[TowerTalk] RG11 Cable

[Jim Brown]

On Tue, 25 Aug 2009 14:16:06 -0400, Carol Richards wrote:

>After searching for many years for a source of CATV cable, the Gods 
must have been shining on me today. The local cable company had run a 
300ft piece of line temporarily until they founf the problem. I asked 
for the cable and not only did they give it to me, but promised more 
each time they were in the area. The cable is 1/2 inch RG-11, foam with 
a quad shield. I have several questions and I hope the readers out 
there can help....

This is NOT RG11, it is much better than RG11 (MUCH lower loss). It 
will also handle a lot of power. 

>1. Could I use the crimp type PL-259 with this cable?

There are special connectors and tools made for it. You need them. 

>3. Since the cable is 75 ohm and all of my antennas are 50 ohm, how do
>I match this cable (easily) . I run legal limit.

A high dipole is inherently a 70 ohm antenna. While most commercial ham 
antennas are designed as 50 ohm antennas, the WORST CASE additional 
loss due to a 50/75 ohm mismatch (1.5:1 VSWR) is 0.18dB.(There are 
equations and graphs in the ARRL Handbook and ARRL Antenna Book that 
clearly show this. Any reasonable antenna tuner will easily handle that 
small mismatch, and so will any amp with a tunable output stage (most 
high power tube amps). 

>4. Are there commercial transformers that will handle the power 
>readily available? 

They are called antenna tuners. :)  The Ten Tec 229-series and 238-
series are very good manual tuners that handle full legal power. See 
the product reviews on the ARRL website for good automatic tuners. 

73,

Jim Brown K9YC