[CQ-Contest] CW pitch

[Dick Green]

I was just reading the QST ad for the new MFJ Speech Intelligbility
Processor. There's some interesting stuff about how different portions of
the audio spectrum contain different levels of speech energy and contribute
differently to speech intelligibility. Their point is that 1000Hz-4000Hz
contains about half the intelligibility, but only a tiny percentage of the
energy. They claim that there is less ability to detect high frequencies
with ages (true), and that this leads to loss of inteligibility (I'm not so
sure that's true at frequencies as low as 4000Hz, but maybe it is.) For the
moment, I'll ignore what the introduction of products like this says about
age demographics in the amateur community!

But the ad set me to wondering whether there are similar intelligibility
tradeoffs with CW. For several years after I got my license, I tended to
keep the sidetone pitch in the 700Hz-1000Hz range -- usually the default
factory setting, which couldn't be changed easily (or at all) on earlier
rigs. My Elmer happened to have a rig that allowed pitch adjustment, and he
tended to set it a lot lower -- and complained that mine was set too high.
When I finally got a modern transceiver, with easily adjustable pitch, I
started setting it lower and lower. I read somewhere that it's easier to
zero beat a lower frequency note because small frequency differences are a
larger percentage of a low note than a high note. Also, it seemed to make
sense that as I age it should be getting harder to hear the higher notes
(again, I'm skeptical that oldsters have significant problems at 1000Hz.)
These days, I tend to use 500Hz-550Hz. But I've noticed during contests that
when two signals are about equal in intensity, my attention is almost always
drawn to the one with higher pitch. Also, I find when zero beating that I
almost always tend to err on the high side. It appears that my mind has an
idea of what pitch it considers normal for CW and I can't retrain myself.

It seems to me that I should set the pitch at whatever frequency I find most
intelligible. Even though many contesters sadly lack the skill to zero beat,
a very high percentage of contacts will be made with those who can do it.
What's the opinion out there about this subject? Are there any inherent
advantages to higher or lower frequencies? Are there any good ways, other
than random testing, to determine the best pitch for optimum
intelligibility?

73, Dick WC1M


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