[TowerTalk] 1/4 slopers & Radials

[K8RI on TT]

On 9/14/2011 1:19 AM, Kelly Taylor wrote:
> I suspect the differences in half-sloper performance are related to what one
> poster here (I think it was W8JI, but forgive me Tom if it wasn't you)
> referred to as the half-sloper's inherent unreliability as an antenna
> design.

I would agree.
The half sloper is fed at the top with one half being the wire and the 
other half being the tower which is top loaded.
This puts the low impedance at the top even though the one leg is 
grounded at the base.  So the tower and wire are fed against each other 
with top loading.

 From this I would expect radials to be relatively ineffective, BUT due 
to the wide variety of configurations such as tall towers, short towers, 
large top hats, small top hats, and the variations in the included angle 
all bets are really off making each one an individual.

I use a 100' 45G with a lot of top loading and a wire that is resonant 
at roughly 1.850 or so. I think that is about 130' (give or take a tad) 
and I've had good results with it relatively speaking.  IOW I wasn't 
disappointed.

73

Roger (K8RI)

>
> I wonder if it's because depending on the actual installation, how it
> actually plays differs. Could it be that if it's fed against an insufficient
> top hat (yagi), or at the wrong height, or at the wrong angle, or installed
> while the user is wearing the wrong colour socks or whatever, that instead
> of acting like a top-fed 1/4-wave, it actually excites the tower as a form
> of a vertical instead?
>
> That might explain why some people swear by radials (they're actually
> exciting the tower as a vertical) while some see no difference.
>
> I know I've seen posts here where people praise the half-sloper as the
> greatest thing since the spark-gap while others said they ended up getting
> much better performance by replacing it with a plain, old inverted-vee.
>
> Either way, one of the beautiful things about this hobby is the process of
> discovery and finding out for yourself.
>
> 73, kelly
> ve4xt
>
>
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