I'm starting design work on a two-tube (two-valve, for those who prefer that term) reflex-regen receiver that I hope will cover AM broadcast through 160m-10m -- both amateur bands and those "in between" spectrum segments including SW broadcast bands.
Longer term, I'd like to build this into a transceiver, with at least CW transmit and possibly a later upgrade to AM or even SSB.
Part of the definition of a transceiver is that parts count is kept under control by sharing parts of the circuits -- the audio amplifier in a receiver might be reconnected as the voice modulator for AM transmission, for instance, almost always the antenna is shared, and in older handy-talkies (especially the "toy" variety) the speaker becomes the microphone.
What I'm wondering is whether it's practical, without sacrificing desirable qualities like stability, to make the receiver's tuning tank circuit also act as the tuning section of the VFO for transmit. It seems so, at first glance -- we've got a tuned network already set to resonance at the selected frequency; at most we might want (for CW, especially) to offset the transmitter by a small amount, easily done by switching in a low-value capacitance.
Most of the transceiver schematics I've looked at, however, were either very simple circuits that really only share the power supply and antenna, are crystal controlled without the ability to genuinely tune either receive or transmit, or are so complex I can't be sure I'm following the functions correctly (ex. the 22 tube Heathkit SB-102).
So, is it practical or advisable to expect to use the same tuned circuit to control both receive and transmit frequency in a VFO-controlled transceiver?