[CQ-Contest] Re: Sloper Advice

[it9blb at infcom.it]

Jamie Dupree wrote:

> I am trying to build an 80 meter sloper for the upcoming contest season,
> and I was hoping someone in CQ-Contest-land could give me some advice. 
> 
> I don't have a tower and beam on top - I'm trying to build a sloper that just
> hangs in one of my trees in the backyard. 
> 
> I pulled a center connector almost 50 feet up - one wire is cut at
> 67 feet for 80 meters and is pulled out at a 45 degree angle. 
> 
> The other wire comes down to a ground rod, where I attached it with
> a small hose clamp and the regular screw that was on the rod. 
> 
> It gives me a 3-1 SWR,  and hears about three s-units worse than my
> inverted vee on 80.  My rigs don't really want to tune the thing,
> so I know something just isn't working right. 
> 
> I even tried running a few radials from the ground rod, but that
> only made things worse. 
> 
> If anyone has some tips, I would greatly appreciate the help,
> whether on or off the reflector.   
> 
> Thanks 
> 
> Jamie NS3T

Hi Jamie,
I had a similar experience about 10 years ago:
I tryied to have a sloper running from the top
of a 70feet high self supporting steel tower,
without (at that time) any antenna on it.
Coax's braid was connected directly to the top
of the tower and its central conductor to the
sloper going down with a starting angle of 45
degree.
After hours of experiments on lenght, position
and angle of the sloper, I understood that the
missing capacitive hat (yagi antenna/s) was a
real MUST ! I always had a extremely high SWR
and a real insensitivity to any possible change.
When, after a 5el. 20m wide spacing monoband was
on the top, I repeated the experiment, I was able
to tune the wire in just few tens of minutes;
I then setup 3 different selectable slopers at
120 degrees around the tower, with really UFB
results.
Just my little personal experience! 

Good luck, 

Joe, IT9BLB/KF6FBC/IU9S/IH9P 

http://www.ih9p.com