Topband: dsp afterthought

[Doug Waller]

> Food for thought:  Could we develop a pre-receiver front-end, which
> incorporates a noise amp, delay line, and noise gate, which could
> be shaped to respond to lightning-type non-repetitive impulses.

This kind of thinking gets me going!  From my layman point of view, could we
utilize a high speed dsp discriminator circuit to identify ANY signal that
is over a user-selectable level, then re-insert that signal 180 degrees out
of phase back in line at the proper level to either null the signal, or
reduce its level to the same as that of the weakest desired signal?  This
would be great for contests, as well as weak DX in the noise.

With reference to the notion of lightning being one long broadband crash
signal, I offer the following.  Several years ago the Transmission &
protection engineer at UTF handed me an old brown book.  It was a lightning
study commissioned by NASA in Titusville, FL years ago.  One thing I
remember is that they used super high-speed cameras to determine that all
lightning strokes were really several hundred individual strokes happening
within a fraction of a second.

If this is really the case, are we not back to looking squarely in the face
of a modified or re-designed NB or DSP that could easily remove each
individual pulse signal ?  With all the collective wisdom we are blessed
with on this reflector, I look forward to some BIG breakthroughs in the near
future.

Hope to meet many of you at this year's Dayton Topband Dinner.

73, Doug / NX4D  (nr Orlando, FLa)