Cobra 29LX and Wilson Little Wil- SWR Help (Extremely High)

[Allof75]

This might sound silly, but you didn't cut the coaxial cable to length right? I've done that before and chased my tail for a while. Make sure not to coil up the excess cable and run it throughout the cabin as well.

Like everyone said before check the grounding plane. One step you can try if you have access to a multimeter/VOM is to check continuity between a good known ground and the mount.

With the multimeter you can also test your coaxial cable by checking continuity between the center conductor and outer shield, you should have none if you do then something is wrong with the cable.

Hopefully you can get it setup properly.

Also if you get this far it is helpful to know:

If SWR is higher on channel 40 than channel 1 then your antenna is too high.
If SWR is higher on channel 1 than channel 40 then your antenna is too short.

I did not cut the coax, I think at this point I will just try to return it and swap for a firestik hardmounted to somewhere on the body. But thank you for the other information, if this continues to be an issue with a new antenna I will definitely refer to it.

 

[Frdmskr]

Yeah that checklist is good. I'd do a 30 second continuity test. See if you have a broken connection in the coax, antenna base or the magmount. I had a VHF multiband antenna go sideways once because the tab cracked and no longer was closing the circuit between the center conductor of the NMO and the antenna itself. That was annoying (and why I don't use those antennas anymore.)

 

[ReconZJ]

Just read through this thread and wanted to offer that I'm in HB and have a Midland SWR meter and a Cobra mag mount antenna that I use on my new GC. I'm willing to help you out if you want to troubleshoot a bit more, before going with a Firestick (I have one of those on my other Jeep, and it's been great).

 

[Allof75]

So I scrapped/set aside using the Wilson antenna completely and went for a Firestik setup, heavy duty spring, 4' black antenna, quick release and door jam mount which I put on the rear, next to the tailgate. I ran the coax, and soldered the connection, tested for continuity as described in the manuals, and still have the high SWR, now with a nice little "Antenna Warning" message on the screen of the CB. I'm calling Cobra tomorrow, this is ridiculous.

I now have an SWR tuner, and have a shorty coax coming in the mail for testing. Thank you for the help again, I'll keep y'all posted.

 

[ReconZJ]

Mounting it on the door jam may be the problem - lack of a proper ground plane. I used to have my ZJ's Firestick mounted on my Con-Ferr roof rack, and when I took the rack off, moved the antenna to a rear tire carrier mounting location. While I still have an ok SWR, it isn't nearly as good as being on the roof. And, my distance has decreased significantly, to the point where if I'm tailgunning a large group and we get spread out, I can't contact the leader. Since I used to have very good tx and reception on the roof rack, I know that the antenna location is the problem.

 

[Allof75]

Mounting it on the door jam may be the problem - lack of a proper ground plane. I used to have my ZJ's Firestick mounted on my Con-Ferr roof rack, and when I took the rack off, moved the antenna to a rear tire carrier mounting location. While I still have an ok SWR, it isn't nearly as good as being on the roof. And, my distance has decreased significantly, to the point where if I'm tailgunning a large group and we get spread out, I can't contact the leader. Since I used to have very good tx and reception on the roof rack, I know that the antenna location is the problem.

I know there can be some issues with running it back there, in my case I mounted it relatively high on the rear hatch, and it's a 4' antenna instead of 3, so I have at least a good 2' above the roof. I had considered mounting it on the roof, but considering I'm changing my rack options shortly, and there were very very few places that I'd trust (I'm definitely not willing to drill through the roof for something like this), I went with the mounting location I did. Rear hatch mounting I wouldn't think would cause horrible SWRs, otherwise the good number of other pathfinder owners that have it in the same location wouldn't have done it in the first place. But anyway, thank you for the pointers.

 

[Allof75]

I spoke to Cobra today, and their "technician" initially tried laying the blame on the antenna, but after convincing him that I had checked every single connection on the setup, he relented and said it was an issue with the unit. Sounds like it's the common problem of the "Antenna Warning" light going off like crazy with the 29 LXs, all it takes is a little adjustment. So I'll fiddle with it, and for now he mentioned it's safe to broadcast and transmit, so that's exactly what I'll do. :elkgrin: I'll keep this thread updated if anything else happens. Thank you for the help again.

 

[4x4junkie]

I now have an SWR tuner, and have a shorty coax coming in the mail for testing. Thank you for the help again, I'll keep y'all posted.

I'm guessing you meant meter (not tuner)... For sure update us on what it says after you get it. That should say for sure whether it's the radio's built-in meter out of calibration, or if your antenna infact still has an issue.

 

[Allof75]

Sorry it's been a long week, yes I meant meter haha. So I hooked it up yesterday to the unit in the most open area I could find, and I was getting a reading of about 2.7. I adjusted the tip on the antenna a couple times, sanded the paint under the mount away to make sure it was grounding, and that was the lowest I could get. For comparison the SWR meter on the cobra was below 1.5, so obviously something is wrong there. I'm open to any and all suggestions regarding tuning, I've done all the connectivity tests and what's considered proper setup so far as I can tell, so I'm left scratching my head. Do door jam mounts typically need an extra wire for grounding, or is metal on metal good enough?

At this point, I would be willing to take it to a CB shop in the area, so if someone has any recommendations for one in Orange County CA, I would be much obliged. PCI Race Radios seems well reviewed.

 

[4x4junkie]

Metal on metal should be good enough as long as it's a substantial mass of metal it's attached to (door jamb or pillar should be good... The door itself or on a tire carrier, likely wouldn't though).

Got a pic of your antenna setup? Maybe that might help someone to offer additional suggestions. Perhaps it simply needs to be mounted up higher or something (at least 60% of the antenna's length should be clear of the vehicle).

 

[Allof75]

Here's my setup, it's a 4' antenna, so by far the majority of it is above the roofline and extends beyond the fenders. I've also noticed that it moves quite a bit at highways speeds despite having the HD spring. I've checked with firestik and I even got the hookup order correct on the firewire to antenna.

 

[BigJimCruising]

What's that piece of metal below the spring and above the mount?

 

[k9lestat]

Its a quick antenna disconnect.

I'd lose that from the set up if I was you. I never have heard anything good about them.

 

[4x4junkie]

I'm somewhat inclined to agree in this case.
There are a couple good-quality quick-disconnects out there (the Hustler QD-2 and Breedlove come to mind), but the length such a device adds to the antenna on top of having the spring could be contributing to why the SWR isn't matching up (guessing it's probably a little lower on CH-1 than 40?).

Any chance you can move the mount up higher? (say in the middle or up near the top of the door pillar)?

 

[Allof75]

The piece in the middle is a quick disconnect as mentioned. If I'm going to hard mount it (after drilling holes in the body I'm set on that) then I need a disconnect to get into the parking garage at my work. Are there some brands which are recommended above others? This one is the K-1 made by Firestik, and I bought it thinking it couldn't do much harm considering it was made by the same company as the other components.

Unfortunately the mount can't move any higher because that's the only spot which a rear-mounted antenna would have enough clearance between it and the rear hatch. As it is, it's more than halfway up the rear door, and I don't want to have to drill more holes than necessary.

Thank you so far guys, I'll take out the disconnect and see if the SWR improves much.