Build the KN-Q7A 20m Version from the 40m PCB CRKITS.COM July 26, 2012 Revised: Oct 16, 2012 The KN-Q7A kit was initially introduced as a 40m band only SSB transceiver. This application notes introduces how to leverage the 40m PCB to make the 20m version. Actually the 20m kit comes with the 40m PCB. If you have read the KN-Q7A manual, you will be impressed by the step-by-step process. If you haven't read the manual yet, you are encouraged to download and review it now, BEFORE you actually start the soldering. The manual locates at http://crkits.com/knq7amanual.pdf . Rules • There is no change for resistors, diodes, relays or 104 ceramic capacitors. • In the following steps numbered in the same way as the manual, the red lined components should be either replaced by new components with other value, or simply removed. • The manual photos are for V2.1 PCB while the photos in this document are for V2.1a PCB, so some minor changes can be seen and should not cause confusion. Step 1: Power Supply Circuit. • There is no change. Step 2: Audio Amplifier. • There is no change. Step 3: Detector / Double Sided Band Modulator. • Change the 22uH inductor to 15pF ceramic capacitor. • Change Xa to 20m band IF crystal.