[TowerTalk] Optimium Tower Height

[Don Tucker]

Hmmm, I do believe I was just put down!

Don W7WLL
----- Original Message ----- 
From: "David Gilbert" <xdavid at cis-broadband.com>
To: "Don Tucker" <w7wll at arrl.net>
Sent: Wednesday, May 19, 2010 11:07 PM
Subject: Re: [TowerTalk] Optimium Tower Height



Being able to "work what you can hear" is an almost worthless criteria
for judging an antenna, and for the life of me I can't understand why
hams keep using it as if it meant anything.

1.  The difference between a kilowatt and operating barefoot is at most
two typical S-units, so by definition 98% of everyone out there is
running essentially the same power.

2.  Except for some unique situations, propagation is essentially
symmetrical and path loss is pretty much the same in both directions.

So unless you simply have a really inefficient antennas (lots of
resistive loss), you're going to have similar results no matter whether
you are receiving or transmitting, and so will the guy on the other end
of your QSO.  If you change from a dipole to a yagi you will gain a few
db on both transmit and receive and your peformance for both will
improve.  Change the height of your yagi from 50 feet to 100 feet and
your antenna pattern for both transmit and receive will change
identically.  The relevant criteria is the percentage of stations you
can work out of the total that are on the band, not the percentage of
them that you can hear.

I can work everything I can hear when I have nothing but a dummy load
and ten feet of wire connected to my rig, but that doesn't make it a
good antenna.

73,
Dave   AB7E





On 5/19/2010 10:39 PM, Don Tucker wrote:
> I'm using the same antennas, with the A3WS 8 feet above the TH7DX. The TH7
> is at 72 feet and performs well. I can usually always work what I hear.
>
> Don W7WLL