08-2013 02:36 PM

Quote:

Originally Posted by AC0QR (Post 3733900)
I put a 2M whip through the front driver's side fender. The fender and the hood make for a good, uniform ground plane, and I was able to tune it to about 1.3 SWR.

I got a nice alu mount for $12 at my local radio shack. I was thinking about the driver side fender, but wasn't sure if that would be affected by the radio antenna. Seeing as your SWR is 1.3, it can't be all that bad.
A 2 meter whip? I have a 3ft whip and base coil thunderpole the trucker HD.

rusty1 05-08-2013 10:22 PM

I have the Teraflex mounted on the drivers side with the coax cable going through the tub behind the tail light. Plenty of room to run it through and no extra drilling.

OpieDP 05-09-2013 04:16 AM

Quote:

Originally Posted by rusty1 (Post 3735840)
I have the Teraflex mounted on the drivers side with the coax cable going through the tub behind the tail light. Plenty of room to run it through and no extra drilling.

Same here. Its very clean and was very easy. I run my coax up the grommet above the driver tail light, then up through my roll bar padding. My cb is on an arizona rocky road mount. From the roll bar I go through the mount to the cb in the middle.

DarrenT 05-09-2013 06:32 AM

So I got the mount installed last night, it's got a good 4 point ground to the tub. Installed a new coax (GDSOB that sh*t is expensive here) and cleaned off my antenna of all the road film and crud it brought from the UK.
SWR channel 1 = 2.3, ch40 = 3.0 !!! I know I can trim the antenna some to even up the SWR deviation, but 2.3!! First key up came in at 1.6 on ch 1, then it seemed to jump for some reason (didnt change anything).
I checked all the connections for shorts, bad grounds, everything seems good. I was hoping for figures in the 1.5-1.8 region..... I thought the tub was supposed to make a good ground plane?? :(

AC0QR 05-09-2013 01:20 PM

SWR will change across freq range. It will be lowest at one freq (call it "center" freq) and increase in either direction away. You could do some trimming/tuning to get the center to be around ch 20. This might be "good enough" !

As for the SWR being overall higher than you expected: the tail light is not a great spot for a whip tuning-wise (though it is convenient & looks good - can't argue with that!).

Ideally you want a uniform ground plane below a whip, and no metal above that plane aside from the antenna itself. Obviously this is not the case here - there's the spare & mount, rollbars, and no metal plane below & behind (just the tub in "front" of the antenna).

DarrenT 05-09-2013 01:48 PM

Freq dead centre is ch 19, which is around 2.2. Yes, I retuned it this afternoon out in the middle of nowhere and SWR on 1 is 1.9 and on 40 it`s 2.5.
Half reasonable I suppose. Now I know the high numbers are pretty much a result of reflective surfaces and lack of ideal ground plane. So I was wondering, for all of those of you which have a tail mounted antenna, what are you using antenna wise, and what SWR are you getting?
As Firestik.com list the SS64 mount (same as what I got) as their recommended mount for tub mounting...... Jeep Installations

See tub mount (#3).

Just wondering as there is some contradictory information right there.....

AC0QR 05-09-2013 01:59 PM

When you measure SWR try to put the meter in-line as close to the *antenna* as possible. Otherwise the reading could be skewed by the type/quality/routing of the coax feed line.

Some people put the meter next to the radio, some put it next to the antenna - trying to compare readings between the two locations could result in more contradictory information!

DarrenT 05-09-2013 02:12 PM

Quote:

Originally Posted by AC0QR (Post 3737836)
When you measure SWR try to put the meter in-line as close to the *antenna* as possible. Otherwise the reading could be skewed by the type/quality/routing of the coax feed line.

Some people put the meter next to the radio, some put it next to the antenna - trying to compare readings between the two locations could result in more contradictory information!

'Tis ;)
I've learnt a lot from the hell of riggin up my Landy (Aluminum body).
I'm thinking maybe the whip just isn't the best tool for the job..... I've mailed firestik, see if those guys come back with suggestions (other than buy a firestik - that will be a surprise :rolleyes:) :D

Patrick H 05-09-2013 03:37 PM

Quote:

Originally Posted by AC0QR (Post 3737836)
When you measure SWR try to put the meter in-line as close to the *antenna* as possible. Otherwise the reading could be skewed by the type/quality/routing of the coax feed line.

