[Elecraft] Tuning - CW and CW Reverse?

[Ron D'Eau Claire]

I'll second Tom's comments about "zerobeating" with a couple of
observations...

First, it is IMPORTANT to have the two tones close to the same loudness!
If your sidetone or the signal are much louder or weaker than the other,
the "beat" will be VERY HARD to hear!  Practice on WWV and you'll see
what I mean. 

And, just like that first ding in a new car, once you "see" it you'll
spot the beat quickly and easily ever after, whether you want to or not.


Secondly, be aware that us OT's had is GOOD when it came to learning to
"zero beat". With receivers that could be "broad as a barn" and no
filters to cut off one sideband (f there was one, it was out of the
circuit most of the time), tuning across a signal meant that you heard a
very high-pitched "beat note" than dropped steadily lower as you
approached it until it did go to Zero Hz! Then, as you kept tuning it
appeared again on the "other side" and increased in pitch until it went
out of the bandpass (I'm talking pre-1950 technology here...). 

To put our transmitters on someone's frequency, we just flipped off the
receiver BFO (yes, they used to have a switch. The BO had to be off to
receive AM Phone!), flipped ON the transmitter VFO to produce a
low-level spotting signal, and tuned the VFO until we heard it beat
against the signal. We tuned the transmitter VFO until the beat went to
zero and we knew that we were sitting right on the other station's
frequency. Zero really meant ZERO. No tone at all! Maybe some thumps
from the keyed signal, but that was all. 

But pretty quickly we learned that we could do it with the BFO ON. Then
we'd still hear the beat like you do in the K2. What you are listening
for is the beat between the audio tone produced in the K2 as the "Spot"
frequency and the beat produced between the signal and the K2's BFO.
When they get close, you will hear all three notes: the SPOT tone, the
tone of the BFO beating against the signal, and the "beat" between the
two audio signals what you want to set to "zero". 

That's why it's so important to have them at the same level. That makes
the third "beat" that you want to set to zero as loud as possible, and
it will be very easy to hear once you do that and tune slowly across the
signal. It does not require any "tone sense" at all. You can be
completely "tone deaf" and it won't bother your accuracy. 

We can set signals much closer to zero beat in the K2 than we could
tuning for "zero Hz" with our old separate transmitters and receivers.
That's because good receivers suppress audio frequencies below about 200
Hz, so it was very hard to hear anything down near zero. The K2 does
that too, but now you are listening for tones at the sidetone frequency,
and the beat modulates them, making them swing up and down in loudness
with the "beat" when you are very close. 

You can set them to within 10 Hz easily with the K2. We were lucky to be
within 100 Hz or so tuning for "zero" Hz with our old gear. But, then,
no one expected to be closer than a few hundred Hz anyway! And if you
stayed within a few hundred Hz during the QSO, the rig was exceptionally
stable! <G>

Ron AC7AC
K2 # 1289