[TowerTalk] re 25G base insulator

[Rob Atkinson, K5UJ]

Hi,

AM broadcast stations don't use 25 all that often so insulators for it are 
kind of unusual.  Rohn used to make a bottom taper and insulator so you 
might give them a try, or whoever is making the R25 hardware these days.

Because the station wants to use 25, I'm making a few assumptions--the tower 
is going to be around 90 degrees and in the higher part of the band so it 
isn't very tall; maybe not even lamped and painted.   You say the f/p I is 
5.5 amps.  Assuming a f/p Z of around 36 ohms it looks like a 1 KW station 
(this has nothing to do with the insulator--I'm just having some fun).   I 
would be a bit uncomfortable with separate leg inulators at the base.  Any 
AM R25 tower is still gg to be pretty tall for the face width.  I'd look 
into Austin insulators for a single point ceramic insulator and see if they 
have anything.  They took over making the Lapp line I believe.  A small 7 
inch long Austin might be the ticket depending on the download.

http://www.austininsulators.com/radio/product.html

btw, AM tower sections are often tac welded together.

73,

rob / k5uj

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