Re: [TenTec] CW Tuning with Omni 6 Plus

["DAVID HELLER" <dtx@verizon.net>]

Like so many other physical phenomena, the effect of zero beating is so 
difficult to express in words, but with several simple vector diagrams the 
whole situation becomes obvious.
----- Original Message ----- 
From: "Duane Calvin" <ac5aa1@gmail.com>
To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Sent: Friday, June 01, 2007 9:16 PM
Subject: Re: [TenTec] CW Tuning with Omni 6 Plus


> Exactly - zero beat is when the "beat note" between the two tones goes to
> zero Hertz.  Hence, zero beat.  Musicians know all about this when they 
> tune
> their instruments.
>
>  73,  Duane
>
> Duane Calvin, AC5AA
> Austin, Texas
> www.ac5aa.com
>
> -----Original Message-----
> From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
> On Behalf Of Ken Brown
> Sent: Friday, June 01, 2007 6:20 PM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] CW Tuning with Omni 6 Plus
>
> When two tones (RF or audio) are at exactly the same frequency, they are
> "zero beat" with each other. They could be at any phase relation to each
> other, so the amplitude of the sum of the two could be anywhere from
> twice that of one of them or zero. Without careful amplitude adjustment,
> the two tones will not be equal, so twice the amplitude, or zero, will
> seldom occur. Even with careful amplitude adjustment the phase relation
> will seldom be exactly zero or 180 degrees, so double amplitude or zero
> amplitude sums will still be rare.
>
> Having said all of that, the sum is just as likely to be lower amplitude
> as it is to be higher than that of either single tone.
>
> James Duffer wrote:
> > snip
> >
> > >     When the "cw" button is pushed you get a sidetone. While holding 
> > > down
> > > this button you move your dial until your target's tone is "beating"
> > > against your sidetone. When you move the dial enough so that your
> sidetone
> > > no longer "beats" and the tones are "insync" they become "one". When two
> > > tones become "one" the tone gets louder. This is "zero beat". Even 
> > > having
> > > just "beating" is close enough for govt work.
> > snip
> >
> > For many years I have been under the impression that "zero beating" was
> the
> > method of beating (hetrodyning) of two frequencies bringing their
> difference
> > down to the audible range and adjusting one to match the frequency of the
> > other so that the two tones beat against each other producing "zero" out.
> > Thus the term zero beat.  Not a louder tone.
> >
> > de wd4air
> >
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