[TowerTalk] Take off angles, VOACAP, etcf.

[Jim Lux]

I very much agree.
I found ON4UN's list of stations and antennas quite interesting.

But just how deep is that null for near the horizon for the dipole at 40
feet?  In real life, I'll bet it's not all that bad.
Even if it's 20 dB down from the peak, if propagation is open, then the
proverbial 1 watt and a wet noodle will get through, particularly for a
narrow band mode like CW or slow digital, but, the other guy has to be
listening. And, of course, the propagation might only be open for a few
minutes at a time.  I admit that VOACAP isn't well suited to this sort of
operation.


----- Original Message -----
From: "Guy Olinger, K2AV" <olinger at bellsouth.net>
To: "Jim Lux" <jimlux at earthlink.net>; "W3YY" <w3yy at cox.net>; "TowerTalk
List" <towertalk at contesting.com>
Sent: Saturday, October 16, 2004 11:26 PM
Subject: Re: [TowerTalk] Take off angles, VOACAP, etcf.


> That's the d*mned if you do, d*mned if you don't issue IF you only
> publish one kind of measurements.
>
> If you don't do isotropic figures, then you can't adjust for your own
> antennas. But you ALSO need to do some runs accounting for a far end
> that has a dipole at 40 feet and couldn't transmit a signal below 15
> degrees if his life depended on it, no matter what VOACAP picks as the
> best angle for broadcasters.
>
> That's when you start to understand how higher angles are going to
> help you work the next layer of signals in a contest.
>
> Anybody can work the guy on the other end running a KW and a beam up
> 30 meters. It's his buddy down the block running 10 watts and an
> antenna draped over a couple of short trees that will test one's rig
> and choice of antennas.
>
> Guy.
>
>
> ----- Original Message -----
> From: "Jim Lux" <jimlux at earthlink.net>
> To: "Jim Lux" <jimlux at earthlink.net>; "Guy Olinger, K2AV"
> <olinger at bellsouth.net>; "W3YY" <w3yy at cox.net>; "TowerTalk List"
> <towertalk at contesting.com>
> Sent: Saturday, October 16, 2004 11:48 PM
> Subject: [TowerTalk] Take off angles, VOACAP, etcf.
>
>
> > I've been giving some thought to the VOACAP amateur radio thing..
> >
> > If you run VOACAP, it displays the dominant path (and it's takeoff
> > angle,
> > which is presumably what N6BV used in building the statistical
> > tables).
> > However, I wonder what antenna was used. If it was an isotrope, all
> > paths
> > would be weighted evenly in the selection, which will tend to favor
> > the low
> > angle one hop path, as opposed to the high angle two hop path.
> >
> > If you give VOACAP a realistic pattern typical of most ham antennas,
> > which
> > have terrible gain below a few or 10 degrees, that might favor the
> > high
> > angle two hop path, which would account for Guy's comments.
> >
> > Hmm..
> >
> >
> >
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