"Mike Andrews" wrote in message
...
In
(rec.radio.amateur.homebrew), Paul Burridge wrote:
Hi all,

Is there some black magic required to get higher order harmonics out
of an oscillator?

The crystal osc itself, probably is sine wave, and therefore has low 5th
content.
Square it up, then pass through a filter, and moderate Q parallel resonant
tank on the 5th harmonic.