[TowerTalk] 5 db required to see?

[John Langdon]

I think we are talking about two different things here.  As the hippies used
to say "everybody's right, man!"

I think that one dB can make a difference in DXing or contesting.  But I
also know that in an over the air measurement protocol, differences between
two antennas of 3 dB or less are not easy to measure consistently.  There
are lots of changing conditions that will introduce a lot more than 3-5 dB
of "noise" into the measurements, and it would take lots of "N" to integrate
these things out, and there is a lower limit that you just can't get out.

Saying that after extensive on the air trials that you can tell that a given
antenna is 1.5 dB better than another, is like dividing two numbers measured
with 2 digit precision and stating your result to 7 digits of precision - it
just ain't there.

Also, at any given time any antenna can seem to outperform another, and it
is only a single anecdote, not a measurement.  Whenever someone with a
tribander beats out a four stack of monobanders in a contest pileup, the "my
little tribander is just as good as a stack" myth is formed.  Never matter
that the two stations are a hundred miles away, that they were on two
slightly different calling frequencies, and timings, and ... ad infinitum,
the kernel of the myth is there.  This is an emotional response in denial of
the law of large numbers, and is the same thing that makes otherwise
intelligent people play the lottery and draw to an inside straight against a
probable full house.

73 John N5CQ




-----Original Message-----
From: owner-towertalk@contesting.com
[mailto:owner-towertalk@contesting.com]On Behalf Of alsopb
Sent: Wednesday, May 24, 2000 11:49 AM
To: Towertalk@contesting.com
Subject: [TowerTalk] 5 db required to see?


I lost the original e-mail.  However, I believe it was W8JI who stated
one needed 5db type improvements to see much of a difference.

About 3 weeks ago I saw a presentation by the owner of Force 12.

His conclusion is that 2db is a BIG difference.  He had some decent
theoretical arguements and emperical contest data from 6Y5A which
supported this.  I don't think it was because he wanted to sell more
of his bigger antennas.

It appears at 2db one uncovers a whole new layer of people to work
(especially during contests) and many additional contacts on a given
band can be worked as a result.

My own meger experience is consistent with his conclusion.

By the way if you already own a 4 element monobander, getting that
extra 2db can be costly.  If you've already got stacked arrays, it's
very costly...

73 de Brian/K3KO

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