Solid Coax in Vehicles

billyfromhill

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#1
Is solid coax OK to use in a mobile application? Laird makes the MB8X mount which has RG8X solid coax which I think I'm going to use for all my installs moving forward. I know solid primary wire is a no-no in mobile applications but I'm not sure if coax will fatigue?
 
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#2
Solid center coax is perfectly fine for mobile installs. Depending on the desired band, it is really the only option as stranded center would have to much loss.

I use the MB8X for all my personal vehicles, never a problem.

Solid wire in the 12 volt world has to do with connection issues. Example: you can't butt splice a solid wire without fear of it loosening and causing a problem, or any crimp connector. That's why you never see a crimp connector in house wiring. Also, solid wire is not flexible enough.
 
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#3
I've used LMR-240 (bought the mount by accident).
It worked fine. It was a bit stiffer than the stranded center conductor, and you'll need to be a bit more careful when you route the cable.
 

KE5MC

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#4
Is solid coax OK to use in a mobile application? Laird makes the MB8X mount which has RG8X solid coax which I think I'm going to use for all my installs moving forward. I know solid primary wire is a no-no in mobile applications but I'm not sure if coax will fatigue?
Are you sure its solid coax. If labeled RG8X none of the quick Google searches I did spec it as solid. I use it in my shack and it stranded too. I'm not saying its bad, just pointing out a possible difference in name vs. material.

Mike
 

W9BU

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#6
I've never been a fan of solid center conductor cable in mobile installations. I worry, possibly without foundation, about the vehicle's vibration work hardening the center conductor resulting in breakage.

Larsen used to offer a double shielded RG58-type cable on their mounts that I thought was worth the expense. But, I don't see it in the cut sheet you provided.

If you are worried about the different in loss between R8X and RG58, I think it is not worth worrying about in the cable lengths you find in most mobile installations.
 
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#8
How hard is it to attach your own coax to a NMO mount? Is there a guide anywhere?
Depends on the mount. The basic ones are just a solder connection. Center conductor is soldered, and the outer shield has tabs that bend around and soldered.

The -HF mounts have a soldered center conductor and a crimped shield.

Easy enough to solder your own NMO mount, even if you don't have a crimp tool. You can buy "bare" NMO mounts, or just salvage and old one.
 
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#9
I've never been a fan of solid center conductor cable in mobile installations. I worry, possibly without foundation, about the vehicle's vibration work hardening the center conductor resulting in breakage.
I've experienced a broken solid centre conductor cable in my car installation. Never had any issues with stranded. And given the shorter length of cable used in most (all?) mobile applications I wouldn't expect much of difference in performance between solid and stranded.
 
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#10
Solid center confuctor RG58 has been the industry standard for many decades and is used on virtually ever mobile installation so no, not a problem at all.
 
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#11
Everything nowadays coax wise is pretty much solid center in a vehicle. All your modem antenna's, WiFi, cellular, radio, etc have some sort of solid center coax. Usually high frequency mounts use a LMR-195 type cable, buy same physical size as RG58.

A problem with solid center is improper coax installation. If done with a knife, care must be taken NOT to score the center conductor, or you will have problems. Otherwise, I've never had a problem.
 
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#12
Proper strain relief, routing, securing, etc. prevents most issues. If coax center conductor is breaking due to movement or vibration, then that's a separate issue.

If you are using a mobile antenna with a portable radio in a vehicle, then making sure you have a stranded center conductor would be a good idea.
 

billyfromhill

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#13
Depends on the mount. The basic ones are just a solder connection. Center conductor is soldered, and the outer shield has tabs that bend around and soldered.

The -HF mounts have a soldered center conductor and a crimped shield.

Easy enough to solder your own NMO mount, even if you don't have a crimp tool. You can buy "bare" NMO mounts, or just salvage and old one.
Is there a special tool used to crimp the NMO mount to the braid?
 
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