[Elecraft] On zero beating

Fri Jan 18 13:00:11 2002

Fellas:

You don't have to be able to hear the 'beat' (or to dance to the music... 
but then I digress...) if you can merely tune the received signal such that 
it 'disappears' WITHIN  the sidetone. As you tune the received signal thru 
the sidetone, there will be a point at which they will merge and be one... 
you'll hear the sidetone just as before, but you will note that the 
received signal just makes the sidetone appear to be slightly louder during 
the moments when the received signal is present. THIS is akin to being ZERO 
BEAT by other methods... and is often much easier to achieve than actually 
trying to HEAR the beat note (mathematical difference between the received 
tone and the sidetone).

73 - Tom Hammond   N0SS

At 02:45 PM 1/17/02, you wrote:
>Tim,
>I too have found this difficult to hear with a discontinuous CW signal.
>The "beat" is produced by the difference in the two audio frequencies: the
>spot tone and the apparent tone of the CW signal.  The beat frequency goes
>down as the differences are minimized further, until the beat is zero --
>indicating perfect match in frequency.  The ear hears a subtle
>Wah...wah...wah...wah which is the beat note indicating the frequencies
>are not quite matched.  A slight change in the tuning dial, increases or
>decreases  the period of the beat note or the separation of the
>wah.......wah......wah......  The desire is to decrease the beat resulting
>in matched frequencies.
>
>This is easy for me to hear when tuning my guitar, and I suspect a violin
>to be much the same.  Here the tones are long and continuous.  But the
>key, as you well point out, is two continuous tones -- not the case in
>spotting a CW signal.  So, like you, I struggle on the non-continuous
>signal.
>
>Perhaps the "ultimate" spotting tool would be to measure the audio
>frequency of a received CW signal and display it -- perhaps at the touch
>of a button.  Knowing your sidetone is set to, say 700Hz, you could then
>adjust the dial frequency so the received CW signal is also at 700 Hz.
>Since the K2 has a frequency counter logic, perhaps this feature could be
>implemented?
>
>Steve
>aa8af
>
>
>
>
>
>
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>
>[email protected]
>Sent by: [email protected]
>01/17/2002 03:04 PM
>
>
>         To:     Elecraft Reflector <[email protected]>
>         cc:
>         Subject:        [Elecraft] On zero beating
>
>
>Hi folks -
>
>Although it may be clear as a bell to most people, I thought I would share
>my
>experinces as a beginner with zero beating. It may be of interest to
>newcomers
>in HAM.
>
>Every text I've read seems to define zero beat by referring to the word
>"beat".
>I never HEARD any "beat". What the heck was everyone talking about! I
>never new
>what that "beat" was and finally got too embarassed to ask people anymore
>about
>it.
>
>In the mean time I would tune in on a signal by simply using SPOT and
>matching
>the tone by ear. Since I play the violin, this is very easy for me. On the
>other
>hand, my Code Buddy from FISTS finds that type of thing almost impossible.
>The other way I tune is simply to get the signal as loud as I can in the
>narrowest filter setting. With my K1 and K2 that seems to always be just
>about
>dead on.
>
>For you fellow beginners, I was FINALLY enlightened when installing the AF
>
>filter the other nite. The manual said to zero beat the CONTINUOUS tone at
>
>7000.00. MAGICALLY WHEN THERE IS A CONTINUOUS TONE ZERO THE DEFINITION OF
>BEAT
>BECOMES TOTALLY OBVIOUS. As soon as you are dead on the two tones sound as
>if
>they are one tone which has a rhythmic rise and fall of the tone. This
>rise of
>the tone is the beat. When you listen to code being sent, you do not have
>a
>CONTINUOUS wave - so you seldom have the signal coming in long enough to
>hear
>this illusive beat!!!! Key word here: continuous :-)
>
>I guess what I am trying to share is what the word BEAT really refers to
>if you
>were confused like me. Also, once I heard what the beat was on the
>contiuous
>wave, it helped me with matching the SPOT even more - you may not hear the
>beat
>per se when receiving code, but you can hear when it's getting right in
>the
>groove. Perhaps listening to really fast ops sends such a rapid signal
>that you
>hear even more of a beat.
>
>Anyway, I found this simple thing to be a true revelation. If it's
>confused you
>- go down to 7000 without the antenna etc etc and you will be able to
>learn the
>true basis of the word BEAT.
>
>Sorry to bore you experienced folks with this simplicity!! If I've said
>anything
>that needs correction or the voice of experience - please jump in so I
>don't
>mislead anyone!
>
>73/KB7OEX Tim Logan
>
>
>
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