If you happen to have a rig with a CW-R or CW reverse button, you can push
that button and if you are tuned properly, the pitch will not change. That's
how I usually get within 10hz. After doing that a few times, your ear gets
used to the proper pitch to tune for. All of this assumes that your
oscillators are properly aligned.
Steve Ellington
N4LQ
When two wrongs don't make a right, try three.
----- Original Message -----
From: "Tom Rauch" <w8ji@contesting.com>
To: <TenTec@contesting.com>; <telegrapher@earthlink.net>
Sent: Sunday, March 10, 2002 7:24 AM
Subject: Re: [TenTec] Zero Beat
> > Using computer software works great for zero beating. But it would be
> > nice to have something visual in the radio itself. Although, I am not
> > tone deaf - some are. I just prefer the quicker visual spotting.
>
> Even when tone-deaf, you can still zero beat signals. You might
> have to "hunt" for the beat a tiny bit more, but it is no problem to
> find. Like many skills, a little learning and practice will offset lack of
> natural ability to match two tones with hearing them both at the
> same time. The "tone-deaf" user simply has to listen for and focus
> on the naturally occurring beat between the two tones.
>
> I never ever use the CW TUNE light in my FT1000D, I consider
> another one of those unnecessary "features" that blinks away to
> make a radio face "look busy".
>
> By far most of the problems with zero-beating relate to the
> transmitter not being centered at the same pitch as the receiver.
>
> On CW, if you listen to normal lower pitches (most CW ops I know
> actually prefer 400-600Hz tones) there are radios where it is
> necessary to order a special low-pitch CW filter and/or offset
> passband tuning! You have no way to actually move the carrier
> offset in the filters.
>
> Such systems are very poor, but they are probably used because
> the radio was designed with SSB in mind where passband tuning
> MUST be done with a constant carrier frequency. On SSB,
> everyone **wants** the same pitch, they just want a different
> passband.
>
> If you carry that system over to CW, the receiver works poorly. You
> have to offset filters while the "carrier oscillator frequency" remains
> fixed at the design value, which is almost always too high for
> serious CW work. (Who the heck ever picked 1000 Hz, when the
> middle of the music scale is 440 Hz?)
>
> That should NEVER be done, because it guarantees the TX will be
> off from the RX frequency when they share a common oscillator
> system.
>
> CW receivers need a carrier oscillator shift to control pitch, not a
> passband or filter shift! The beat detection system is a distant
> second to proper pitch selection systems.
>
>
>
> 73, Tom W8JI
> W8JI@contesting.com
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
|