[TowerTalk] Re: Can takeoff angle be too low?

[Barry Kutner]

While listening to 3Y0C yesterday on 10m, I was surprised to find 
him louder on my TH7 at 40 ft, than my TH7 at 76 ft. That's a long 
haul for a higher angle.

On an unrelated note, there's an interesting looking picture of 
someone on a tower at 
http://www.davidschoen.com/pics2/dsp021.jpg
A little dangerous with no climbing belt, don't you think?

73 Barry

On 18 Dec 00, n4kg@juno.com wrote:

> Bill,
> 
> Are you quoting from N6BV's statistics / model where
> he ASSUMED 60 ft towers at BOTH ends of the path?
> (which exhibit a NULL from 13 to 20 degrees on 10M).
> 
> That same study showed NO propagation on 20M
> from ~20 to 28? degrees, assuming 100 ft high towers,
> but an opening in the 30 degree range.  He didn't 
> seem to realize that his  Propagation Null  was coincident
> with the  PATTERN NULL  of 100 ft high antennas.
> I don't put much weight in his propagation "statistics"
> based on ioncap and fixed (high) antenna heights.
> 
> To determine the best reception angle for the LOW
> transmitting antennas that most DX stations are using,
> it would seem best to model a Low Transmitting antenna
> and look for the angle that produces the highest received 
> signal strength which is NOT the approach taken by N6BV.
> 
> During previous sunspot maximums I found my 35 to 40 ft
> antenna best to Europe and especially Africa most of the
> time once the band was open.  Several others in the area
> have made similar observations when comparing 70 to 90 ft
> high antennas with 35 to 40 ft (1 to 1.25 WL peaking at
> 12 to 14 degrees +/- 6 degrees).
> 
> When the MUF approaches 50 MHz, the ionosphere will
> support up to 18-20 degrees on 28 MHz.  For the majority
> of Europeans / Africans with antennas at 30 to 40 ft, it
> would follow that THEIR signals would peak at higher 
> angles.  My "guess", based on pattern peaks of low
> antennas and pattern NULLS of high antennas is that
> the peak angles from Europe and Africa on 10M are
> in the range of 10 to 15 degress during midday.
> 
> de  Tom  N4KG
> 

--
Barry Kutner, W2UP              Internet: w2up@mindspring.com
Newtown, PA         FRC         alternate: barry@w2up.wells.com

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