Using a 6BW6 vacuum tube, the above transmitter delivers about 5 W output. CI is adjusted for cleanest CW note. C8 and C9 are 365 pF and dual-365 pF (paralleled) tuning capacitors. LI is 35 turns of #24 enamelled wire on a 1 plastic tube. FT-243 crystals for 3.5 or 7 MHz are used.
Do not use this circuit to produce a 7-MHz output from a 3.5-MHz crystalit is not intended to double over crystal frequencies.