high SWR
05-23-2008, 06:38 AM
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high SWR
I got a question. I put a SWR meter on my cb and i cant even get it to cal to where it needs to be. When i check the swr it red lines on all channels. I can hear some people talking (some are hard to understand) and people hear me. One guy even said it sounds real good. What would cause a really high reading? I tried a new meter and got the same thing. I dont want to ruin my radio. I am a newbie at this stuff. This is my first cb. Thanks.
Last edited by high-octane; 05-23-2008 at 06:40 AM.
05-23-2008, 07:03 AM
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Swr
Have you adjusted the needle when you're in the Calibrate mode? Adjust the needle to read on the highest hashmark while you're holding the mike key. Then switch to the SWR setting and observe what happens when you again press the mike key.
05-23-2008, 01:08 PM
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assuming that you are using the swr meter correctly, the most likely cause is not having the antenna isolated from the mounting bracket.
where do you have your mounting bracket at? if it is just bolted to the tailgate, or tire carrier, then it may not be grounded properly.
the mounting bracket itself must be grounded, but the antenna has to be isolated from the bracket so that the antenna is NOT grounded. every time i have helped a friend with this problem, it was because the nylon used on the mount was not in the correct position to isolate the antenna.
take a look at these pics from firestik.com:
here are the pieces you should have:
they can be mounted in one of the two following ways:
make sure you have the antenna mounted correctly, and the mount bracket PROPERLY grounded.
and see if that fixes the problem.
where do you have your mounting bracket at? if it is just bolted to the tailgate, or tire carrier, then it may not be grounded properly.
the mounting bracket itself must be grounded, but the antenna has to be isolated from the bracket so that the antenna is NOT grounded. every time i have helped a friend with this problem, it was because the nylon used on the mount was not in the correct position to isolate the antenna.
take a look at these pics from firestik.com:
here are the pieces you should have:
they can be mounted in one of the two following ways:
make sure you have the antenna mounted correctly, and the mount bracket PROPERLY grounded.
and see if that fixes the problem.
05-23-2008, 01:54 PM
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assuming that you are using the swr meter correctly, the most likely cause is not having the antenna isolated from the mounting bracket.
where do you have your mounting bracket at? if it is just bolted to the tailgate, or tire carrier, then it may not be grounded properly.
the mounting bracket itself must be grounded, but the antenna has to be isolated from the bracket so that the antenna is NOT grounded. every time i have helped a friend with this problem, it was because the nylon used on the mount was not in the correct position to isolate the antenna.
take a look at these pics from firestik.com:
here are the pieces you should have:
they can be mounted in one of the two following ways:
make sure you have the antenna mounted correctly, and the mount bracket PROPERLY grounded.
and see if that fixes the problem.
where do you have your mounting bracket at? if it is just bolted to the tailgate, or tire carrier, then it may not be grounded properly.
the mounting bracket itself must be grounded, but the antenna has to be isolated from the bracket so that the antenna is NOT grounded. every time i have helped a friend with this problem, it was because the nylon used on the mount was not in the correct position to isolate the antenna.
take a look at these pics from firestik.com:
here are the pieces you should have:
they can be mounted in one of the two following ways:
make sure you have the antenna mounted correctly, and the mount bracket PROPERLY grounded.
and see if that fixes the problem.
I have this setup. http://www.quadratec.com/products/96080_402.htm
I will check that after work. I didnt take it apart. I just assumed it was assembled correctly. But we all know what that gets us.
Last edited by high-octane; 05-23-2008 at 02:00 PM.
