[TenTec] SteppIR vertical

Rob Atkinson, K5UJ k5uj at hotmail.com
Fri Oct 10 15:42:51 EDT 2003


You can't go wrong with the 88' center fed flattop and parallel wire feed if 
you feed it with a balanced transmatch.  doesn't need to be very high for 
casual ragchew operating.  in order to work as a dx antenna, has to be up 
higher.  I use that antenna (not very high up) and a Gap Titan.  The Gap is 
okay on 40, 20, 17, and 15.  It's performance falls off on its upper and 
lower limit bands.  I have augmented mine with a ground screen under it of 
20 foot long radials.   My dipole is much better for domestic ragchewing on 
the low HF bands.  The Gap is better for dx not surprisingly since it has a 
lower angle.

If I had it to do over again, I'd try the StepIR.  I would get the one that 
goes down to 40 meters and mount it in the open on a pipe about 15' high.  
I'd build a cone of radials coming down from the antenna base (feedpoint) 
all around it each 1/4 w in sequence for each band and repeating.   Then (if 
I really wanted to go all out, and this might be a good idea on dry desert 
ground) I'd put a ground screen of radials lying flat and coming out from 
the base of the pipe.  The pipe (mast) and radials would not be part of the 
counterpoise however.  The excellent thing about this antenna is it's 
ability to adjust length so you always get an impedence match between the 
feedline and feedpoint.
Besides lower loss (more important on 6 and 10) if you run QRO you don't 
have to worry as much about dielectric heating and flashovers in the feed.

A nice little side benefit is that in thunderstorms you can reel the 
vertical all the way in and have a 15' high antenna instead of one around 
45' high.

the one drawback I can think of that I'd investigate with the StepIR is the 
motor pushing that copper tape up inside the fiberglass tube.  on the yagis 
it's pushing it out horiz.  but on the vert., assuming it's not hung upside 
down, the copper tape may get hung up working against gravity.  I'd find out 
as much as possible about how it's engineered to prevent that.

Rob Atkinson
K5UJ

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