Antenna mount question
09-11-2016, 01:22 PM
#21
JK Enthusiast
Question for the CB gurus.
Backstory first.
In our club 4 of us purchased the Cobra 75 in a group buy. We also purchased 18' coax and 5' Wilson fiberglass antennas mounted with Rugged Ridge tailgate mounts with extra ground wire. All these radios were set up and checked with SWR meter. Mine for instance is at 1.0 and 1.1 at 1 and 40.. Reception is so pathetic we hardly use them. GMRS even works better so we all carry Walky's. We are totally line of site and even at 1/2 mile seeing others we cannot communicate. We were told that up north here there is so much interference that even truck drivers no longer use CB.
So we have gone to VHF with a dedicated Jeep Chanel (and logging truck channels) that allow us to communicate up to 25klm without the use of repeater service.
So the question is: If I am getting SWR readings of 1.0 and 1.1 @ channel 1 and 40. Why do I get pathetic reception? Your opinions please.
Backstory first.
In our club 4 of us purchased the Cobra 75 in a group buy. We also purchased 18' coax and 5' Wilson fiberglass antennas mounted with Rugged Ridge tailgate mounts with extra ground wire. All these radios were set up and checked with SWR meter. Mine for instance is at 1.0 and 1.1 at 1 and 40.. Reception is so pathetic we hardly use them. GMRS even works better so we all carry Walky's. We are totally line of site and even at 1/2 mile seeing others we cannot communicate. We were told that up north here there is so much interference that even truck drivers no longer use CB.
So we have gone to VHF with a dedicated Jeep Chanel (and logging truck channels) that allow us to communicate up to 25klm without the use of repeater service.
So the question is: If I am getting SWR readings of 1.0 and 1.1 @ channel 1 and 40. Why do I get pathetic reception? Your opinions please.
Secondly, the Cobra 75 is a very poor radio in my opinion. I bought one because I was in a hurry preparing for a trip with friends. it was in stock locally, and it looked cool to have the small form factor. SWR was good, the radio just suffered from poor transmission, reception and bad audio quality for both tx/rx. I also had a nice Cobra external speaker to help with receive audio clarity. It was better than the small speaker in the mic but could not make up for the bad rx. I had the chance to switch vehicles during the trip and used regular, non-compact, Uniden and Cobra radios. it was clear that the Cobra 75 performance was significantly inferior.
I did did more research after I got back home and learned the transmit amp is in the mic handset, not in that little box with power and coax connections. Had I known that beforehand, I would not have bought it. Having the RF being transmitted through the curly mic cable is fundamentally a poor design. I'm a telecom engineer by trade and an Extra class ham. I won't claim to know everything, but I'm fairly well versed in this area. I replaced the 75 with a Uniden 520xl that cost cost roughly half as much and it does great. The difference was dramatic. Same coax, mount and antenna.
Im sure someone will chime in about their success with the unit, but mine is in a closet somewhere. I would give it away but would feel bad giving someone the problems that go with it. It beats no radio at all and might be useful in a zombie apocalypse if it is all I had. For a jeep, I encourage folks to skip this radio and find a place to mount a small regular CB.
09-11-2016, 04:15 PM
#23
JK Newbie
Join Date: Aug 2016
Location: Madisonville , Texas
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I just installed the Uniden 520XL with a 4" tunable firestick and am getting 1.1-1.2 SWR. After relocating the ground btw.
So far I have been pleased. It is on a spare tire mount as well. Eventually I may move it but for now it does what I need it to.
So far I have been pleased. It is on a spare tire mount as well. Eventually I may move it but for now it does what I need it to.
09-11-2016, 04:50 PM
#24
JK Enthusiast
I'm not pushing Uniden particularly, though I've seen the 510/520 do well for lots of folks as a simple basic CB.
I do miss the NOAA weather radio function the 75 has, I can be a bit of a weather junkie. That was handy a few times when I was outside smartphone data coverage. Though I have other gear to receive NOAA, I did find it handy being included in the CB. I think Canada has a similar / comparable weather radio system.
Good luck with your choice.
I do miss the NOAA weather radio function the 75 has, I can be a bit of a weather junkie. That was handy a few times when I was outside smartphone data coverage. Though I have other gear to receive NOAA, I did find it handy being included in the CB. I think Canada has a similar / comparable weather radio system.
Good luck with your choice.
09-11-2016, 05:11 PM
#25
JK Enthusiast
I save my real RF tweaking for my ham stuff. CB is too long of a wavelength for a truly optimal mobile installations that you can drive on city streets
09-11-2016, 06:14 PM
#26
JK Newbie
Join Date: Aug 2016
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With a good ground and low SWR, I'd leave it alone and just use it. If you are really into tweaking things and just want to experiment, by all means, tinker with it.
I save my real RF tweaking for my ham stuff. CB is too long of a wavelength for a truly optimal mobile installations that you can drive on city streets
10-14-2016, 10:02 AM
#28
JK Freak
I just used my Yeasu FT-8800R mobile in my Rubicon with the ham antenna located in the rear on an Arizona Rocky Roads mount that brings the antenna above the spare tire. The receiving and transmitting signals were VERY strong through different repeaters up to 30 miles away with me at several different locations.
I even used my handheld Yaesu VX-5R walking around with the same repeaters up to 30 miles away. I received and monitored very well. My transmission was a little weak but legible, even with the OEM little antenna. And the battery lasted fine for the 2 days I was out.
I didn't use my CB and did not have my CB antenna on the other Arizona Rocky Roads mount.
I even used my handheld Yaesu VX-5R walking around with the same repeaters up to 30 miles away. I received and monitored very well. My transmission was a little weak but legible, even with the OEM little antenna. And the battery lasted fine for the 2 days I was out.
I didn't use my CB and did not have my CB antenna on the other Arizona Rocky Roads mount.
10-26-2016, 03:33 AM
#29
JK Enthusiast
Join Date: Nov 2012
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I just installed this mount, and here's a tip.
There is a +\- 1 1/2" diameter hole with the rear window washer hose going through a rubber gromet, it's in the picture provided with the mount install instructions.
It won't fit the "to radio" connection of the antenna wire, but if you unhook the "to antenna" end, (it ships with the wire attached), the wire can be fished up and through the hole, then just slit the grommet to accept the wire.
I fished a boot lace to the area near the clutch pedal and pulled the "to antenna" end up. I then ran the wire under the carpet over to the middle of the interior.
No drilling was required, and the grommet went back in nicely.
I imagine that even if you don't have a hard top the grommet will be there.
There is a +\- 1 1/2" diameter hole with the rear window washer hose going through a rubber gromet, it's in the picture provided with the mount install instructions.
It won't fit the "to radio" connection of the antenna wire, but if you unhook the "to antenna" end, (it ships with the wire attached), the wire can be fished up and through the hole, then just slit the grommet to accept the wire.
I fished a boot lace to the area near the clutch pedal and pulled the "to antenna" end up. I then ran the wire under the carpet over to the middle of the interior.
No drilling was required, and the grommet went back in nicely.
I imagine that even if you don't have a hard top the grommet will be there.