If you have nothing to do today, try this: Install Spectrogram on your computer so that you can feed the audio output of your K3 into your computer's line in (or your laptop's mic in).
Scan the input using the following parameters in Spectrogram (I am using version 5.1.7 here): Sample Rate: 11 kHz Resolution: 16 bit Type: Stereo Display Type: Line Channels: Dual Scale: 60 dB Freq Scale: Linear FFT Size: 1024 Spectrum Average: 32 Click on OK to start the measurement. Put the K3 into CW mode and vary the WIDTH control. Look at that fine, flat frequency response that follows your WIDTH just perfectly. I was using this today to help my son visualize what that control does. (You may have to set the K3 volume control to about 12 o'clock to get a good reading in Spectrogram, but this depends on your Windows volume control, whether you have HI or LO audio gain selected on the K3, etc.) Set the K3 WIDTH to 50 Hz and notice the response. Beautiful. Now, turn APF on and watch very closely. Notice what APF does to the peak! Now you know why it can be so effective under the right conditions. I asked you to set the Type to STEREO in Spectrogram, but an interesting thing happens when you set it to MONO instead. After setting it to MONO, set your K3 WIDTH to a convenient width such as 1.0 kHz. Notice the nice, flat response as before. Now, turn on the K3's AFX and see what happens. Change the AFX from Delay1 to Delay5 and see the results. For extra credit, explain what is happening here. Here's a hint: set AFX to "Bin" and notice that the signal goes away completely! My guess is because Spectrogram's MONO mode is essentially L + R, and in Bin mode L and R are out-of-phase and so their sum is zero. Assuming this, can you explain why Delay1 through Delay5 look like they do? Al W6LX ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
