[222mhz] Cost/performance...WX Proofing Connectors, CATV Line Connectors

[Robin Midgett]

Hello Jerry, Chris, list readers,
On the subject of weather proofing: the tape & Scotch Kote process has be 
used successfully for many years. I have also used another method that I 
find to be superior because it is much easier to remove when you must open 
the connection, and no messy Scotch Kote or coax seal is involved.
The first layer is Scotch 70, which is a silicon rubber based tape, light 
gray in color. It has no adhesive, but sticks to itself. This is followed 
by a layer of Scotch 33 or 88, whatever is your choice, simply as a 
protective layer for the silicon rubber. If access is required, you simply 
peel or cut the layers off. I've opened connections made with silver plated 
connectors (N & PL-259) after six years of outdoor use under these tape 
layers and found the silver just as shiny as when installed. There were no 
signs of moisture or corrosion at all. There has been a man selling Scotch 
70 at very reasonable prices ($2-$3/roll) in the flea market at Hamvention 
for several years. I stocked up a few years ago.

I've been using CATV line for many years also, in conjunction with the 1/4 
wavelength transformers that were offered by W8ZD. He is out of the 
business now but the transformers can be made quite easily if a person is 
determined to do it. These are documented on the web with some variations.
Jerry: I'd like more details on the brass interfaces you make for CATV 
line. Do you have any problems with dissimilar metals corrosion at the 
interface with that method? That has been an issue for me. Despite the use 
of No-Al-Ox, I sometimes get corrosion at the copper-aluminum interface on 
the transformers.
I've seen another version using a stainless steel collet between a 1/4 wave 
length transformer of copper and the aluminum CATV line jacket. The author 
(a CATV tech) states that is the way the cable company does it; so I think 
it must be very reliable. This method is documented on the repeater builder 
web page.

At 09:28 AM 12/1/2003, Dr. Gerald N. Johnson, electrical engineer wrote:
>For sure Scotch tape as the last layer in a mutliple layer tape/'kote system.
>
>I make a tapered thread collet for the outside connection of the CATV 
>line. Works well. All brass.
>
>73, Jerry, K0CQ
>--
>Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
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Thanks,
Robin