05-23-2008, 02:25 PM
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are you check it with a swr meter ot the meter in the radio
I dont trust the meters in the radio I have taken swr meters hooked them up to the radio and compared to the radio meters and none of them have ever been anywhere near the meter I hooked up
if its a seperate meter make sure you have the meter hooked up right one side is going to be the antenna and the other side is for the radio
they cannot be used either way only one way
if it is hooked up wrong after you calibrate the meter and go to check swrs it wil peg the meter
I dont trust the meters in the radio I have taken swr meters hooked them up to the radio and compared to the radio meters and none of them have ever been anywhere near the meter I hooked up
if its a seperate meter make sure you have the meter hooked up right one side is going to be the antenna and the other side is for the radio
they cannot be used either way only one way
if it is hooked up wrong after you calibrate the meter and go to check swrs it wil peg the meter
05-23-2008, 02:32 PM
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are you check it with a swr meter ot the meter in the radio
I dont trust the meters in the radio I have taken swr meters hooked them up to the radio and compared to the radio meters and none of them have ever been anywhere near the meter I hooked up
if its a seperate meter make sure you have the meter hooked up right one side is going to be the antenna and the other side is for the radio
they cannot be used either way only one way
if it is hooked up wrong after you calibrate the meter and go to check swrs it wil peg the meter
I dont trust the meters in the radio I have taken swr meters hooked them up to the radio and compared to the radio meters and none of them have ever been anywhere near the meter I hooked up
if its a seperate meter make sure you have the meter hooked up right one side is going to be the antenna and the other side is for the radio
they cannot be used either way only one way
if it is hooked up wrong after you calibrate the meter and go to check swrs it wil peg the meter
It wont even calibrate to zero. I got it to work once the first time i checked it. it read about 2 on 19. After that it just pegs the meter on all channels.
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05-23-2008, 06:51 PM
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Ok this is what i found. I tested the continuity between the coupling nut and the ant mount. I got 4 olms. This is supposed to be open right? Would this cause the SWR meter to peg out? Thanks guys.
05-23-2008, 09:04 PM
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This is from "My Cobra 75 CB and antenna install" thread.
I hope this helps.
First make sure your antenna good metal ground plane. It possible use a magnetic mount in the middle of your car roof. If you have a trunk like or similar peripheral mount, made sure you remove some paint under the screw that holds the mount to the car body so you will have a good ground. You may have to run a ground wire from the antenna base to a screw i the car body for a good ground. If you antenna is on the tail gate or other hinged door, you may have to install a ground strap from the tail gate to the body for a decent ground.
If a ground plane or grounding does not solve the problem use an ohmmeter to check the resistance between the center conductor and the shield (or threaded sleeve on the connector) on the cable. If you measure 0 ohms, then you have a short in the cable, probably in the connector. You should try to solve the problem by insalling a new connector. Careful, it is easy to short them out when soldering. If that is OK, then measure the resistance of the center conductor from end to end. If you do not get zero ohms or thereabouts, then you have a broken conductor and the entire cable will need to be replaced.
If those tests prove out, you antenna may be so long that the minimum SWR in outside the 40 channels on the radio. Flip thorugh the channels with the mike key down and SWR meter connected to see if the SWR goes down at all. If you find the swr lower on channel 1 than on Channel 40 then, the antenna is way too long. Continue shortening the antenna or adjusting the tuning slug until the SWR min moves to the desired channel (often 20 in the middle of the band) the 1-40 channel range. If the SWR is lower on Channel 40 than Cahnnel 1, then the antenna is way too short. If you have an antenna that is tuned by cutting off a piece of the radiator wire, then buy another antenna and start over. Otherwise, fiddle with the tuning slug to get the SWR min within the 40 channel range of the radio.
If a ground plane or grounding does not solve the problem use an ohmmeter to check the resistance between the center conductor and the shield (or threaded sleeve on the connector) on the cable. If you measure 0 ohms, then you have a short in the cable, probably in the connector. You should try to solve the problem by insalling a new connector. Careful, it is easy to short them out when soldering. If that is OK, then measure the resistance of the center conductor from end to end. If you do not get zero ohms or thereabouts, then you have a broken conductor and the entire cable will need to be replaced.
If those tests prove out, you antenna may be so long that the minimum SWR in outside the 40 channels on the radio. Flip thorugh the channels with the mike key down and SWR meter connected to see if the SWR goes down at all. If you find the swr lower on channel 1 than on Channel 40 then, the antenna is way too long. Continue shortening the antenna or adjusting the tuning slug until the SWR min moves to the desired channel (often 20 in the middle of the band) the 1-40 channel range. If the SWR is lower on Channel 40 than Cahnnel 1, then the antenna is way too short. If you have an antenna that is tuned by cutting off a piece of the radiator wire, then buy another antenna and start over. Otherwise, fiddle with the tuning slug to get the SWR min within the 40 channel range of the radio.
05-24-2008, 12:24 AM
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Alright. I think i figured it out. I checked the cable with an olm meter. When i tested from the center of the coax (whatever that is called) to the outside threaded portion i got like 4.7 olms. I think this is supposed to be open (i.e. read infinity on the meter) Am i correct? Im going to call quadratec and see if they wil send me another one. Would this cause the problems im having? Thanks for the help guys. 
