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Author Topic: Questions about CW pitch  (Read 7846 times)
SV2HTC
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« on: December 15, 2010, 05:43:08 AM »

Hello there to all. I've been in the superb mode of CW for some (small) time and a couple of questions aroused about CW pitch. Would a different pitch affect what the other operator of the CW QSO hear or is it just a matter of personal preference in what would I like to hear through my headphones when I TX? Secondly if I try to zerobeat a station with a different CW pitch (let's say I' m using 700Hz whereas his is 500Hz), do I have to do something differently? I am using the CW spot feature of my Yaesu and rotation of CW-CWR in order to be sure of the procedure. TNX U in advance for any replies, DE Jim SV2HTC, GREECE.
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VA7CPC
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« Reply #1 on: December 15, 2010, 08:25:21 AM »

If you use a spot tone generated by your own transceiver to "zero-beat" the other signal (that is, you match the received tone to your "spot" tone), you will be "zero-beat" _regardless of differences in CW Pitch_ between you and the sender.

Your transceiver doesn't know, and doesn't care, what _his_ CW Pitch is.   It doesn't have to.   He's transmitting on frequency X; your "spot tone" is generated (conceptually) on your transmitting frequency (whatever the dial says, in any recent transceiver).   When your "spot tone" matches your received audio tone, you're tuned to the same frequency he is using.


                      Charles
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SV2HTC
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« Reply #2 on: December 16, 2010, 05:10:10 AM »

TNX Smiley
Would a low in Hz pitch be better in going through noisy conditions?
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KB7QOA
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« Reply #3 on: December 16, 2010, 01:31:29 PM »

It is all personal preference.  If it is easier for you to pick out a low tone when you have lots of noise, then set your rig to the tone that is comfortable to you.  As long as you tune until your transceiver spot tone is the same as the signal you are hearing, you are properly tuned.  Your signal will be at the pitch preferred by the person on the other end of the transmission.

The tone you hear from your transceiver makes no difference in the transmitted signal.

Hope that helps!

Jeremy
KB7QOA
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VA7CPC
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« Reply #4 on: December 16, 2010, 05:38:20 PM »

TNX Smiley
Would a low in Hz pitch be better in going through noisy conditions?

ON4UN, in "Low-Band DXing", suggests that low pitches _are_ better.  [See Chapter 2, section 7, "Zero Beat"].

The logic works like this:

Quote
The ability of the ear to discriminate signals very close in frequency is best at lower frequencies.  For example, listen to a signal with a beat note of 1000 Hz.  Assume a second signal of very similar signal strength and keying characteristics starts transmitting 50 Hz off frequency (at a 950 Hz or 1050-Hz beat note.  Separating those two signals with IF or audio filters would be very difficult.  Let us assume we have to rely on the "filters" in our ears to do the discrimination.  The relative frequency difference is:

( (1050-1000) / 1000 ) * 100 = 5%

If your were using a 400 Hz beat note, the offender would have been at 450 Hz (or 350 Hz), which is a 13% relative frequency difference.  This is much more easily discernible to the ear.

He also says that the choice of beat note is a very personal preference.

                     Charles
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KS2G
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« Reply #5 on: December 16, 2010, 07:12:41 PM »

As I believe VA7CPC was trying to explain...

A cw signal has no "pitch".

It's an un-modulated (continuous wave) rf carrier.

If you tune to it exactly with an AM detector, you won't hear anything.

The "pitch" (tone you hear) is a product of your receiver.

Back in the day, a BFO (beat frequency oscillator) in your receiver provided the tone you heard -- and usually included a control for varying the audio frequency ("pitch") of that tone to your liking.

In current rigs, there's a similar circuit that provides the audio tone -- usually set-up such that if you tune to exactly the frequency of the cw signal ("zero beat") you'll hear a tone that's the same pitch as your cw "side-tone" -- the tone you hear when you transmit cw.

You can vary that tone --higher or lower-- by tuning-in the cw signal either slightly higher or lower than zero-beat.

And as others have stated, how well you hear a tone of any particular frequency ("pitch") is a matter of personal preference.











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WO7R
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« Reply #6 on: December 16, 2010, 10:38:13 PM »

What KS2G said.

In addition, consult your own ears.  As we age, we start to lose the ability to hear certain pitches (this varies by the individual, though IIRC higher pitches _usually_ go first).  And, maybe you have other problems like ringing in the ears.

Any of that could matter more than the theory.

