6L6 based transmitter with a spotting function. Over the years it has gone through several iterations to the "Dingey Size Boat Anchor" I use today. Along the way I added a loading control, regulated the oscillator plate voltage to 108 volts, shifted the output circuit to a pi network and repackaged it in a metal cabinet to better match my HRO Sr. Like many projects it has been a journey. Here are a few more details about this transmitter as it stands today.
When changing crystals or, especially, coils it is important to recognize where high voltage is exposed. In this case the unprotected meter terminals have 300 VDC, a lethal voltage, on them. Power this transmitter down when under the covers. This is even more important when working under the chassis. Don't take chances. Power down before working on it. As a safety modification consider placing the crystal socket on the front panel.
Are you looking for something more modern looking? Try W1TS's 6C4-5763 MOPA in the October 1968 issue QST. Just add a resistor and 0B2 to regulate the oscillator B+ to 108V and include a switch to run the oscillator stage while keying the final.