ARRL

Forum Home - Rules - Help - Login - Forgot Password
Members can access, post and reply to the forums below. Before you do, please first read the RULES.

QUAD SHIELD FLOODED 75 OHM COAX?

Feb 8th 2012, 08:55

WA3TJO

Joined: Feb 8th 2012, 08:41
Total Topics: 0
Total Posts: 0
Recently I had a new metal roof installed on my home and garage. My XYL "convinced" that my 4BTV should be moved away from my home. The nearest practical location is a hay barn about 110 feet from my shack. I have a roll of quad shielded flooded direct burial coax. The coax is 75 ohm. An Elmer just told me that the ONLY thing he uses to all his antennas is 75 ohm surplus cable tv cable.
The product I have would be a couple steps higher I feel. What do others think about using 75 ohm cable for a 110 foot run to a 4BTV? Note: the hay barn also has a metal roof. 73, Len in Colorado
Feb 8th 2012, 13:59

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0

The big disadvantage of CATV coax for hams is the use of aluminum, rather than copper--this means that you may not be able to use techniques that require soldering. Instead, you should use the proper crimp connectors.

Zack Lau W1VT
ARRL Senior Lab Engineer
Feb 8th 2012, 16:45

W0BTU

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Quote by WA3TJO
... I have a roll of quad shielded flooded direct burial coax. The coax is 75 ohm. An Elmer just told me that the ONLY thing he uses to all his antennas is 75 ohm ...


That's all I use too, RG-6 flooded Commscope quad-shield. I use crimp-on F connectors, too.

One thing to check is how thick the copper plating on the steel core is. If it's too thin (as I hear it is in some cheap brands), it may have significantly higher losses on the lower HF bands.

Check out these links:
http://forums.qrz.com/showthread.php?279520-RG-6-vs-RG-58
http://vk1od.net/transmissionline/RG6/

73, Mike
www.w0btu.com
Feb 11th 2012, 02:31

KB0HAE

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Hi. I would want to mount the 4BTV above the metal roof and use it as a ground plane for the antenna...though your XYL may not agree. I have always liked the old joke... "She said either the radio goes or she does...that was 2 weeks ago OM, over"
Feb 13th 2012, 07:08

WA3TJO

Joined: Feb 8th 2012, 08:41
Total Topics: 0
Total Posts: 0
Hello Everyone! Thanks so much for your advice and comments. The brand of the cable is Times Fiber. The roll is brand new but it was purchased 15 years ago! Before copper was like gold! I actually have some new connectors for it. NOW! The BIG problem is.....where the heck did I put that spool of cable! I found cable I didn't know I even owned, but for the one I'm looking for, well, I'm going to keep searching until I find it. I'm just wondering how good the grounded metal roof on our hay barn will do as far as a ground plane. I am mostly on 20m . I suppose I'll find out soon as I find the cable. Thanks again guys! 73, Len

Back to Top