Topband: Topband resource

[Jim Thomson]

Date: Wed, 15 Jan 2020 15:58:57 +0000 (UTC)
From: Roger Parsons <ve3zi at yahoo.com>
To: topband at contesting.com
Subject: Re: Topband: Topband resource

<W8JI's experience with a horizontal dipole at 300 ft is often quoted as proof that only vertical antennas are useful for 160m DX. This is not my experience with a dipole with the centre at 320 ft and the ends at over 250'. In its favoured directions it is equal to a <W4RNL half wave vertical array over a very large radial system. It is unsurprisingly not as good off the ends, and quite is useless for relatively local communications.
<I am also inclined to support Roger, G3YRO, in his use of a low dipole, having myself successfully used relatively low horizontal antennas for DX in the past. There are most certainly times when higher angles are useful for DX - and possibly more frequently than <we imagine. There actually have to be, otherwise Roger would never work any DX at all. Note, this does not mean that a good vertical antenna is not often or even usually better than a low horizontal one. Finally, the UK is small compared to many other <countries, but it is not actually a tiny island. Roger's path to North America is over about 300 km of land, and he is more than 10km from the sea in any direction.

<73 RogerVE3ZI/G3RBP

##  AFAIK,   W8JIs..  dipole  was  actually an  inverted   vee,  with the  apex at  300  feet....with  no  info  on  enclosed  angle.  
Per  the  older  arrl  ant  books,  Inverted   vees...with a 90  deg  enclosed  angle  are  omni directional. 
But  they  conducted  that  test  on  80m,  with an  inverted  vee    up  60 feet,  with a 90  deg  enclosed  angle.  The  vee  was  rotated 90  degs....
and  signals  900  miles  away  did  not  change.  No  mention  whether a real  CM  balun  was  used.   

##  Plenty  of 80m  rotary  dipoles and  80m  yagis that  perform  exceptionally well..at  heights  of 100-150  ft.   That  would  extrapolate to   200-300  ft
on  160m.    Years ago,  a fellow In  Ore  had  installed   the  1st  F12    160   rotary  dipole....  which  I  believe was  up aprx  120  ft.     His  1st  contact  
was a 4X4.   Several  folks  with  2 el....shorty 40 yagis  up  70  ft,  report  that  the  shorty  40  yagi ate  their   40m  4  squares  hands  down. 
Some  have  had  great  success  with  a half  wave  sloper......used in  conjunction  with a delta  loop  reflector...apex  up.   In  some  cases, a half  wave  sloper
was  used  on  either  side of  the  delta  loop  REF.   So 2 switchable  directions  were  obtained.  

Jim   VE7RF