[TowerTalk] Take off angles, VOACAP, etcf.

[Guy Olinger, K2AV]

The problem with the experiment is that which mode is open, or how 
MANY modes are open and which one(s) being used, may not be 
determinable or selectable unless both ends have an antenna with a 
very narrow vertical aperture.

The typical ham yagi stack comes nowhere near the required narrow 
vertical aperture.

Also, if one digs around trying to find an iron-clad proof that a 
take-off angle of 15 degrees produces an incoming angle of 15 at the 
other end, one comes up empty. As best I can tell, that's an 
assumption. Not blatant in the sense of irresponsible, just that 
there's nothing else to do. If you don't pick equal angles, what DO 
you pick and why?

This problem continues to revert to the general lack of ham available 
narrow angle transmitting and receiving equipment. If we had the 
stuff, we'd just MEASURE the angles and all the speculation would 
cease.

Guy.

----- Original Message ----- 
From: "Richard (Rick) Karlquist (N6RK)" <richard at karlquist.com>
To: "TowerTalk List" <towertalk at contesting.com>
Sent: Sunday, October 17, 2004 10:40 PM
Subject: RE: [TowerTalk] Take off angles, VOACAP, etcf.


> Has the following experiment been tried?
>
> Suppose you have 2 stations with stacks.
> Skip is long, so that propagation is better
> with both stations on their upper antenna,
> compared to both stations on their lower antenna.
> Now compare propagation with one station
> on the higher antenna and the other on the
> lower antenna.   According to the theory
> that the take off angles at both ends of
> the QSO must be matched, the mismatched
> configuration should be even worse than
> two low antennas.  It would also be interesting
> to see if the mismatched case is reciprocal
> (ie the high station goes to his low antenna
> and vice versa).
>
> I suspect this theory might be true for
> one hop paths, but not hold for multi-hop,
> ducting, etc.  I used to hear W7RM with
> his stack on 20 talking to OH stations
> with similar stacks, but I am not aware
> of him publishing any results.
>
> Rick N6RK
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