Topband: 5/8 wavelength vertical is mo betta than shorterversions??

[Charlie Cunningham]

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 at contesting.com] On Behalf Of Herb
Schoenbohm
Sent: Thursday, September 26, 2013 11:33 AM
To: topband at 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 at 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

_________________
Topband Reflector