[TenTec] Zero Beat

[Tom Rauch]

> 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