[Elecraft] K2 S/N 4787 First QSO

[Ron D'Eau Claire]

Jim, AB0UK wrote:

Got the SSB and NB installed and decided it was time
for that first QSO.  A friend across town was happy to
oblige.  He was impressed with the audio.  He recorded
it and it sounds nice when played back.  Received
audio sounds a little tinny....maybe it is just my
headphones and the tiny speaker. 
---------------------

With my K2 set for optimum xmit audio, I find the receive audio tends to cut
off more of the "lows" than I like on some signals. The ideal bandpass
definitely changes with the voice on the other end. So I have FL2 set using
the OPT1 filter for a BFO frequency that shifts the bandpass slightly to
produce more bass in the signal (bandpass closer to the carrier freq). That
gives me way to shift the tone of the received signal by changing filters.
The settings for FL1 are *always* used for xmit, no matter what filter
position you are using for receive, so adjusting the other filter positions
to suit your taste will not have any affect on your transmit audio. 

Jim wrote:
During the qso I
realized that either there is no mike gain adjust or
it's buried in a menu that I can't remember.  Anyone
know where that might be? 
--------------------

Mic gain is set via an attenuator and then automatically adjusted in the
speech processor I.C. The mic attenuator control is available under MENU
option SSBA. SSBA 1 attenuates the audio by 10 dB. SSB 2 or 3 provides full
gain with no attenuation. 

Jim wrote:

I've realigned the 4 mhz and PLL three times against
WWV and my friend says I am still 20-30 hz off.  Does
it settle down at some point or do I need to chase it
every few days?

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

One of the features that gives the K2 receiver its 'edge' in hearing weak
signals over many of the other rigs is that the K2 does *not* use a
fully-synthesized local oscillator. With that superior receive performance
comes a trade-off: the K2 simply is not as stable as those other rigs with
fully-synthesized L.O.s in crystal ovens. Still, current K2's are very, very
good, but it deserves a good 15-minute warm-up. 

One other issue that affects your frequency readout is the ability of the K2
to reset the oscillators to a specific frequency. When you calibrate your
K2, the analog voltages used to tune the oscillators are converted into
digital values and stored as digital data in memory. When you tune in a
specific frequency, the logic looks up those digital values and converts
them back into the proper analog tuning voltages. This conversion back and
forth is done by "Digital to Analog Converters" or DACs. DACs have a
specific amount of accuracy. More accuracy requires bigger numbers and more
memory. The tradeoff that Elecraft used between memory and accuracy puts the
K2 within about 20 or 30 Hz of the expected frequency.

That said, one might ask how accurate the other guy's rig is. A quick check
for you is to tune in WWV. Give your K2 a 15 minute warm-up at least, then
zero beat WWV's carrier and check your K2's frequency display. I just turned
on my K2 a few minutes ago and it's showing WWV at 10000.01 kHz right now -
10 Hz high. 

Ron AC7AC