[TowerTalk] Power limitation for N-Connectors

Steve Katz stevek at jmr.com
Wed Apr 19 16:19:42 EDT 2006

>There is no problem with correctly assembled N connectors at these power 
levels; but there is a risk of failure if the centre pin is not mated 

This can happen when N connectors with a floating centre pin are used 
with  semi-airspaced cables whose centre conductor is free to move 
inside the cable. A hanging length of cable, and/or some flexing in a 
rotator loop, can sometimes pull the centre pin partly out from its 
socket, causing high resistance (especially at UHF where skin depths are 
smaller) and failures at high power.

The solution is always to use connectors that have a captive centre pin, 
and to take care when installing cables that have a floating centre 
73 from Ian GM3SEK       

::I agree with this entirely.  However, another good way to assure the
center pin doesn't retract from its mate is to use a 360 degree drip loop in
the cable.  That way, "gravity" is greatly reduced to only the weight of
half the loop, and not a long run of cable going down a tower leg.  Doing
this, I've never seen a pin retract.  -WB2WIK/6

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