Why does my Cobra 29 SWR meter say I have a flat swr on my Lil Wilson antenna and when I hook SWR meter up it says that it's above 3 what meter am I supposed to believe?
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SWR question
- Thread starter ChromeCobra
- Start date
Welcome to the forum. And, I would believe the external meter. Your may have a short to ground somewhere in your antenna system. The meter in the radio is simply reading no signal from the antenna system.
Well with the cobra 29 SWR meter on channel 1 the needle doesn't move channel 20 barely moves and on channel 40 I would say it's 1.2 to 1 or 1.3 and with the external meter channel 1 is above 2 then on channel 20 it's 1.5 to 1 and on channel 40 it's above 3 to 1 it's a brand new lil Wilson magnet mount antenna my dad even took his cobra 29 and checked for me and it showed the same as my radio is there any test I can do to check for the problem that your talking about I will take my multimeter and check the coax and see if I'm getting good ground and make sure the coax ain't shorted it's so confusing I've never had this problem before the reason it has me worried is I did a mosfet mod to my Cobra 29 and I think my mosfet is now dead cause it popped my fuse on the radio
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I was thinking you were saying the meter shot up above 3 on all channels 1 to 40. That indicates a short in the antenna system, however if Channel 1 is 2+, Channel 20 is 1.5, Channel 40 is 3+ it looks like it is too short towards Channel 40. It will need lengthened to bring the 3+ down to a safe below 2. Once you lengthen the antenna whip, to tune the antenna, you may get below SWR 2 on all 40 channels. The Lil Wil is capable of below 1.5 on all 40 channels. Where on your vehicle is the Lil Wil mounted? You may have a poor ground plane for the Lil Wil- meaning when the antenna is attached to a surface it needs to have a flat area to work as the reflector for the antenna, which acts as the ground plane. That's is the function of the radials on a base antenna- too improve the ground plane, as a base antenna without radials will used flat Earth as a ground plane. Without a proper ground plane the functional bandwidth of you Lil Wil antenna narrows- the antenna can only safely transmit on a very narrow band of channels.
At the base of the stainless steel whip on the Lil Wil there is a tiny Allen screw- unscrew and move the whip up a small bit, retighten the Allen screw. Retest SWER with the External meter. Channel 1 may go up a little, Channel 40 will come down little, Channel 20 will come up a little. Most, likely the best you will get at that location is a flat 2 across all 40 channels. You may have to try a different location on the the vehicle like the center of the roof, if possible. Some vehicles have too much fiberglass and the small mag mount antennas will only tune in the center of the roof. I am trying to cover as much as I can. Best of luck.
At the base of the stainless steel whip on the Lil Wil there is a tiny Allen screw- unscrew and move the whip up a small bit, retighten the Allen screw. Retest SWER with the External meter. Channel 1 may go up a little, Channel 40 will come down little, Channel 20 will come up a little. Most, likely the best you will get at that location is a flat 2 across all 40 channels. You may have to try a different location on the the vehicle like the center of the roof, if possible. Some vehicles have too much fiberglass and the small mag mount antennas will only tune in the center of the roof. I am trying to cover as much as I can. Best of luck.
It is in the middle of my roof on my Ford ranger only thing is I tuned it with my cobra 29 SWR meter when I purchased the radio and antenna both I drove to my local dirt track cause it has a big open field with no power lines when I first hooked it up the the antenna was showing to long and I kept trimming the stinger till I got the swr I told you with the SWR meter in the radio only reason I checked with my old swr meter is cause even tho my swr was low the antenna warning light still lit up and quick question not trying to sound fussy but if you can't trust the SWR the cobra 29 is giving it defeats the purpose of it just saying could it be possible that my external meter is wrong IDK at this point I'm fixing to go out as soon as I undo the mosfet mod I done and put the stock final back in her and take my multimeter and post pictures for ya
Back when I was 17 I made a dipole out of speaker wire and made contacts all over with a cobra 29 with a rfx75 I had installed in it back then so I just don't know I've had problems like this all my life in vehicles sometimes it was the coax and sometimes it was antenna placement it's just so confusing will post pictures for ya of testing the coax and my ground and whatever you think I should test
Its, very confusing. Over the years I have tried, the Lil Wil, K30, And a Tram mag mount. I have have best luck with the Tram mag mounts. The magnet is bit bigger. Truck cabs at difficult animals. Traditionally, we do not trust the built in meters in the radios and go with the External Meters to be more accurate. Quickly, set the Lil Wil on a car roof in the same field you were testing the Ford Ranger, before you if the soldiering iron.
I tried it on my mom's Honda Pilot and it is all the way in the corner off the scale on 1, 20, and 40 I don't know anymore I checked with a multimeter across the coax connector and its not shorted so I just don't know
I just put it back on my truck and I ain't even getting 1.5 to 1 on 20 anymore so there is something up I tested my jumper it's not shorted so idk anymore I still think it's this old meter
To know which meter to trust you might want to consider getting or making a dummy load. It should always show a flat match no matter which meter is used. Doesn't need to be anything fancy, just enough to handle however much power you're pushing.
I have a dummy load I made and the needle don't even move on the radio or my meter I'm bout to give up at the point cobra says the SWR is low meter says it's off the scale I just don't know anymore before I took it off the truck to try on Mom's car it was high on 1 and 40 and 1.5 on 20 now it's doing this
The meter in the radio is Crap & adjustable. I have seen them show terrible SWR readings & the SWR is really very good & I have seen them say they were great & they were terrible. NEVER trust the cheap SWR meter built into Any CB Radio. Keep a good external SWR meter inline.
Well with the dummy load my cobra 29 SWR meter shows the same as my old external meter when I bought the antenna and radio both bought at same time at a truck stop like I said I tuned it with the radios meter and noticed that the antenna warning light still came on that's the confusing part is why if it's high why ain't the meter showing it high I just don't know anymore troubles like this is what ticks me off and just for comparison I put a stud mount in the center of my roof with a 102 whip and it still wouldn't have low SWR only way I way able to get a flat SWR is put it on the back passenger side corner of my bed and I don't like that cause my brother told me that the signal would be stronger towards the front
And 18 foot of brand new coax was used with 102 whip if you need to know that heck my cab may not be grounded to my frame I don't know all I know is I've always had trouble with antennas on all my rangers I've owned threw my life