On 4/14/2013 12:15 PM, Don Wilhelm wrote:
I suggest you reduce the soundcard gain to the range of 1/2 to 2/3 of full which will allow more range on the SignaLink gain.
YES! Several times I've published a simple procedure for setting computer sound card levels. It goes like this.
1) Find "cliip level" on the sound card. To do this, feed the sound card output to a scope, get your RTTY or PSK program going, and push the buttons that cause it to send tones to the radio. On the scope, gradually increase the sound card output slider until you see squaring at the top and bottom of the sine wave.
If you don't have a scope handy, listen on headphones as you gradually increase the level until you hear the tones get "raspy" or "harsh" or "brighter." With an AC voltmeter, look for the point when the reading no longer increases as you increase the slider. Of these three methods, the scope is best, your ears and headphones are second best. Use the voltmeter method only if your hearing is gone and you don't have a scope.
2) Now that you've established "clip level," back off the slider by 6 -10 dB. 6 dB is half the voltage, 10 dB is about one-third the voltage, easy to see on a scope or voltmeter. If you're using your ears, back off the slider until it SOUNDS "half as loud." This works because human hearing is logarithmic, and a reduction in level is HEARD as "half as loud." The reason we go 6-10 dB below clip is that distortion in cheap audio stages starts rising in the range of 6 dB below clip, so we make our signals cleaner if we back it off by that 6-10 dB. .
This procedure works for ALL audio output stages and all radios, and is not limited to Signal Link (which, by the way, is not that great a sound card).
This procedure sets the level for the computer output. You still need to follow instructions in the K3 (or KX3) manual to set levels in the radio itself.
73, Jim Brown K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
