Hi Larry, could you provide more details about this circuit? I tried it but it didn't work.
Tie the output of the regulator to amplifier PTT (5V active high)
Connect the gnd pin of the regulator to the PTT circuit of the rig.?
So when the PTT provides a ground to the regulator, it switches on, and 5V is used to activate the 50W amp.
I understand the on/key-down state here. But what about the off/key-up state? IIUC, when the rig is in off/key-up sate, the ground pin of 78L05 is floating and I believe in that case, the output and the ground pin will both see a voltage at about 1V less than the input voltage. In the attached picture below, pin1 is Vout, pin 2 in Gnd, and pin 3 is Vin. The inner pin of the DC ?connector is at about 11.6V. With pin 2 floating, I measured 10.6V at both pin 1 and pin2 which means if pin1 is connected to the 50W amp's active high PTT, the amp will always be in the TX state. Did I missing something?
73 de Zhenxing N6HAN
