Topband: ~ 1/4 wave 160 doublet

Donald Chester k4kyv at hotmail.com
Fri Oct 24 01:21:32 EDT 2003


I can tune my 80m. open wire fed dipole on 160, and it works pretty well.  
The tuning is very sharp; +/- 10 kHz at the very most.  I had to make some 
additional feedline to add in to the feeder to get optimum length.  I 
started out midway between a high voltage and high current point with the 
feeder tapped down on the coil, and it was very inefficient, and the air 
variable in the tuner would arc over at 100 watts or so, even though the 
plate spacing 3/16" is rated at 7000v.  I adjusted the feeder length for a 
high voltage feedpoint, and with parallel tuning, I can run 1000+ watts with 
no arcovers.  It is wery sharp tuning, but doesn't arc over.

I use a true balanced tuner with split stator air variable and link coupled 
air dielectric coils.  I wouldn't even consider trying it with the bogus 
method that uses an unbalanced  T or L network feeding a balancedi tuned 
feedline thru a balun.

Don K4KYV

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