[TowerTalk] High VSWR

[Jim Thomson]

Date: Sun, 1 Sep 2019 22:26:39 +0200 (CEST)
From: "dj7ww at t-online.de" <dj7ww at t-online.de>
To: "towertalk at contesting.com" <towertalk at contesting.com>
Subject: Re: [TowerTalk] High VSWR

Jim, 

You did not mention before that the installation of a vane becomes necessary when you mount the boom at it?s center!
##  vane NOT  required if boom  mounted at  center.   Counterweight  IS  required....at  light end. 


With the boom just mounted at it?s center, the wind pressure on the boom will be much higher on the side with the longer elements whatever counter weight you place on the side with the shorter elements and cause turning force on the antenna..
##  Longer  eles... and  number  of  eles  has  nothing to  do with with it.    Each  ele  is  symetrical...so  the  eles  are  already tq  balanced .    If  wind  hits the  eles  at  an angle......  and  viewed from  above...  left  side  of  eles  bends CW.....
meanwhile right  side of  ele  bends  CCW...... they  cancel out......  or  vice versa.   The  eles  are  still  tq  balanced. 

##  I tried  this  experiment.   40  ft  boom.....  mounted   at  exact center  of  boom....to  mast.  Only  ONE  20m  ELE USED...THE REF.....  mounted   of course, at extreme  end of  boom.   no  counterweight used  for  this  test.   No  coax,  no  rotor.
Does  not  rotate,  nor ....weathervane,  etc.   Stays  put,  regardless  of  windspeed,  or  where boom  was oriented by  hand.    

Jim   VE7RF


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