This is all true but in the TT rigs prior to PBT, there was no such noise.
Sit a Triton IV next to an Omni V, Connect both to an antenna and tune to
20 meters where there are no stations. Crank up the volume. On the Omni V,
you will hear a mighty roar which will vary in pitch with the PBT
adjustment. On the Triton you may hear a faint rushing sound and a tiny
audio hiss. So for the most part, the PBT induces a problem then allows us
to compensate for it with it's own control. Oh sure, you can leave your
filter set for 2.4khz and move the passband to reduce qrm but you could
have done the same thing with a more narrow filter anyway. At first, PBT
seems really cool and impressive but the trade off is the addition of
another noise source, oscillator, mixer, I.F. amplifier etc. I've found
that listening to the older pre-PBT rigs is much easier on my little
brain.
PBT like BEANS adds lots of energy but lots of noise. 73
>
> In other words, if you have the 250 Hz filter and your normal sidetone/CW
> frequency is 600 Hz, tune a signal to 600 Hz pitch by matching it to the CW
> sidetone. Then rotate the PBT so the noise appears to lower in pitch, and
> do it until the signal just disappears. Then back off the PBT until the
> signal just reappears again. Hear the difference? You can also set the
> noise higher in pitch than the signal, but I think most people would prefer
> it lower.
> --
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>
>
Steve Ellington N4LQ
N4LQ@IGLOU.COM
--
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