PDA

View Full Version : Swr help



Powerman
04-18-2018, 08:55 PM
I’m installing a cb on my Atv but no matter what I do my swr is crazy high! what should I do?

BOOTY MONSTER
04-19-2018, 08:00 PM
the ATV isn't big enough to be a proper ground plane/ground element .......
just a guess , try a no GP mobile antenna ? im interested in other/better suggestions also .

sonoma
04-20-2018, 01:15 AM
I put one on a 4 wheeler years ago and used a 102 inch steel whip with a 6 inch spring. it worked well for me back then.
make sure your coax is not shorted. you say the swr is crazy high, bad coax can cause this also. a no ground antenna would work the best but make sure you check your setup 1st. no need to buy an antenna when you could have a shorted coax.

Powerman
04-24-2018, 01:46 PM
How to check for a shorted coax?

sonoma
04-24-2018, 03:00 PM
unhook the coax and check it with a ohm meter to see if the ground is shorted to the center pin. make sure you have the antenna mounted properly so the main antenna is not shorted to ground. the plastic spacer goes on top to keep the antenna from shorting to ground. the only part of the antenna that should be grounded is the bottom section. make sure the bottom portion is grounded good to the fram. you may have to scrape paint off the bottom potion where the stud goes through. it needs a good ground for that portion.

Powerman
04-24-2018, 03:28 PM
I went do that no different
Coax isn’t shorted

sonoma
04-24-2018, 04:32 PM
did you make sure the antenna is making a good ground on the lower portion? and make sure the upper portion of the antenna is not making a ground connection. you would be surprised how many people put the plastic washer in the wrong location and it causes a direct short of the antenna.

Powerman
04-24-2018, 05:23 PM
Yes I did that’s all good

sonoma
04-24-2018, 11:22 PM
can you take a picture of the mount? it needs to be a close up so I can see the mount to verify it is right.

Powerman
04-25-2018, 09:59 AM
I tried to upload photo but can’t get it to work

sonoma
04-25-2018, 02:32 PM
you can use something like photo bucket or one of the other free services to load the picture to then it will have a link attached to it that you can copy and paste to the posting you make here. then either it will show the picture for us to look at it or some of the items will show up when we open the page.
if you look at the 1st items of this posting you can see Booty Monster uses photo bucket to show the large piture he has posted to this area.

Powerman
04-25-2018, 03:48 PM
http://s346.photobucket.com/user/hebertben1/media/2AE25A29-3973-460E-BC9F-A2403660BCAA_zpsdv69pwqk.jpeg.html

sonoma
04-25-2018, 03:55 PM
well I can not see the picture for some reason. my addblocker keeps killing the picture. never had that before

Powerman
04-25-2018, 04:14 PM
I have no idea

Powerman
04-25-2018, 04:21 PM
http://s346.photobucket.com/user/hebertben1/story

sonoma
04-25-2018, 04:22 PM
take you ohm meter and touch the bottom of the antenna bracket and the top of the antenna bracket and see if you have continuity between the top and bottom portions. unhook the coax to check this. let us know what the reading is.

sonoma
04-25-2018, 04:34 PM
the picture finally came up. that looks right the way it is mounted. what antenna are you using when the swr is high.

Powerman
04-25-2018, 04:38 PM
Yes I have continuity

Powerman
04-25-2018, 04:40 PM
FS4-B Four Foot Tunable tip CB antenna (Black

sonoma
04-25-2018, 04:52 PM
if you have continuity between the top of the stud to the bottom of the stud you are shorted some where and this will give you high swr. it should not be shorted. what size is the hole you have the stud mounted in? if it is too small you will short the system out. the plastic washer has a shoulder on it and the shoulder should fit inside the hole to insulate the top portion from the body. some of the holes are only 3/8 of a inch in diameter and the hole needs to be 1.2 inch to allow clearance so it does not short out. I felt you were shorted since the swr pegged out.

