Sidetone questions -- copy speed vs sidetone pitch

I understand the reason a lower pitch ST would be easier to copy when qrm is present, due to the percentage difference matter.  My question concerns what pitch is easier to copy when receiving fast cw when no qrm is present.    I seem to remember seeing a post on this matter some time in the past, in which it was stated that pitch makes a difference, but have been unable to find in the archives.  Anyone remember it?
Also, it seems my K2 pitch volumn has a "hole" around 550 to 625, in that the level is not as loud in this range, when using the K2 internal spkr.  I do not notice this "hole" nearly as much when using my Kenwood spkr.  I do not mean to knock my fine lil k2.  My Kenwood internal speaker is no better, only the external speaker is better.  Anyone else experience the "hole"?
 
Seems like it would be nice if Elecraft came out with a neat seperate speaker.  
 
Any one care to comment??
 
George, n4ym
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Ron D'Eau Claire-2]

George, N4YM asked:

...I understand the reason a lower pitch ST would be easier to copy when qrm
is present, due to the percentage difference matter.  My question concerns
what pitch is easier to copy when receiving fast cw when no qrm is present.
... Also, it seems my K2 pitch volumn has a "hole" around 550 to 625, in
that the level is not as loud in this range, when using the K2 internal
spkr....Anyone else experience the "hole"?

-----------------
What CW speeds are you thinking of George? My absolute maximum is about 40
wpm and that's head copy. I'm starting to work hard at 35wpm. 99% of my
"QRQ" CW is around 30 wpm and 99% of my general QSOs are between 15 and 20
wpm.

Those are very sedate speeds to real high speed (QRQ) operators.

Over those ranges the tone makes no different to me as far as the ability to
copy. I find the higher pitches (>600 Hz) tiring to listen to, so I usually
go for the lower frequencies. My K2 is set up for 500 Hz.

I almost always copy using phones. In the o-l-d days, especially in the
Army, I'd sometimes have to copy audio tones approaching 1 kHz on a
loudspeaker in the operating room. That was tough for me because the room
echoed, and echo got worse as the pitch frequency went up.

I assume you mean the sidetone pitch, not the volume, since maximum,
ear-splitting, volume occurs at 255 (mine is set to 11, Hi!). I don't notice
any unusual variation but level drops smoothly as the frequency goes up,
thanks to my having installed the sidetone improvement mod that makes the
non-sinusoidal tone a little less harsh. It's basically a low-pass filter so
it attenuates the higher frequencies. Still, the drop seems smooth on the
internal speaker.

Ron AC7AC

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[k6dgw]

[hidden email] wrote:
 > Anyone else experience the "hole"?

Yes, I have the same problem, I traced it to some body parts inside my
head (YMMV).  I have a fairly large hole in my hearing spectrum that
extends from about 700 Hz to light.  In fact most everything from 350 Hz
down to DC is also pretty punk.  Last audiology exam the VA gave me
showed a small but good looking peak in my organix response around 650
Hz, which is where I put my K2 sidetone.  As luck would have it, that is
close to the TS-850 sidetone as well, although it is seeing less and
less use now that I have the K2/100.

Seriously, I tried out your observation on my K2 with the QRP top on,
and my wife tells me it got distinctly weaker around 600 Hz ... I can't
really tell.  I tried stuffing the enclosure full of cotton balls (I
said "seriously," I really did do this), and it softened the character
of the "hole."  I guess I'd expect cotton to soften.  She couldn't hear
any real "hole" using the KPA100 speaker, but did say it didn't sound
quite as nice ... whatever that means to the audio engineers.

Since I use amplified headphones with the AF gain all the way up, the
speaker hole doesn't bother me.  Neither does the not-so-nice-sounding
KPA100 speaker.  Again, YMMV.

NEW SUBJ:  I finally figured out what to do to TR-Log to get it to talk
to the K2 (it involved reading the TR book, and then realizing I needed
to also turn the K2 serial port on in the menu ... I just love to solve
these really technical electronics problems), and I fear the TS-850 is
going get lonelier in contests now.

I'm still amazed by my radio, and, while I didn't design it, I did build it!

73,

Fred K6DGW
Auburn CA CM98lw
K2 #4398
KX1 #897
+various other Elecraft accessory toys.
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Sverre Holm-2]

> -----Original Message-----
>
> My question concerns what pitch is easier to copy
> when receiving fast cw when no qrm is present.  

There has been research on the topic of sidetone and level. It concluded
with 500 Hz and in some cases even lower tones to be favorable in noise free
environments.  This was published in Scandinavian Audiology, 1992, volume
pages 255-60:

Recognition of telegraphy signs at different listening levels and
frequencies.

by Montnemery P, Almqvist B, Harris S., Department of Audiology, University
Hospital, Lund, Sweden.

"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."

40 and 80 signs/minute should be 8 and 16 wpm. Peter Montnemery is SM7CMY
and a K2 owner, but I am not sure that he is active on this list any longer.


73

Sverre
LA3ZA
http://www.qslnet.de/la3za/
 

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Vic K2VCO]

Sverre Holm wrote:

> There has been research on the topic of sidetone and level. It concluded
> with 500 Hz and in some cases even lower tones to be favorable in noise free
> environments.  

<snip>

> 40 and 80 signs/minute should be 8 and 16 wpm. Peter Montnemery is SM7CMY
> and a K2 owner, but I am not sure that he is active on this list any longer.

I've heard it said that at 'super' speeds (65 wpm and above) a very high
pitch (like 1000 Hz) is necessary.  I suspect that the mechanism used
when copying at these speeds is somewhat different than that used at
lower speeds.  My feeling is that the operator recognizes words by the
combinations of buzz frequencies generated from the sharp rise/fall times.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com