Hi Herb.
I'll bet that 1/2 wave sloper worked great! When this thread got started, I
modeled several verticals in EZNEC from 1/4 wave to 5/8 wave in height. I
sent the plots around to folks that were interested via e-mail. Couldn't
post them here on the reflector. At the request of Carl, KM1H,I also modeled
the 3/8 wave case.
The 3/8 wave vertical was, indeed an excellent antenna, according to the
models, as was the 1/2 wave vertical. At 5/8 wave, though high-angle lobes
appear with some dips in the elevation pattern. I would expect that one
might get an acceptable match to a 3/8 wave vertical with a simple series
capacitor and a perfect match with a series C and a shunt C.
73,
Charlie, K4OTV
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Herb
Schoenbohm
Sent: Thursday, September 26, 2013 11:33 AM
To: topband@contesting.com
Subject: Re: Topband: 5/8 wavelength vertical is mo betta than
shorterversions??
I was very fortunate to have a 308 insulated Blau-Knox self supported
tower in my back yard with 120 radials all 250' long, in the later 70's
and early 80's and when the radio station was off the air at midnight
able to match this monstor well with a tuned circuits at the base.
Results were very discouraging as I expected it to rock and roll on top
band and it didn't. Instead I hung a 1/2 wave center fed 45 degree
sloper from a rope to the top with the tower as an untuned periodic
reflector and zounds! Being able to work 10 watt G-stations (I think
this was their power limit at that time) and many other Eu stations made
me convinced that a 5/8 wave vertical, even over an excellent ground
wasted energy at none optimal radiation angels. Their appeared on the
books a very high angle lobe which is not useful for DX plus significant
radiation below 10 degrees. I am not sure where the too low angle is on
160 but something was definitely wrong. The sloper changed all that. I
also believe, and I hope I am right, that an excellent efficient
vertical height for top band is a 3/8 wave vertical. It is also very
easy to feed with just a series capacitor to tune out the inductive
reactance.
Herb Schoenbohm, KV4FZ
On 9/26/2013 10:52 AM, Mike Waters wrote:
> A lot of hams on 160m have been similarly "shocked". :-)
>
> 73, Mike
> www.w0btu.com
>
> On Thu, Sep 26, 2013 at 9:37 AM, Niko Cimbur <ac6dd@yahoo.com> wrote:
>
>> We were shocked to find that the existing 1/4 wl performed better than
the
>> much taller [5/8 wave] Vertical.
>>
> _________________
> Topband Reflector
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