Some people put the meter next to the radio, some put it next to the antenna - trying to compare readings between the two locations could result in more contradictory information!

You should hook it up at the radio end. The coax is an active component of the antenna and should be included in you SWR readings/ measurements, because the radio sees the antenna and coax as one.

Jerry Bransford 05-09-2013 04:17 PM

I hate to disagree but the coax doesn't affect the SWR on the type of antenna used on our Jeeps. I had to demonstrate that to a disbeliever years ago. I insert the SWR meter at the antenna end of the coax on my TJ for ease of adjustment and at the transmitter end of my HF ham radio antenna's coax. If anyone ever notices a difference in SWR with varying lengths of coax with the type of antennas we use, you can blame that on having used an inexpensive SWR meter. But even when you see that, the length of the cable still won't affect the length at which the antenna is resonant to the frequency. :)

Patrick H 05-09-2013 04:19 PM

Quote:

Originally Posted by Jerry Bransford (Post 3738203)
I hate to disagree but the coax doesn't affect the SWR on the type of antenna used on our Jeeps. I had to demonstrate that to a disbeliever years ago. I insert the SWR meter at the antenna end of the coax on my TJ for ease of adjustment and at the transmitter end of my HF ham radio antenna's coax. :)

OK, if the coax doesn't affect the SWR, you can still install the meter at the radio end and get accurate results. Yes? ;)

Patrick H 05-09-2013 04:21 PM

So I have to ask....If the meter is installed at the antenna end, how do you key the mic and read the meter/ flip the switch at the same time? Long mic cord?

Jerry Bransford 05-09-2013 04:22 PM

Quote:

Originally Posted by Patrick H (Post 3738212)
OK, if the coax doesn't affect the SWR, you can still install the meter at the radio end and get accurate results. Yes? ;)

Certainly, the SWR meter can be inserted at either end for accurate results. Inserting it at the CB end though just makes it more difficult for the person tuning the antenna to see what is happening to the SWR as he adjusts the antenna length. My mic cord can reach close enough to the back when I don't have a helper to key it. :)

Patrick H 05-09-2013 04:25 PM

Quote:

Originally Posted by Jerry Bransford (Post 3738221)
Certainly, the SWR meter can be inserted at either end for accurate results. Inserting it at the CB end though just makes it more difficult for the person tuning the antenna to see what is happening to the SWR as he adjusts the antenna length. :)

Oh. I adjust the antenna, then check the SWR. Adjust again, check again.

Patrick H 05-09-2013 04:26 PM

Quote:

My mic cord can reach close enough to the back when I don't have a helper to key it.
Ah, there's the "key". Get it? Funny guy here...:)

Let the record show that I was wrong about the coax affecting SWR..;)

Jerry Bransford 05-09-2013 04:27 PM

Quote:

Originally Posted by Patrick H (Post 3738228)
Oh. I adjust the antenna, then check the SWR. Adjust again, check again.

So do I. Inserting the SWR meter into the connection next to the antenna just saves me from walking back & forth between the antenna & the meter.

Patrick H 05-09-2013 04:30 PM

Quote:

Originally Posted by Jerry Bransford (Post 3738238)
So do I. Inserting the SWR meter into the connection next to the antenna just saves me from walking back & forth between the antenna & the meter.

The last time I adjusted the antenna on the Jeep it was about 20 degrees out and windy, so getting back into the warm Jeep to check the SWR was a welcome break...:)

Jerry Bransford 05-09-2013 04:40 PM

Quote:

Originally Posted by Patrick H (Post 3738250)
The last time I adjusted the antenna on the Jeep it was about 20 degrees out and windy...

I hear you & hate it when that happens here in San Diego. :rofl:

DarrenT 05-09-2013 05:44 PM

Quote:

Originally Posted by Jerry Bransford (Post 3738238)
So do I. Inserting the SWR meter into the connection next to the antenna just saves me from walking back & forth between the antenna & the meter.

:thumb:
Got tired of walking back and forth, felt like a bleeding tennis player....
Anyhow, I tested at both points and it's the same. For the price it's probably worth just buying a firestik to try.....


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