Setup Same for the past 4 years which is:
Mirror mount wilson 2000 5" shaft and wilson gum drop mount.
Mounted on mirror of peterbilt 379 at angle
8' RG8X astatic coax
Cobra 29 ltd chrome edition (yes the chrome edition is slightly different than the classic"
Radio has been acting up past couple weeks so i swapped in a new coax, new antenna and new mount.
Astatic mic crapped out on me today so installed a roadking 56
When i initally installed all my stuff years ago, i did so with my buddies good external swr meter and got my readings of 1.2 on channel 1 and 40. And to be honest, the cobra built in meter was pretty much dead on.
Move ahead now, installed new components and tuned my new antenna last week with just the cobra swr. I have loud and clear 1.2 readings. I come in loud and clear for miles and transmit same way. I went ahead and bought a cheap 20 dollar astatic swr meter to verify, and the unit is telling me that my swr is in the red at 4. I figured maybe it was defective and forward at ref were reversed. but that wasnt the problem. I borrowed my buddies unit again. Low and behold readings of the same 4 swr.
Whats going on here? The mic crapped out and also antenna light will blinking when transmitting. Grounds are great and cleaned the mirror grounds and have good ground plane. Also checked my ohms on the grounds. IS my cobra going out? Just doesnt make sense becuase its loud and clear but every so often i will get a bunch of static
External swr meter has me confused
Discussion in 'CB Radio Forum' started by Don379, Oct 28, 2021.
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Your biggest mistake is trusting the cobra 29 swr readings to adjust your new antenna. I had a fellow company driver complain about his new cobra 29LX not receiving or getting out very good. The Wilson antennas on his truck were rusty at the mounts and coax connectors. My antenna analyser showed a very high swr reading of 5 - 6 for swr. No surprise there. The cobra 29 swr meter showed a reading of 1.2. That seems to be the magic number for swr readings with these radios, no matter what the real swr is. The swr vr6 pot inside the cobra 29's are always out of adjustment from the factory.
I would trust the cheap truck stop external swr meter any day before the cobra internal swr meter. I'm confused by what you mean by loud and clear 1.2 swr reading on your radio. You claim your getting out and receiving good, but that doesn't explain the high swr reading with the external meters. Did you install the coax connectors on the coax yourself? There's a problem in your antenna system somewhere. Never trim and tune an antenna by the radios swr meter. At least not the cobra 29s.
Well what good is a thread if you dont return back with the conclusion.
I took night stlker and ridgeline advice.
I hooked up a different antenna and was getting correct readings off the external swr. Was also getting same readings from cobra cb swr.
Heres where it gets weird. I dont know if it has something to do with the wilson gumdrop mount or what. I only had to trim 1/4 inch off my last wilson,
I actually had a spare whip in my shop. So i started by hacking 1/2 inch off whip. The external meter id not budge off of 4. So i said the hell with it and hacked 2 inches off. The swr now went below 3. All in all, i took off a whopping 3 inches or a little more. Thats a little redculous. Anyhow, i have 1.1 swr all across the board with the external meter now. Now the cobr internal meter is reading incorrectly at above 1.5.
Hope i didnt fry my radioTimin770 Thanks this.
craig_sez Road Train Member
- Sep 5, 2013
Try all your old gear then keep adding the new to see where the change occurs..
Possible that its the piece of coax your useing with the cheap swr meter...
Did you chk your grounds(bond points) with a multi meter,are you doin the old ground from bracket to chassie bs cause thats wayy wrong if ya are..
As cars n truck get older rust and corrossion build to so keep that in mind..
Replace all your bond straps(assumeing your not useing awg as gnd wire)
Your gnd is not goin from ant bracket to chassie or battery right?
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