[Elecraft] Zero beat

[Don Wilhelm]

  Ron,

You are quite correct, but it is not all hearing loss, it is a case of 
tone perception, and some of us are "tone-deaf" even without hearing 
loss.  Many suffer from "tone-deaf" problems.  I used to break guitar 
strings because I could not determine if I should tune it higher or 
lower - I finally bought a device that helped a lot with that problem - 
it got close, but not exact - once the tones were close enough that I 
could discern the beat note, there was no problem in getting the guitar 
tuned properly.

Now for those of us with tone discernment problems like mine, when the 
two tones are close, we can hear the low frequency "wow-wow" beat with 
no problem - the real problem is getting the two tones close enough to 
hear the "wow-wow".  Fortunately, the K3 has the CWT indicator which is 
a big help to me.

73,
Don W3FPR

On 2/1/2011 9:16 PM, Ron D'Eau Claire wrote:
> You may be quite right, Tom. Many of us have various levels of hearing loss.
>
> However, the "red flag" that causes people to say things like that is the
> use of the phrase "matching tones".
> There is *no* "matching tones" in the process of zero beating, which gives
> the impression the person is trying to do the wrong thing!
>
> We don't care what frequency the "tones" we're hearing are. We are listening
> for the third tone that disappears when "zero beat" is achieved. So it's
> only a matter of hearing whether a tone is there or not.
>
> It WAS easier in the "old days" because there was only one tone and we tuned
> until it disappeared completely. Nowadays we have three tones, only one of
> which disappears at 'zero beat'.
>
> Having the other two tones, whatever frequency they might be, at the *same*
> level makes the third tone as loud as possible so it's easier to hear when
> it disappears.
>
> Having followed this thread many times over the past decade, I'm becoming
> convinced that some people have a very hard time hearing more than one tone
> at a time. Even minor QRM on a CW signal stops them cold unless they can
> filter it out in the receiver. For such people hearing the third tone is
> probably very difficult or impossible.
>
> Many of us OTs have for years used very broad receivers on CW and learned
> long ago to listen to several signals at once, picking out the one we want
> to copy just as one picks out one conversation out of many in a crowded
> room. Perhaps what we're seeing today is a side effect of modern receivers
> where listening through real QRM is almost unknown.
>
> 73,
>
> Ron AC7AC
>