Patrick Henigin's Comments

Hi Patrick
I just wanted to say howdy to you sir...and
Thank you for joining the group !
We look forward to getting to know you better.
Chuck

Hi Patrick
In reference to your question about the interface...the sound card will just be able to supply enough energy to activate the interface circuit. You have to turn your sound card all the way up. The circuit rectifies the sine wave from the audio out of the sound card and stores that energy into the three capacitors. The stored postitive voltage goes through the 1k resistor to open the base of the keying transistor and throws the collector to ground, thus, turning on your rigs keying jack, or the PTT switch of your radio, if you are using FLdigi for AFCW mode.
If you are going to use the interface for normal cw keying of your rig, make sure that you put two rf caps to ground at the junction of the 2ndary isolation xformer and the diodes, as the GOOGLE DOCS suggest. Otherwise, the RFI will be rectified and keep the switch open etc...