Topband: Pulse response

[Tom Rauch]

> a preamp increases the width of narrow (short-duration) pulses such as
> those we hear from lightning discharges, the receiver may be
> effectively disabled for the duration of the pulse.  I injected 20
> nS-wide, positive-going pulses and looked at the preamp

I don't think this is a valid worry.

The duration of a lightning discharge is relatively long, in the order of
hundreds of milliseconds to a few seconds.

Even if the pulse were very short and abrupt, the receiver's selective
circuits and AGC system would absolutely overshadow any problem in a
preamplifier making it totally unnoticeable. When we have a receiver with
.25 to 3kHz selectivity stages and multiple stages, it dominates both
ringing and distortion in the system.

The worse effect of a preamp would be it could (in some cases) add
unnecessary gain, causing circuits in the receiver to overload needlessly or
to become excessively dependent on AGC.

73 Tom