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Author Topic: Install antenna coax  (Read 3140 times)

Craig Hauber

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Install antenna coax
« on: October 26, 2010, 04:27:10 pm »

What's the best bulk coax for installing remote antenna lines for wireless mic systems?
Getting really tired of opening plastic-wrapped pre-made cables, straightening them out and trying to fit through smaller tubes without breaking the bnc on the ends?

I've been told that RG-58 isn't the best for this, and I've also seen coax that's close to half-inch diameter and as stiff as pvc plumbing tube!

I try to keep the runs under 100' but am frequently really close to that length.

Easy field termination would be nice too -I really like compression-type connectors for video lines -can they be used for RF?

thanks for any recommendations.

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Craig Hauber
CSA Productions Inc.
Ventura-Santa Barbara CA
www.csaproductionsinc.com

Adam Kane

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Re: Install antenna coax
« Reply #1 on: October 26, 2010, 09:04:59 pm »

We usually use Gepco V5010. It's big and stiff, but we've done runs 100+ft with passive paddles and the receivers show full signal during use.

http://www.gepco.com/products/proav_cable/video/coax_50ohm_F .htm

We use crimp-style connectors (can't remember who from)...can't say as I've seen compression-style, but they may exist.

I can tell you that we just had a job last year where the original installing contractor put two Audio Technica paddles about 125' from the dist. amp and the mics barely worked with the transmitters on "RF HI" and only in certain parts of the stage could you use them without dropout. We got to looking and they used the Gepco V5020 instead of V5010 (the V5010 was spec'd but evidently part no's got mixed up or something). We went in and pulled that stuff out and pulled in the V5010. Without changing antenna positions/aiming they were now able to use the mics on "RF LOW" outside the building (2000 seat venue) without dropouts. Needless to say, anywhere on the stage is fine.

I think at the frequencies used in that venue, the V5020 (or similar cable from other companies) has about 10-11db of attenuation or so at those lengths. Although it is a lot easier to work with for shorter (25'-ish) lengths and still works.

I'm sure someone with a lot more RF wisdom than myself will chime in...this is just what I've used successfully in the past.
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Brad Weber

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Re: Install antenna coax
« Reply #2 on: October 27, 2010, 07:56:20 am »

The run length, required rating, operating frequency of the wireless systems, etc. can impact what is required but the Times Microwave LMR-400 series is pretty much an industry standard for UHF systems (http://www.timesmicrowave.com/content/pdf/lmr/22-25.pdf).
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Brad Weber
muse Audio Video

Bruce Burke

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Re: Install antenna coax
« Reply #3 on: November 12, 2010, 07:01:08 am »

Brad Weber wrote on Wed, 27 October 2010 07:56

The run length, required rating, operating frequency of the wireless systems, etc. can impact what is required but the Times Microwave LMR-400 series is pretty much an industry standard for UHF systems (http://www.timesmicrowave.com/content/pdf/lmr/22-25.pdf).



I second this. Crimp/solder type connectors are available for this coax. It is stiff though as the center conductor is solid copper plated aluminum. You can get it at places like Talley. You'll want the 50 ohm variety:

http://www.talleycom.com/store/results.jsp?csrch=_root&c srch_id=1621&csrch_page=0&csrch_sby=PartNumber,Manuf ,LongDesc&csrch_sdr=desc
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Craig Hauber

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Re: Install antenna coax
« Reply #4 on: November 12, 2010, 05:01:42 pm »

So I ordered the times microwave cable with appropriate connectors for it as per their recommendation.

Thanks for the help, but what is RG212 -that's what Sony recommended after we ordered,  and how much variance is there between it and lmr-400?

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Craig Hauber
CSA Productions Inc.
Ventura-Santa Barbara CA
www.csaproductionsinc.com

Henry Cohen

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Re: Install antenna coax
« Reply #5 on: November 12, 2010, 05:40:32 pm »

Craig Hauber wrote on Fri, 12 November 2010 17:01

So I ordered the times microwave cable with appropriate connectors for it as per their recommendation.

Thanks for the help, but what is RG212 -that's what Sony recommended after we ordered,  and how much variance is there between it and lmr-400?



LMR-400 specs here. Being a double shielded (braid over foil) design, LMR-400 has better attenuation specs.

RG-212
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Henry Cohen
Production Radio Rentals
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"Every new radio emitter since Marconi’s 2nd transmitter has caused interference to other systems!" - Michael Marcus, Oct '07

Bruce Burke

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Re: Install antenna coax
« Reply #6 on: November 13, 2010, 06:56:57 am »

Henry Cohen wrote on Fri, 12 November 2010 17:40

Craig Hauber wrote on Fri, 12 November 2010 17:01

So I ordered the times microwave cable with appropriate connectors for it as per their recommendation.

Thanks for the help, but what is RG212 -that's what Sony recommended after we ordered,  and how much variance is there between it and lmr-400?



LMR-400 specs here. Being a double shielded (braid over foil) design, LMR-400 has better attenuation specs.

RG-212


LMR-400 is a larger diameter, which is what gives it the lower attenuation specs. RG-212 is a variety of RG-58.
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