Re: Digital communications with a USB sound card - dumb mistake #ubitx
For sound interfacing, I decided the best route was to keep as
much inside the box as possible. The mic and speaker jacks are
wired so that if nothing is plugged in, they default to the
Easy-Digi board audio transformers. These are connected to a 6
dollar USB sound dongle plugged into a 4 port USB adapter (room
for a RTLSDR panadapter later on). A 330 ohm resistor is in
parallel with the audio out to the mic-in on the sound dongle to
make volume adjust less sensitive.
For heat dissipation, I used the outer shell of an old car audio amp (almost 2 pounds of solid aluminum), and mounted the PA finals directly to the case by moving them underneath the main board. I also re-purposed one of the original heat sinks to the 7805 regulator. That puppy gets pretty warm without a little help.
Ignore the cardboard front and back panels. Those are temporary until I print out the permanent ones.
The 3 color LED strip also acts as a transmit light. Only blue
and green are on with power, and red turns on for transmit.
On 5/15/2018 4:18 PM, Bo Barry wrote:
Whoops, a USB sound card gives you stereo sound output. Plugged into the mike connector for digital work it activates the PTT line with the audio!