I would like to make a flexible CW TX with a broad coverage of HF,
something like:

VXO or BB BB POWER
AMP TUNABLE BPF
VFO === DRIVER === (2-5W, derated)
=== PLUGIN LPFs
(50-100 mW) AMP (.5 to 1W) RF
TRANSFORMER R/T SWITCHING


I'd like the driver-PA chain to be no-tune and unflappably stable
over, say, 7-15 or 3-30 MHz, with 50 ohm I/O. I guess the driver
stage(s) need not be nondistorting, as a C class PA will produce much
in the way of harmonics to be accurately filtered out, but it would be
nice-to-have. I don't know if a more linear power amp would help, but
I'm willing to use large a derated final and go balanced and/or class
A, with negative feedback, if it helps stability and bandwidth. That
would help spectral purity too, but I see it as a side effect not to
be relied on too much.



I looked around, found plenty of professional ready made gear, but not
much in the way of tips.

I'd be tempted to start as with two low-distortion audio-like stages
with negative feedback and broad bandwidth-limiting, such as small
caps to ground, and large coupling caps + VHF beads in the signal
paths, but it would be trial and error.

Any suggestions on where I should have looked???



tx es 73 de n1jpr/i2