[Elecraft] K2 Phase noise etc.

[Ron D'Eau Claire]

Mick, M1MGD wrote:

...please take time here to think that most of the top range black box
tranceivers that are on the market today probably have more money spent on
their sheilding and imunity to strong interferance than the total cost of
the K2 plus a few  options.

------------------

I hope they keep at it. Here's why.

My K2/100 S/N 1289 is going on five years old now, and the thread on phase
noise reminds of several others that went on and on and on and... 

One was about the lousy reception on SSB one sideband, even with the SSB
adapter installed. That led to a discovery that the 2nd XFIL at the i.f.
output had a passband tilt that made some bands sound bassy and others with
exceptionally bright highs. The 2nd XFIL mod came of that and it became a
basic part of the design at S/N 3000. 

Then there were those ops plagued by noisy audio pots which turned out not
to be a problem with the pot at all but the way it was used in the circuit.
Long ago that was changed. 

And almost immediately there was a long discussion about ripple and the
bandwidth of the OPT1 filter on the SSB board that at first was written off
as a bunch of overly-picky ops until Wayne & Eric discovered that the spex
they had on the crystals being sent out with the kits weren't tight enough.
Some SSB filters had bandwidths as low as 1.8 kHz - way too "tight" for
decent audio no matter how the BFO was adjusted. Those of us whose filters
didn't meet specs got, gratis, a whole new set of crystals. Other ops who
weren't experiencing problems were offered new crystals if they wanted them
at a nominal price. And John Grebenkemper produced some alternate OPT1
filter setups using various mixes of capacitors to provide builders with a
selection of filters bandwidths and lower passband ripple! 

Somewhere along the way someone noticed a "howl" in their K2 when strong
signals were present - as in a multi-op field day environment. That also
produced a long thread that resulted in the addition of two diodes to the
i.f. amplifier to keep it stable no matter how much RF hits it from nearby
rigs. 

I could go on and on with many more such improvements to the K2, almost
every one of which seemed some esoteric unsolvable issue affecting only a
few ops at first. These are enough, I hope, to make the point that we never
know what is involved in making an improvement until someone figures it out.
One of the biggest "features" in the K2 - in all of the Elecraft rigs - is
Elecraft's support of those who want to dig in and tinker and try
improvements. 

I consider that a huge improvement over the other manufacturers who can only
advise ops who notice a deficiency in their rig to dump it at the next
Hamfest and trade up to the latest super-mega-whopper box at twice the price
because, perhaps, just perhaps, that problem was fixed in the last
redesign... 

I find this subject very interesting, and I hope the ops working the problem
keep posting on the reflector for all of us.

Ron AC7AC