Jim is entirely correct although we will disagree a bit about the need to keep the line out as low as he suggests. My own measurements say the harmonic distortion is insignificant as long as the Line Out levels stay below .5V RMS.
The headphone outputs are exceptionally clean as long as the audio amplifier level is kept below 2V peak (1.4V RMS) and the output impedance is not too low. In fact, noise in the audio amplifier (headphones) is 70 dB below the desired (CW at 500 Hz) signal +/- 250 Hz and 80 dB below the desired signal above that. All harmonics are down more than 60 dB as long as the headphone level is not at levels that could damage hearing (> 1.4V RMS). The headphone output in the K3 is cleaner than any amateur receiver I have seen and certainly better than the current crop from Ikensu or Yaecomwood. > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Jim Brown > Sent: Monday, September 01, 2008 12:06 PM > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] K3 Harmonic Distortion > > > On Mon, 01 Sep 2008 14:30:45 +0100, Berni G0IDA wrote: > > >I hope there is a cure for this as it's frustrating listening to CW > >with this sort of distortion. > > There are three things you should do. > > 1) Make sure that the AGC is on, and that the CONFIG AGC > settings are at the defaults. > > 2) Reduce the LINEOUT GAIN (on the CONFIG menu) to a value > less than about 4. This prevents distortion that could occur > in the output transformer. > > 3) Adjust the input gain of your computer so that you have > enough signal for the decoder to function, but not enough > to cause distortion. > > This should correct any problems. > > 73, > > Jim K9YC > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
