coax question

Status
Not open for further replies.

timmer

Member
Joined
Dec 11, 2003
Messages
266
Location
Springfield, Il
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

Member
Joined
Jun 30, 2006
Messages
15,233
Location
So Cal - Richardson, TX - Tewksbury, MA
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

Member
Joined
Dec 11, 2003
Messages
266
Location
Springfield, Il
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

Completely Banned for the Greater Good
Banned
Joined
Mar 22, 2005
Messages
6,100
Location
Point Pleasant Beach, N.J.
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

Member
Joined
Jan 30, 2005
Messages
21
Location
Simpsonville, SC
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

Member
Joined
Oct 19, 2005
Messages
929
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

Member
Joined
Jun 30, 2006
Messages
15,233
Location
So Cal - Richardson, TX - Tewksbury, MA
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

Member
Joined
Jan 30, 2005
Messages
21
Location
Simpsonville, SC
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

Member
Joined
Apr 29, 2005
Messages
3,457
Location
Long Island, NY, USA
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.
 
Status
Not open for further replies.
Top