[TowerTalk] Inverted Vees

[Jim Thomson]

Date: Tue, 16 Jun 2020 08:15:53 -0700
From: jimlux <jimlux at earthlink.net>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Inverted Vees

> Jim Lux wrote
> 
> These are theoretical dipoles, so infinite null.
> 
>

<The hairy ball theorem says that isotropes don't exist in the real 
<world. And neither do perfect dipoles. <grin>

<I'd be impressed by a 30 dB null on a real dipole on real supports in a 
<real environment.

##  Perhaps Grant Saviers  or Tim  Duffy  can chime in..as they both have  80m rotary dipoles ? 
To  tweak the  rotary dipole for a deep null, the  rotator would have to be going really  slow.
A  T2X, or any rotor that turns at  1 rpm  is  way too fast.  Thats  6 degs per second.
A PP is only 3 degs  per sec.  A  PP  with the green heron box can  really be slowed down,
and ditto with the  OR-2800.  The  OR-2800  can be slowed down to  .1  deg increments
on the  digital output,  like  say 89.1  and  then  89.2  then  89.3  etc.   M2  calls the  ultra  slow
mode.....  bumping. 

##  Sure, free space models  will  show a sky high, almost  infinite FS....  but practical 
dipoles are  above  dirt.  Still, if the rotor was slowed  right down,  Im betting the
null  off one end, could be  directed at one station, resulting in a  real deep null.

##  Same thing could be applied to a yagi....with offending station off one side.  Again,
the  array would have to be turned really slowly.  It would be an interesting experiment..esp for  40M broadcast.
That SW  broadcast junk on  3925  would be a  good source for a solid steady signal to experiment on.

Jim  VE7RF

Jim   VE7RF