[CW] Doesn't anyone know how to zero-beat anymore?

[Ken Brown]

Hi Ron,

I agree that it would be more spectrum efficient if more hams understood 
what zero beat is and also know how to do it. Discussions I have read on 
other reflectors indicate that many don't even understand the concept, 
and many of those who do don't know how to accomplish it
>  with todays rigs, it's a piece of cake to zero beat the other guy.
>   
I wish that were universally true. I must disagree with you that it is a 
piece of cake however. Some transceivers do have a sidetone frequency 
which is equal to the transmit frequency offset from a received signal 
which is tuned to zero beat AND have their IF filter band pass center 
frequency offset from the BFO by the same amount as the transmit 
frequency offset.

Both of those conditions have to exist in order to get your transmit 
signal zero beat to the signal of the station you are calling, by zero 
beating the received signal tone to your sidetone. (There are other 
methods, but if using this method, those conditions must be true)

Many rigs do not have that special relation between sidetone frequency 
and transmit offset frequency. Even when the sidetone is the "right 
frequency" (as described above) it often is so impure (not a pure sine 
wave, has lots of harmonic overtones) that it is difficult to zero beat 
the fundamental tone to the received tone.

Another problem is that many of those parameters are adjustable, either 
by front panel settings, settings in multi-layered menus, dip switches 
or back of the cabinet or inside the cabinet adjustment pots. So, even 
if the designers of the radio understood the concept and designed the 
radio to be able to zero beat easily, the user or previous user can have 
various settings changed so that the normal procedure no longer works. 
Some of the settings likely to get you lost, as far as zero beating 
goes, are sidetone frequency, RIT, XIT, IF shift or passband tuning, or 
BFO frequency adjustments.

Some rigs have some kind of indicator, like a LED, which you can use to 
get the received signal tuned just right. If all of the other variables 
are set right, when you get that LED lit up, your transmit signal will 
be zero beat to the received signal. It works great for R5 signals, I 
wonder how well it works with signals closer to the noise level. I 
personally would rather do it by sound than by a winking LED.

I recently had trouble in the Stew Perry Top Band Distance Challenge 
warm up session, at a friends QTH using a Yaesu FT-1000. Finally I 
determined what received tone resulted in stations hearing me, and it 
had no relation to the sidetone frequency that I could figure out.

It was easier when we mostly had separate transmitters and receivers. 
Using the spot function of the transmitter, to zero beat to the other 
station, listening with the receiver, was so simple and effective. As 
long as you did not get your TX on the opposite sideband, it worked 
every time.

I like the way my Ten-Tec Omni VI works. I know some rigs also have 
adjustable sidetone frequency, but do not make the transmit offset track 
the sidetone frequency.

DE N6KB
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