[TowerTalk] Shunt Feeding, Can this be?

[ersmar@comcast.net]

Pat:

     I just checked the SWR on my 160M shunt-fed tower from the shack and it's 2:1 or lower from 1.8 - 1.9+ MHz.  I don't ask questions.

73 de
Gene Smar  AD3F



> 
> I now have 30 radials installed on my tower and am shunt-feeding it through new 
> coax, an antenna switch, and a vacuum variable.  The coax run is 30ft.  The 
> tower is a 55ft crank-up with 20 ft of mast out the top and a TH7 at 56ft and a 
> XM240 at 69ft.  The shunt wire is 30 inches away from the tower and is #6 
> stranded.  I am able to get 1:1 on both 80M and 160M with my motor driven 
> variable in a Gamma match configuration.
> 
> The 1:1 reading is absolutely flat for about 60-70Khz.  It is the same on both 
> bands in as far as being flat and wide.  I thought I might have a poor ground, 
> but I have double checked all connections and resoldered everything that looks 
> even remotely bad.  I also have 15 ground rods connected to the tower on three 
> legs besides the radials.  This is my first attempt at shunt feeding a tower and 
> my question is if it is possible to have such a flat SWR on a shunt fed tower?  
> My numbers are with the MFJ are:
> 1830Khz  R=24    X=167 SWR>25  397pf on the vacuum             variable for a 
> 1:1 reading 
> 
> 3500Khz  R=24    X=295  SWR>25  157pf on the vacuum variable for a 1:1 reading
> _______________________________________________
> 
> See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless Weather 
> Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions 
> and ask for Sherman, W2FLA.
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk