[TowerTalk] The ultimate one tower system?

[n4kg@juno.com]

IMHO,  80 to 100 ft is the perfect height for nighttime 
antennas, especially 40 / 30 / 20 meters.  This height
also works well on 15M when the MUF is below 25 MHz
(such as in Summer or opening / closing the band).  

During daytime conditions, the popular 80 to 100 ft level
SUCKS on the high bands compared with LOWER antennas,
or antennas at 115 ft +/- a few feet where the SECOND lobe
of the high antenna falls at the same waveangle as my 
favorite daytime height of 40 ft.  Note there is a deep NULL
between the first and second lobes of high antennas so
a LOWER antenna is needed to fill in the gap.

Also IMHO, everyone needs a good tribander or set of
high band antennas at 40 ft to cover ALL of the higher
angles supported by the ionosphere.  A separate 40 ft
tower with rotating tribander or 5 bander is a POWERFUL
asset.  Switching between antennas is much faster than
rotating a single antenna!  You can never have too many
antennas (until maintenance begins to take all of your time!)

One of my favorite tower arrangements is 120 ft of R45
guyed every 40 ft.  with  3 or 5 band antennas at 120 and
40 ft. and a 2L40 at 80 ft, all rotating or a rotating tower.
A 24 ft boom multiband antenna can be gamma or omega
matched as a rotary dipole on 30 / 40 meters.

Stacking gets complicated.  If your antennas are too close
you will suffer from interaction and a good multiband antenna
may be a better choice.  The longer the boom (greater gain)
the wider the optimum spacing.  Tribander stacking is 
usually a compromise when gain is the same on all bands.

The new Force 12  C31XR is a good candidate for stacking,
having higher gain on the higher bands, the optimum stacking
distance is CONSTANT.   The C3E (2L on 20/15, 3L on 10)
is also an interesting stacking antenna.

Another powerful SINGLE  TOWER  arrangement is a 70 ft 
(R25/45) tower with tribanders at 40 / 70 ft and a 2L40 at 80+ ft 
on a strong mast.  If the mast is REALLY strong, maybe even
an 80M loaded dipole nested with the 2L40.  Check your math
on the mast loading!  Supplement this with another tribander and
WARC beam or 5 bander on a 40 ft tower.  VERY  POWERFUL 
combination, especially during high sunspot activity when wave 
angles are high. Guy at 35 and 70 ft.

de  Tom  N4KG


On Tue, 14 Dec 1999 05:27:49 -0800 Michael Dinkelman <mwdink@eskimo.com>
writes:
> 
> As I evaluate my new tower and the performance of the lowly
> borrowed antenna on top, my thoughts turn towards next summer.
> We will cap off the tower with another 30' (all ready to go)
> to make it a even 100' plus 15-20 foot of carbon steel
> mast out the top. At that point, I need to populate this puppy
> with potent aluminum.
> 
> Using the cumulative brain power of this reflector, what would 
> be your ultimate system for a single tower? 
> I want this to be as contest competitive as a single tower
> can be. Stacks? Tribanders? Monobanders? Sidemounts?
> At what levels? (While I love Quads, I don't think I 
> want to try that on a guyed tower but if you're passionate
> enough - you can try and convince me anyway.) Right now, 
> the skies the limit... at least until I open my wallet. 
> (but then I can dream can't I?)
> 
> 73
> dink, n7wa
> 

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