[TowerTalk] Coax, conduit and toroids

Jim Brown jim at audiosystemsgroup.com
Wed Jun 27 09:08:12 PDT 2012

On 6/27/2012 6:02 AM, Ian White GM3SEK wrote:
> Ah, the joys of southern California...
> In this climate, outdoor connectors are something to be used only when
> absolutely essential.

The annual rainfall in my Northern California redwood forest averages 70 
inches, all of it between October and June. I have LOTS of outdoor 
connectors, but we learn how to weatherproof them.

I agree with Jim Lux -- simply connectorize at the tower base.

Another point.  My bifilar choke designs (which are simply a short 
length of parallel wire line wound around a single #31 toroid) will 
handle full legal ham power levels if the common mode voltage is 
reasonably low -- that is, if the system is reasonably close to balance 
-- and they are excellent chokes.  I developed these designs 
specifically to minimize the cost of the choke for places where it was 
expensive to buy the cores, and was based on your experience in the UK. 
Power handling can also be increased by using two or more chokes in 
series, as we are talking about here -- one at the top and one at the 

73, Jim K9YC

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