Powerman
04-25-2018, 05:43 PM
I as able to get below 2.5 compared to well above 3

sonoma
04-25-2018, 06:15 PM
if you have continuity between the top and bottom portion of the antenna connector it is shorted and will never drop any lower. it should show as a open circuit when you check for continuity. make sure the paint is cleaned off the bottom of the bracket on the cycle so that portion will make a good ground. the top portion should not short to ground at all with the coax disconnected.

Powerman
04-25-2018, 06:57 PM
I don’t have continuity

sonoma
04-25-2018, 07:19 PM
you just told me you had continuity in your post just before my last one.

here is what you said.
Yes I have continuity

Powerman
04-25-2018, 07:29 PM
Had continuity

BOOTY MONSTER
04-26-2018, 08:13 AM
LMAO .......

is the black paint under the mounts contact area removed so there is direct metal to metal contact ? is that piece of metal electrically connected to the frame of the 4x4 ? try this ..... cut a 9 ft piece of wire , connect it to the ground side of the antenna mount and extend it away from the 4x4 and check your vswr . just checking to see if your 4x4 is large enough to be a ground element for the antenna .......

sonoma
04-26-2018, 09:29 AM
good idea Booty Monster.I have ran out of ideas to get info on this setup. he said he had continuity on the connector then said he did not have it. so I am at a lose on this one. maybe you will get it figured out.

Powerman
04-26-2018, 01:38 PM
Added wire to ground side has channel 1 at 1:1 and channel 40 at 1:2

sonoma
04-26-2018, 03:59 PM
good job getting it down to a good reading.

BOOTY MONSTER
04-26-2018, 06:36 PM
.... too small of a ground element . on mobile antennas the vehicle is the other half of the antenna , the ground element .

Powerman
04-26-2018, 08:00 PM
I hear ya. I tried it again without the wire on the ground side my swr stayed lower than with the ground wire weired

BOOTY MONSTER
04-26-2018, 08:27 PM
lower than 1.1 and 1.2 ? interesting ........ what antenna are you using ? what meter are you using ? may not have had the mount installed correctly .

Powerman
04-26-2018, 08:32 PM
1:1 across every channel

Powerman
04-26-2018, 09:13 PM
FS4-B Four Foot Tunable tip CB antenna (Black right now but gonna use my 102” whip when I get it out my attic

BOOTY MONSTER
04-27-2018, 07:05 AM
glad you got it tuned in

Powerman
05-04-2018, 10:19 PM
I switched antenna to my 102” whip but do I need to add a spring or not?

BOOTY MONSTER
05-05-2018, 03:34 PM
if your vswr is still good without it , nope . always check vswr when changing antennas or adjusting anything on the mount .

Powerman
05-05-2018, 05:00 PM
All I have is a 3” spring when I ad the spring it slightly lowers is but it’s above 2

222DBFL
05-07-2018, 08:44 AM
You need the other 3” of spring it sounds like. If the VSWR moved down when you added the 3” spring, you appear to be headed in the right direction if the VSWR was higher without the spring. 3” more is a lot when you consider how close to 108” total length you are with the 3” spring. I would venture to say that with a 6” spring the VSWR should be pretty good if mounted and installed correctly. JMHO.

Powerman
05-07-2018, 08:54 AM
I been looking for a 6” spring I still can’t find a true 6” spring.

sonoma
05-07-2018, 08:58 AM
agree that you need a 6 inch spring to lower the swr. the antenna was actually designed to run with a 6 inch spring for for a total of 108 inches. I have the same setup that I use from time to time and it is about 1.1 to 1.2 with the spring installed. with out the spring mine gets to over 2.5.

sonoma
05-07-2018, 09:00 AM
I see them on ebay a lot. in fact about 1 month ago I bought one to replace my old spring. make sure the one you get is the 6 inch spring. some of the sellers have only a 4 inch spring. it needs to be the barrel spring 6 inches long. just looked and found the 4 inch witch does not work well. I bought one years ago and it was not as strong of a spring compared to the 6 inch spring.

BOOTY MONSTER
05-08-2018, 08:57 PM
springs that have the braided wire in the middle are to be avoided since those small wires making up the braid can easily corrode and loose their conductivity . a solid 6 inch or longer riser would be another option you may want to consider .