Using si5351 for generation the carrier for Drake TR-3

K9SUL

This is a simpler version of a more comprehensive mod. If the filter is bad in your TR-3, but band crystals are all okay, then this is for you.

The value of small dog bone capacitor may vary.

In one of the TR-3s I have, one sideband filter was working fine. I took apart the filter can and saved the working half.

I added a shielding on the bottom of the board and bonded it with the four crystal cans. The filter was then hard-wired to T6 and T13.

A si5351 board of the Adafruit design was used in this mod. It is much smaller than the Etherkit one. The carrier shifting coax was used for sensing X-CW and a wire was run from the sideband selection switch to it as well. I added a 5V supply by rectifying the heater supply and feed it through a 5 volt regulator.