[Elecraft] K2 S/N 4787 First QSO

[Jim Harris]

Thanks Ron,

You've gave me some good information.  Now I remember
the filter and processor settings.  I'll have to go
tweak them and see what we get.  

I'm hoping the 12 uhenry inductor will give more range
and will help stablize the frequency.  Support also
stated they had gotten some crystals that were not
"rubber" enough and recommended replacing the
associated inductor.

I'm going to print your response and put it with my K2
fact folder.  

Thanks again,

Jim, AB0UK
--- Ron D'Eau Claire <rondec at easystreet.com> wrote:
> 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
> 
> 
> 
> 


		
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