[Elecraft] Thanks re 817 & K2 audio

[George, W5YR]

Connect the K2 speaker or phones output to the input of your soundcard. Run
the SpectroGram program which is free - consult any search engine. Do not
connect an antenna to the K2. Look at the spectrum of the internal set
noise on the SpectroGram display. You will see the actual bandpass of the
combined Audio and IF sections of the receiver. Look at the effect of using
the different IF and AF filter settings. That will show you the overall
frequency response of the receiver.

If the frequency range is wide enough to provide the highs and lows that
you want to hear, the next issue is whether or not any part of the audio
system, including your speaker or headphones, is being driven into
distortion and at what level.

For this, nothing beats an oscilloscope with a steady modulated signal fed
into the antenna. In a pinch, use WWV. Set the AF Gain for your normal
listening level. Go through the audio system with the scope and look for
any evidence of overdriving or flat-topping of waveforms. If that is clean,
chances are you radio will sound pretty good. If it still doesn't, then
investigate using another set of phones and/or another speaker.

Audio "quality" is part engineering - frequency response, power level
without distortion, etc. - and part psychological: your notion of what it
"should" sound like. You can measure the first, but only your ears can do
the second part.

Tim, if it sounds as good as the PRO, leave it alone!   <:} I can send you
spectra of one K2 in all modes and filters if you would like to see them
and can take a large download of .jpg files.

73/72/oo, George W5YR - the Yellow Rose of Texas         
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe   
Amateur Radio W5YR, in the 56th year and it just keeps getting better!
QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735
Icom IC-756PRO #02121  Kachina 505 DSP  #91900556  Icom IC-765 #02437


Tim and Nancy Logan wrote:
> 
> Wayne, Tom, et al -
> 
> Thanks for feedback on the K2 and 817 audio question. Your comments
> clarify things for me, but give rise to another question. If I wanted to
> compare MY K2 audio to the the audio produced by a perfectly built K2
> (ie let's say Gary built it), what would be used as a baseline
> comparison? How do you compare audio output from one rig to another? How
> would a builder be able to confirm for himself that the audio output
> matched with the disigner's intended audio output? How can it be
> measured in our simple "home labs"?  Kind of an interesting question to
> me?     Thanks for the help guys. 73/Tim NZ7C