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Current Balun Dressing

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June 21, 2021, 10:23:44 PM *
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Author Topic: Current Balun Dressing  (Read 784 times)
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Posts: 337

« on: February 19, 2021, 12:07:12 PM »

Hello to the board.

I am putting together some nice current baluns per K9YC.  They will live in a outdoor polycarbonate NEMA box, so no need for the porcelain feed through pieces.

Three options for output:

1) Large gold plated banana posts.  I like them, but fear the sun will degrade the plastic.

2) Brass 10-32 machine screws with wing nuts, lock washers, etc. Pretty, but will likely need Brasso and steel brush once in a while.

3) As above, but stainless.

Spacing will be about 1.25 inches on centers.  I am thinking an inch or more of polycarbonate is insulation a plenty.


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Posts: 438

« Reply #1 on: February 19, 2021, 12:44:42 PM »

I have installed baluns at HF installations all over the world from 1 to 50 kilowatt versions.  The output threaded rods are all stainless steel on everything I've dealt with for the past couple of decades.  Here at home, I have two open wire lines leaving the radio room on four-inch centers with ceramic and/or teflon wall-throughs.  One uses brass threaded stock, the other stainless steel and they both perform well. 
I share your apprehension about the UV stability of the plastic on those banana posts.  In the good old days of Bakelite I might say "maybe", but plastics, unless they have a pedigree, are a no-go outdoors.

73 de Norm W1ITT

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Brrrr- it's cold in the shack! Fire up the BIG RIG

« Reply #2 on: February 19, 2021, 01:52:38 PM »

They sell all metal binding posts to the audio folks.
You can get Gold, Silver, Rhodium plating.
Also just brass.

You would enclose the exterior of the BPs with "gorilla snot" aka that
rubberized "tape" that is use for waterproofing and weatherproofing by
the phone co, electric co, and sold at higher prices to hams... that obviates
the problem(s). It squishes together...

I use it on silver plated PL-259s outdoors and when peeled off they're shiny.


_-_- bear WB2GCR                   http://www.bearlabs.com

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Posts: 337

« Reply #3 on: February 19, 2021, 05:59:01 PM »

Sounds like 10-32 stainless with flats, locks, and wing nuts will do.  Probably not much loss over an inch or so.
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Posts: 1773

CW is just a narrower version of AM

« Reply #4 on: February 21, 2021, 07:45:51 AM »

Yup on the tape - ugly but it works for just about everything exposed to oxygen (including my mouth).

These are the good old days of AM
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