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coax question

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timmer

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Where would I buy cable such as LMR-400 with f-connectors already installed on it and how much would a run of 100 feet cost me? Thanks for any replies.
 

prcguy

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There are no F connectors that directly fit LMR-400, you would have to use adaptors. LMR-400 runs about $.40 to $.75/ft unless you get the great Ebay deal, 1000ft for around $170. There are people selling pre made lengths with connectors installed for reasonable deals on Ebay at times. What kind of run do you need? What frequency range?
prcguy
 

timmer

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I am needing about 75-80 feet. I am about to re-do my antenna tower and am currently using rg-6 cable. It does ok but with putting up new antennas and all the work that goes along with, I want to use the best cable I can. I'm trying to make sure I get it right the first time, I do not want to have to do it twice. (I am paying someone to climb the tower and do the work, I have a problem with heights and the person I have doing the work is not cheap.)
 

kb2vxa

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Hi Timmer and all,

RISC777 Doug sent me a photo of a big roll of the stuff with BNC connectors he's about to install so why not ask him?
 

buffalogoat

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If you are just using it for receiving (scanner, shortwave, etc.) you would never need a coax as big or as expensive as that! LMR-400 is a 50 ohm cable designed for high transmit power applications or long coax runs. (over 100+ feet)
I agree with the other guys, if the length is less than 50ft., go with 75 ohm RG-6 Quad Shield. If over 100ft. RG-11 is fine. (Plus, you can get "F" to "BNC" adapters at any Rat Shack store.)
 

RISC777

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Heck, if you can afford it, buy what you want. Everything I've got is either -400 or -600 regardless of length. (Well, my car has Times Microwave, but not -400 :lol:)

I saw a post somewhere that had a link to a place that sold F connectors for 3/8" cable. But you'd be soldering and crimping them on yourself. Most places that will make cables for you won't mess with an F connector on that type/size of cable. Never know though, you might find someone out there that will or does.

`Doug
 

prcguy

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The RG-11 specs at Radioware are for the mil type solid polyethylene dielectric, copper braid version, not the low loss, foil shield, foam type used in CATV. I haven’t seen that solid stuff since high school. Look up current Commscope or Belden specs. Modern RG-6 has about 35 to 40% more loss than RG-11 over the 150-1000MHz range. At 850MHz, 100ft of RG-6 has about 6.1dB loss and RG-11 is 3.98. That’s not trivial. Modern CATV RG-11 is very close to Times Microwave LMR-400 at 4.1dB for 100ft @ 1000MHz compared to RG-11 @ 4.35dB. If I had a Scantenna or other antenna that terminated in an “F” connector, I would feed it with RG-11 rather than some large 50ohm coax and a bunch of adaptors.
prcguy

N_Jay said:
There is almost no difference between RG-6 and RG-11 in loss at 100 feet.

http://www.radiobooks.com/products/techinfo/coaxloss.htm
 

buffalogoat

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I agree with prcguy... Here's the Belden specs for their 75ohm coax at 800MHz

BELDEN 8215 (RG-6) 100 feet @ 800MHz = 8.71 db loss

BELDEN 8213 (RG-11) 100 feet @ 800MHz = 4.47 db loss

When I worked for Intermedia/Northland Cable TV, we used RG-11 for any drop over 60ft. long.
 

Al42

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buffalogoat said:
BELDEN 8215 (RG-6) 100 feet @ 800MHz = 8.71 db loss

BELDEN 8213 (RG-11) 100 feet @ 800MHz = 4.47 db loss

When I worked for Intermedia/Northland Cable TV, we used RG-11 for any drop over 60ft. long.
And LMR-400 is only a little better - 3.646db loss for 100 feet @ 800 MHz.
 
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