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Coax Cable to use for UHF GMRS band
Posted: Tue Jan 10, 2006 7:09 pm
by nyscan00
Hi Im in the process of setting up a GMRS base station, but was wondering what type of coax cable to use for GMRS UHF band from radio to antenna ..... RG 59 or similar? The entire cable run should be no more then 50' .
Thanks
Posted: Tue Jan 10, 2006 7:14 pm
by RadioSouth
I'd say RG/213U ideally but RG8 is more readily available in rat shack and would be OK in a pinch. Not RG59.
Posted: Tue Jan 10, 2006 7:47 pm
by tvsjr
Ugh...
RG59 is 75 ohms. No bueno.
RG213 and RG8 suck, especially the drek from Rat Shack.
Personally, I'd look at LMR-400, unless you're looking at continuous duty/repeater ops, which would need Heliax.
Posted: Tue Jan 10, 2006 8:57 pm
by Bat2way
Low Loss Belden 9913 RG8/U Air Cable
or
LMR-400
Posted: Tue Jan 10, 2006 10:09 pm
by tvsjr
9913? Nothing like coax that can be used for RF and for a garden hose, all at the same time!
Posted: Tue Jan 10, 2006 10:50 pm
by jim
LMR400.....cheap, easy to work with, connectors are cheap and it performs well at UHF.
Posted: Wed Jan 11, 2006 7:27 am
by RadioSouth
Darnit, meant 9913 not 213 which isn't good for much. But yeah LMR-400 looks even better, haven't used it yet but I'll give it a try after I run out of the 1/2" heliax assemblies I picked up on fleabay, super deal picked up a doz. in assorted lengths that came out to about a buck a foot, brand new.
Posted: Wed Jan 11, 2006 8:20 am
by wa2zdy
The day you take the connector off the back of your radio and there's water dripping on the floor, you say "what the . . ..?" Then you know why 9913 sucks.
LMR400 is the way for a base. The other stuff, especially RG58 is WAY too lossy at 462 MHz. That would just be wasting RF and not being able to hear much either. Pointless.
Posted: Wed Jan 11, 2006 8:21 am
by AEC
Are you serious about using oddball lengths of cable here?
I hope not...the transition losses will be great.
9913: Dry location, no troubles.....other than that...can you say water ingress?
LMR-400 is a great choice, low loss, low cost alternative to Heliax.
50 foot runs.....Just buy 250' of 7/8" and be done with it.
Never cobble cables, fastest way to trouble.
If all you need is 50 feet, I would use at least 75, the added loss will be negligible and you leave enough length should cabinet relocation become a necessity in the future, they do make hangers for comm shacks that will allow for this.
You'll need a good jumper cable too, to transition from the larger cable to the rack, for flexibility. Most mfgrs. have jumpers in 5 and 10 foot lengths.
Since you doing this, get a few grounding kits also, for the exterior panel and interior so you stay current with your area's code requirements.
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Posted: Wed Jan 11, 2006 12:16 pm
by Jim2121
Posted: Wed Jan 11, 2006 12:53 pm
by 440roadrunner
I think maybe 7/8 hardline is a little overkill, but certainly the likes of RG-59 (or 58) is certainly a poor choice.
So far as I'm concerned, just about ANYTHING Radio Shack calls coax is pretty poor fare---especially for VHF or UHF use.
Posted: Wed Jan 11, 2006 3:07 pm
by motorola_otaku
I'll hop on the LMR-400 bandwagon. I've used it all the way up to 900 MHz with very positive results. It's mostly a drop-in replacement for RG-8 EXCEPT for N connectors; the copper-clad aluminum center conductor is slightly larger in diameter than standard RG8 and generic N connectors won't take it. The ones from Times Microwave made specifically for LMR-400 are in the $8 range, I believe.. haven't ordered any in awhile.