RF Chain Details

This closeup shows the Second Local Oscillator and IF Mixer. The TUF-1 mixer is hidden under the output header. I had to put a regular header where called for in the circuit, then carefully trim it and solder a right angle header to the upright one in order to get around the mixer. I couldn't put the header on the other side of the board, as I used two 2-56 nuts as standoffs, to ensure clearance for any pins sticking out of the board while giving maximum clearance above.

The second IF amplifier, a 2N5109 bipolar transistor (a very common driver device, +10dB if I remember, but good to about 2.5W) runs really hot. You can feel the heat with the enclosure top in place. I may add a heatsink to this device just to keep it from toasting...

By the way, I found it very helpful to label the ground pin on every header, right on the board. Since the majority of the cables are coaxial (for better shielding), it's easy to make sure you have the header installed correctly on the pins. My headers were not locking, so it was easy to make a mistake...