On Mon, Aug 7, 2023 at 8:07?AM John Zbrozek <jdzbrozek@...> wrote:
Hi Pierre,
The diode simply is in parallel with the 47uH inductor L14, with the orientation shown in the photo provided by Paul W9AC. Cathode towards the power supply connection, anode to the transformer center tap. Any of the diodes he mentioned (1N4448, 1N4148, 1N914) will do a fine job of absorbing the end-of-transmission voltage spike it produces. I have used a 1N914.
Here you can see simulations with and without the diode present.
On another thread, Evan, Hans and I explore the ability of QDX to withstand SWR. It seems to have a reputation for SWR intolerance but I think there is a case that the problem may actually be as described above.
