Happy Thanksgiving to all.
Well I was very impressed with the NS40 circuit and layout. It took about 30 minutes to build, worked as it should with an RF output of 6.2 Watts into a 53 Ohm resistive load at 12 VDC. The RF signal looked very clean on the oscilloscope and sounded great on the radio.
This is the curcuit I have been looking for for many years. A lot of us hams who got our novice license around 1958 built the standard 6V6GT tube transmitter which had an output of around 7 Watts. The 6V6 transmitter was a simple transmitter circuit and the NS40 is even a simpler circuit than that. Good show to the designers.
I measured the circuit inductors before I built the board and here are the results: L1 - 1.012 uH, L2 - .946 uH, L3 - .749 uH, L4 - .165 uH, and L5 - .480 uH. It will be fun to experiment with and modify this circuit. When I adjusted C4 from 462 pF to 590 pF, the output went from 6.2 Watts to 9.4 Watts with the 53 Ohm load.
I am basically a boat-anchor ham and my rig is shown on my QRZ page.
Thanks again to all involved with this NS40 design,
Bob Luetzow K9ZLU - Lytle Creek, California