[TowerTalk] Perspectve

[Wes Attaway]

After reading several of the "perspective" postings it is obvious that no
one really knows how much difference a single db makes in a contest.  There
are simply too many variables.

Maybe the only way to get even a glimmer of meaningful data would be to
construct several identical stations within a few miles of each other.  Use
1000W amps and decent beams so you will be able to work down into the lower
layers of smaller DX stations.  Then, do something (I'm not sure what) to
reduce half of the test stations to antenna gains of exactly 1-db less than
the others.  Man them with competent ops in several DX contests and check
the scores.  I guarantee you that there will be scoring differences that
will be way out of proportion to the 1-db gain differences.  If you swap the
ops around between contests you are still going to see scoring differences
that are out of proportion to the gain disparity.  A bell curve of the
scores will (I believe) center around certain ops, not certain stations.

I don't think there is any plausible way to refute the theory that 1-db of
extra antenna gain will occasionally get you a contact you would have
otherwise missed.  I do think that if the test described above is actually
carried out you will find that the operators make a much bigger difference
than does 1-db of extra antenna gain.  No DXer or contester in their right
mind would say, "I don't want an extra db".  The question really is how much
time and money is a single db worth.  So far I haven't seen any real solid
answers.


-----Original Message-----
From: owner-towertalk@contesting.com
[mailto:owner-towertalk@contesting.com]On Behalf Of K7GCO@aol.com
Sent: Wednesday, July 19, 2000 10:42 PM
To: towertalk@contesting.com; jamesd1@flash.net
Subject: Re: [TowerTalk] Perspectve



In a message dated 7/19/00 8:26:36 PM Pacific Daylight Time,
jamesd1@flash.net writes:

<<
 All - I find the discussion on trying to demonstrate what a dB is worth
 fascinating. Let me put in my $0.02pi  worth.  (pi is an irrational
number).

 A few years ago I took the Sweepstakes results and compared the  QSOs and
 sections worked for the QRP (<5W), low power (100 W), and High Power
 (1500W).

 There was no difference in the sections worked; the QRP winner had a clean
 sweep as did the High power winner, but the 100 W station missed by 1 or 2
 sections. My conclusion was that a dB didn't matter much, if at all, when
it
 came to multipliers in Sweepstakes. I haven't looked at the DX contests.

 I don't recall the exact numbers, but it seemed to me that there was a
 factor of slightly  greater than 2 in QSOs between the QRP winner and the
 High power winner. I think that the 100 watt winner was slightly in between

 There is a 13 dB difference between the 5 W and 100 W levels, and another
11
 dB or so between the 100 W and 1500 W level.

 Again the gain in QSOs between the power levels seems disproportionate to
 the power gain required, and there seems to be no advantage, at least in
 Sweepstakes, in getting more multipliers. Part of this may be due to the
 limited nubmer of multipliers in SS, and it may just take the QRP station a
 bit longer to get them all.

 I realize that this is not a serious analysis, but it does point out
trends.
 Maybe after I get done here I will go look at the 99 numbers for SS.
 Exercises in  numerology are so much fun.

 To reiterate what somebody else said, I think that careful listening over a
 period of time to the NCDXF beacons is as good a learning experience as
 there is as to what different signal levels mean. - Dr. Megacycle KK6MC/5

 The best
 --
 James R. Duffey KK6MC/5
 30 Casa Loma Road
 Cedar Crest, NM 87008
  >>
   About 5 years ago there was an article in the DX magazine comparing
antennas and another Sweekstakes example was given where the difference
between the 1 KW  and 100W top score was 40%.  On a linear basis that is
4%/dB.  This is a significant difference.   k7gco

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