Fixed my PSK keying issue

[N2CHX]

I built a VOX circuit out of an LM324 op-amp and a 2N2222. Connect the input of the VOX circuit to the output of the sound card on the computer and ya got yourself a way to key the transmitter automatically even if you have no serial port to grab a status output from.

Here it is... Took me a couple of hours to build and test. Works very well.

Attachment 3265

It's basically this circuit but I modified it a bit. First, I'm using an LM324 instead of a 1458. I also added a 50k pot in the feedback loop in the first stage, to accommodate anything from mic to hot line level. I changed the 47 uF cap to 22 uF for faster response and changed the 33k resistors in the second stage balancing circuit to 10k for more control. ETA: Oh yes, and my ballast resistors in the first stage are also 10k instead of 47 and my input cap is a 1 uF electrolytic.


Attachment 3266

[N2CHX]

Double post. Not sure how it happened!

[KG4CGC]

Cool set up. You're on a roll and just can't stop!
It's in your blood!

[KG4CGC]

Double post. Not sure how it happened!

You were all excited and stuff about your solution and you just got an itchy trigger finger and it outsmarted the board software.

[N2CHX]

Cool set up. You're on a roll and just can't stop!
It's in your blood!

I think it is. And yeah it feels good to do this stuff again.

[KG4CGC]

I think it's neat how you were able to substitute components and explain why.

[kf0rt]

Threads merged.

Cool vox. ;)

[N2CHX]

Threads merged.

Cool vox. ;)

:) Thanks!

[NQ6U]

You know a lot more about that stuff than I do, Kelli. I could have built the circuit from the schematic but no way I would have known enough about how it worked to make those substitutions. Nice job.