[TowerTalk] Loading crankup towers?

[K7GCO@aol.com]

In a message dated 10/25/01 5:13:01 AM Pacific Daylight Time, 
RCARIELLO@si.rr.com writes:<< 
 Hello,
 With all this talk about vertical antennas let me ask this question.
 I have been told that a crankup tower will not load well as a vertical do to
 the sections not being fastened together.
 
 My thought would be to hang wires along the side of the tower similar to a
 cage dipole with the tower inside. These wires would be spaced and insolated
 from the tower. At the top the wires would be joined together. At the base a
 ring going around the tower where all the hanging wires would be
 attached.This cage of wires would be insolated from ground. Along the tower
 spacers or  rings might be used to prevent the hanging wires from hitting
 and shorting to the tower. To extend the height of the tower a vertical
 element could be attached to the wires but insolated from the tower.
  Comments please.
  Rich AA2MF
 aa2mf@arrl.net
  >>
Rich: This is a good idea and depending on how you do it, it can be used to 
obtain a real high feedpoint Z also.  Or for starters just do this.  Connect 
a insulated wire or 2 to the top of the tower and to the bottom of the tower. 
 It's just a low resistance path parallel that doesn't change resistance next 
to the tower.  Try that first for a reference and then do the cage 
construction around the tower which can give a couple of variations and it 
will increase the bandwidth.  As I just said in a previous post yesterday, 
I've not seen anyone suggest using a cage construction in over 40 years.  
Well you finally did!

I had planned a similiar construction for a 160m vertical that would give a 
600 ohm feedpoint for 600 ohm open wire line on the far end of my property.  
It would feed right into a link coupled tank circuit of my old Pr 813's final 
with the right nuimber of turns with a series Xc. That's about as efficient 
and broadbanded as one can get with a feed system.  We didn't have bandwidth 
problems even on 160M before coax and all it's balun problems. That's the way 
it was done in the Stone Age of the Last Century and it has never ever been 
improved upon.  The convenience of coax and the bandswitching 50 ohm Pi 
network of Art Collins in the 32V series and KW-1 was a step backwards in 
efficiency and bandwidth.  It is better than the 50 ohm output rigs. It has 
it's applications that I use myself but not for top monoband operations of a 
competitive nature.  

If your tower was a 1/2 wave, the feedpont Z of the cage construction would 
be perhaps around 4000 ohms +/-. It can be adjusted to a wide range of Z's 
even lower.  At the end of an odd multiple of 1/4 waves of very low loss 450 
ohm line you can make, it will give you 50 ohms balanced.  There are all 
kinds of combos on each end to get what ever Z you want.  

It appears to me from my comparisons and success with 1/2 waves with and 
without ground systems, the E field loss of a 1/2 wave in the local area is 
less than the H field loss from 1/4 waves with limited radials.  A 1/2 wave 
being already resonant lends itself to a fairly short radial system more than 
does a 1/4 wave when space doesn't permit a full 1/4 wave radial system.  The 
high current meat section of a 1/2 wave is a 1/4 wave above ground.  I will 
do a side by side comparsion this winter.

Since the finances of the average DXer are higher than ever, I cannot see 
this slavery to 1/4 wave verticals even on 160M and all this radial dialog of 
one senairo after another that never gets solved or agreed upon.  A lot of 
these problems "just go away" when you use 1/2 waves.  However I've seen that 
the great patterns of a 4 Square don't duplicate with 1/2 or 5/8 waves.  One 
would have thought the vertical patterns would have really flattened out.  
I'm working on 4 Square type and other configurations using 1/2&5/8 wave 
verticals.  Keep in touch.

Rich: Congratulations for one of the good new ideas we don't see enough of on 
TT.  Ignore those who say it won't work without trying it.  That's why so few 
are 
presented.  
        You get the 
                          "K7GCO New & Creative Idea of the Year Award "   

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