[Elecraft] K-1 Sensitivity

[Ron D' Eau Claire]

> Most, if not all, of the rigs sold within the last 20 years are
> limited by the atmospheric and locally generated noise at a given
> location,
> not the receiver sensitivity.
> James R. Duffey KK6MC/5

Great point, James. But make that the last 80 years!

I've got tube-type regens that are limited only by antenna noise in my quiet
country location all the way up to 20 mHz or so, and I suspect that with
some additional effort on my part that upper frequency can be raised.

That is true even with quite narrow filters in the audio amp.

The stop-band attenuation in the filters and immunity from overload from
strong signals are the really big improvements in receivers that have been
made over the years. And getting those improvements has involved a constant
tradeoff between the spurious responses that are a part of any
superhetrodyne design and the filter and dynamic range that can be attained
with various filters, conversion schemes, etc.

Improved frequency stability and dial accuracy provided by modern
oscillators are also "nice", but don't help a modern receiver "hear" any
better than its tube-type ancestor.

What's fun about firing up an older receiver and listening around the bands
is realizing just how LITTLE improvement has actually been made in things
that affect most day-to-day operations in receiver design. That's not to say
that in a field day environment or when trying to pull a DX signal out of a
pileup, modern receivers like the K2 don't really show their stuff, but in
most routine operations there is really very little, if any, difference.

Unless you count the fact that the knobs on the newer rigs like the K2 are
so darn tiny that one can't hardly work them!

Ron AC7AC
K2 # 1289