[Elecraft] Re:New Crystals or Not

[Paul Jensen]

> OK.  So I'm somewhat confused.  Some with "early" crystals are AOK, while
> others have K2's with apparent problems.
>
> Is there a definitive, non-subjective test that can be conducted to verify
> the performance of the crystal filter to determine if replacement is
> warranted?  I'm looking for something more concrete than reports of "poor
> transmit audio" or other qualitative judgement...

IMHO, some test of total receiver gain is really needed.  This would show
if the crystals are a matched set.  A poorly matched crystal set would
have low receiver gain.  The spectragram just shows the filter shape, not
the absolute gain of the receiver.

A simple test might be have a small pc board with a calibrated 1 microvolt
rf signal hooked up to the K2 antenna input.  Turn AGC off, set rf gain to
max, and set volume control to a specific resistance.  The voltage on the
speaker measured with a DVM could be used to calculate the total gain for the
receiver.

Perhaps this rf signal board could be a kit like the noise generator
board :)  Then we could all post our results and see if our K2 is up to snuff.

Paul Jensen
AD5IW