That said, I do follow ON4UN's advice and use a lower tone than is typical.  But, my hearing has always been excellent.
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K1BXI
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« Reply #7 on: December 17, 2010, 08:31:13 AM »

All good advice above........I would add that a good pair of headphones makes copy much better than from using a speaker......then again, you may have found that out all ready.

John
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SV2HTC
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« Reply #8 on: December 17, 2010, 03:08:25 PM »

Tnx all for lightning this! --... ...--  Grin
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W0BTU
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« Reply #9 on: December 19, 2010, 07:17:17 PM »

... Would a low in Hz pitch be better in going through noisy conditions? ...

I fully, 100.00%, agree with ON4UN. The lower the better, based on the limitations of the receiver.

And it's less fatiguing listening to a lower note.
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KT1F
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« Reply #10 on: December 20, 2010, 06:33:03 AM »

If you prefer an audio tone that is different to what your transceiver is setup for, then you will tend to be off frequency when you answer someone.

My old TS430S is setup for 800 Hz. It's not programmable so I can't change it. If I prefer 600 Hz and tend to tune for it which is well within the bandpass of the wider filter then I'll be answering someone 200 Hz off frequency which will cause the tone at the receiver end to shift by 200 Hz. That's probably not enough to be a problem but something to be aware of. It might cause the other station to tweak his RIT to get the tone that he prefers.
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W0BTU
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« Reply #11 on: December 20, 2010, 04:26:24 PM »

If you prefer an audio tone that is different to what your transceiver is setup for, then you will tend to be off frequency when you answer someone. ...

That is a good point that ought to be discussed here, but it doesn't have to happen. It depends on your equipment, and how you use it.

Often, I make sure I'm on the same frequency as the calling station by listening to both my signal and his on a separate receiver.
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WD6GLA
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« Reply #12 on: December 21, 2010, 11:07:04 PM »

I envy you guys with acute hearing .   Mine has seen better days  due to old age and years of working in noisey environments ,   so I have to adjust to whatever suits my frequency range the best .     Right now I set my sidetone to  about 600 and it works for me .   Ditto on the headphones ..... they really help pulling those weak ones out . 

And protect your hearing !   Use hearing protectors or earplugs when you are working in a noisy environment !  You'll be happy you did when you get older !

Bob Tadlock 
N7BDY
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K5RIX
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« Reply #13 on: December 31, 2010, 09:58:09 AM »

Lots of good advice on this thread.  It's really important to understand how to be on the other station's frequency.  If your rig is such that the sidetone pitch isn't adjustable and/or doesn't track the "offset", you will need to learn that pitch.  There are many ways to do this.  It's pretty easy for most people to remember the music pitch (in our Western convention) A=440Hz.  The audio frequency of other pitches can be deduced 1/2 step at a time using the multiplier (1 divided by the twelfth root of .5).  This number is roughly 1.059.  So A 440Hz X 1.059 = 466Hz or B-flat; 466Hz X 1.059 = 494Hz or B, etc.  I am aware this music theory-approach to pitch determination can be awkward, but once done, it makes more sense!

For example, I have a Ten-Tec Argo 556 QRP transceiver that has a fixed CW offset of 750Hz which is also the side tone pitch frequency.  I can either match the side tone pitch to the received signal's pitch, or I can determine the closest music note to 750Hz and use that to get very close without transmitting.  Going through the arithmetic iterations, 750Hz is very close to f#.  So I can adjust the receive frequency pitch to f# and be very close to the sending station's frequency on my '556.

Most newer transceivers allow adjustment of the CW offset pitch, and the side tone follows along.  In this case, simply match the side tone pitch (or "SPOT" pitch if the rig is so equipped) to the received signal pitch.

It is very important to be cognizant of your side tone pitch in relation to the frequency of the station with which you wish to communicate.  Along that line, always remember to turn off the receiver RIT when not actually using it.  I hope this isn't too confusing!

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W5LZ
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« Reply #14 on: January 02, 2011, 06:52:25 AM »

This applies to the 'personal preference' part of pitch.
I've found that my personal preference of pitch has changed over the years.  I think that's because my ears/hearing has changed.  I used to like a mid to higher pitch, it was good for me.  But that pitch has 'lowered', a loss of hearing on the higher frequencies. 
I've also found that if I/you have problems hearing a 'nice' sounding pitch, then pick one that sounds terrible but that you can hear.  It does improve copying.  There's two sides to that good/bad pitch thingy!
Paul / W5LZ
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