[CW] Learning hints

[D.J.J. Ring, Jr.]

Hello Fabian,

Thank you for this information - and if you think about what Fabian has said
about QRQ (fast) Morse over radio - you will realize that there is a trade
off when considering low frequencies - say 150 Hz.

One additional aspect to this is the ear-brain interface.  The brain can
separate lower pitched signals as a percent of an octave.  An octave is
twice the frequency:  100 Hz / 200 Hz is an octave, but 800 to 1600 Hz is an
octave.  The first octave is only 100 Hz wide but the second is 800 Hz wide.
 The ear-brain forms a narrower filter at very low frequencies where it can
actually notice changes of even a few Hertz (cycles per second).

Jason N1SU (TNX Jason!) has posted the "Art and Skill of Radio Telegraphy"
by N0HFF (sk) http://n1su.com/c14.htm

<http://n1su.com/c14.htm>G1OGY has this on the human ear:
http://www.g1ogy.com/www.n1bug.net/tech/w2rs/The%20Human%20Ear.doc

W8MKV wrote this:  http://www.nitehawk.com/rasmit/br_cpy.html

<http://www.nitehawk.com/rasmit/br_cpy.html>I find - and many have observed
- that when signals have to get through - I use wide 3 to 6 kHz selectivity
and tune to the very low note - as with SOS signals on 500 kHz - but often
we were copying on the "sidebands" alone - which with MCW can happen up
above 4 kHz above the carrier.

Distortion - or even (same thing) key clicks can make a signal get through -
don't tell others especially DXers about that or we'll have tons of key
clicks when some rare DXCC comes on.

73
DR

On Thu, Jan 14, 2010 at 3:06 PM, Fabian Kurz <mail at fkurz.net> wrote:

> On Thu, Jan 14, 2010 at 02:43:34PM -0500, John Seney wrote:
> > What is the best pitch to listen to CW?
>
> As usual, it depends on many things.
>
> The ear's best performance at copying Morse code at low SNRs is
> somewhere around 500Hz. There are some interesting papers on this by
> Peter Montnemery (SM7CMY) from the early 1990s in which this was
> tested with a number of CW operators. This is mainly due to anatomic
> reasons: The ear works like a filter bank; at lower frequencies these
> filters have a bandwidth of about 100Hz and get wider towards higher
> frequencies. Thus the effective SNR increases for a lower pitch with
> the same signal energy because the noise energy over the narrower
> bandwidth is lower. This is also the reason why very narrow CW filters
> are rarely useful.
>
> Using a low pitch on the radio also increases the _relative_
> frequency offset between a wanted signal and a close interferrer.
>
> The higher the speed, the closer a part of the spectrum of the keyed
> CW signal comes towards very low frequencies, which creates a bumping
> sound. Increasing the pitch helps to avoid this. This can also be
> improved by making the keying softer, but at very high speeds the
> rise- and fall-times can only be so long because the length of a dit
> is only so long. A possible solution: Add harmonics to the CW signal,
> e.g. by an amplifier with strong distortion. I actually prefer to hear
> CW signals with a sawtooth waveform over sinus when I practice with
> RufzXP or 'qrq' at very high speeds.
>
> My radios are usually set to 600Hz pitch, fwiw.
>
> 73,
> --
> Fabian Kurz, DJ1YFK * Munich, Germany * http://fkurz.net/      .---.
>          Learn CW Online: http://lcwo.net/                   |  |  |
>                                                               | /|\ |
>                                                               `---'
> ______________________________________________________________
> CW mailing list
> Home: http://mailman.qth.net/mailman/listinfo/cw
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:CW at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.qth.net/pipermail/cw/attachments/20100114/8a83dbe5/attachment-0001.html