Topband: Quarter wave sloper on crank up tower ?

[Jim Brown]

Hi Jim,

There are many ways to skin that cat. It's pretty well known that radial 
systems don't need to be anywhere near ideal to work. The radial system 
for my Tee vertical covers about 220 degrees. In 19 years, I have 173 
confirmed on topband.

These are slides for a talk I've done at Visalia, Pecificon, and to 
several clubs. Mostly it talks about radial systems and other 
counterpoises.

http://k9yc.com/160MPacificon.pdf

Also, losses due to SWR, (SWR is determined by the match between the 
antenna at the feedline) are pretty low at 160M, especially for 
decent-sized coax, even for fairly long lines. What matters is then 
matching the transformed impedance to the power amp.

Freeware called SimSmith is quite good for designing matching networks 
for measured complex impedance sweeps of the antenna in the shack. EZNEC 
is quite good at designing antennas if given all the relevant data, 
including significant surrounding objects and a first approximation of 
soil characteristics. Rudy Severns, N6LF, has done a lot of extensive 
and spectacularly good work on radial systems. Settle into a comfortable 
chair with coffee or a nice scotch.

https://www.antennasbyn6lf.com/

https://www.antennasbyn6lf.com/design_of_radial_ground_systems/

73, Jim K9YC


On 5/6/2025 9:15 AM, jim.thom jim.thom at telus.net wrote:
> Has anybody used a 1/4 wave sloper (for 160m, aprx 120-130')  hanging from
> the top of a 89' crank up tower before ?
> Due to the 5 x sections overlapping, the feed point would have to be at the
> very top of the  tower.  IE:  it can't be part way down from the top.
> 
> Will it work with some top loading, like a 3 el  40m yagi ?   Right now, my
> modified F12 340N  yagi has all 3 x els  insulated from the boom. ( oem LL
> wire loading replaced with hb  3/8" tubing coils).    I was seriously
> thinking of bonding the REF and  DIR to the boom, to increase  the top
> loading. REF is aprx 59' long.  DIR is aprx 52' long.
> 
> I  can't shunt feed the tower, since grnd mounted radials are out of the
> question.   House is blocking the path of any radials  >  180 degs.
> 
> Jim   VE7RF
> _________________
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