[Elecraft] CW Pitch Resolution

[Sverre Holm (LA3ZA)]

There is a study from 1992 that tested recognition rate vs pitch frequency.
Unfortunately only a few tones were tested, but at least one can infer that
a low tone is preferrable. This is in Montnemery, Peter, Bengt Almqvist, and
Sten Harris. "Recognition of telegraphy signs at different listening levels
and frequencies." Scandinavian Audiology 21.4 (1992): 255-260.

The abstract is:

"The recognition of telegraphy masked by noise at 40 and 80 signs/min
telegraphy speed was studied in 10 normal-hearing subjects at different
sound pressure levels (25–85 dB SPL in steps of 5 dB) as well as at
different test frequencies (2000, 1000, 800, 630, 500 and 250 Hz). The
ability to recognize the signs varied with varying SPL. Recognition for most
of the subjects was best at an SPL close to 70 dB. All subjects improved
their recognition as the frequency was lowered to 500 Hz, some even at 250
Hz. These facts should be taken into consideration when training telegraphy
operators as well as in the construction of radio receivers to permit
listening at low frequencies. Furthermore, the critical ratio was calculated
at the different test frequencies.

Read More: http://informahealthcare.com/doi/abs/10.3109/01050399209046009"

Based on this result, it would be interesting to zoom in on the frequencies
between 250 and 500 Hz for further testing, also higher speeds would be
interesting to test as 40 and 80 is the same as 8 and 16 wpm. Peter
Montnemery is by the way SM7CMY.



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Sverre, LA3ZA

K2 #2198, K3 #3391,
LA3ZA Blog: http://la3za.blogspot.com,
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