[TowerTalk] 80 meter antenna advice. (NY6DX)

[Jim Thomson]

Date: Fri, 14 Feb 2020 13:23:30 -0600
From: john at kk9a.com
To: towertalk at contesting.com
Subject: Re: [TowerTalk] 80 meter antenna advice. (NY6DX)


<That's funny Jeff:)  In reality an 80m beam can be built strong enough  
<to survive the midwest. I had a homebrew linear loaded dipole with a  
<90+ ft element 160' high that held up well in Chicago. However if you  
<want to operate both CW and SSB, you will need relays on the elements  
<which can be problematic and difficult to maintain.

<John KK9A

##  Heres  where  loaded  elements would  be a  huge  asset...to  minimize max ele length ....  which  can  be  made  
stronger....vs a  full  sized  ele.   T  bars,  aka  capacity  hats would be a good  loading  scheme.  That  plus
loading  coils,  just  inboard  of  T bars.   The  remaining  loading, and  ability  to  switch  from  cw  to  ssb
can  be  done  with  fixed  coils  and a mess  of  relays....  or a seco  systems  tornado  drive..which is  just
a  pair  of  compressible,  plastic  coated, .25 inch od   copper  tubing  coils.  The  seco  uses  an  ameritron  SDC-102  screwdriver
controller,  12  vdc,  to  expand and  compress  the  coils.  Comes  with a  digital  readout turns  counter..and  10  x pre-sets.
Tornado  drive  installed  at feedpoint  of  each  ele. 

##  If  relays  are  used,  use  gigavac  SPDT  G2  type ceramic  vac  relays,  or  Taylor  brand V2  SPDT  ceramic vac  relays...  available
in 12 vdc  or  26.5 vdc.    If  mech  relays  have  to  be used,  use DPST  types,  with  contacts  in  parallel......  for  redundancy. 

Jim   VE7RF