RadioBanter - View Single Post - Self-heating of crystal in inverter oscillator

Ben Jackson · July 1st 06, 08:23 AM posted to rec.radio.amateur.homebrew

On 2006-06-30, wrote:
From a stability factor point of view those "inverter" based
oscillators are amoung the worst.

Good to know. I was trying to reduce part count -- the quad XOR provides
the two oscillators plus one mixer.

and I bet there are parameter shifts in the "chip" as it warms up

The other parameter shift I was missing was droop in the 5V rail as
the 78L05 warmed up (rapidly!) and noise injected by a MAX202 charge
pump also on that 5V rail. I thought that regulator was just for an
(unused) LCD header, but I was wrong.

I suggest a discrete Bipolar or FET where you can control the
operating point of the device better.

If I can't tame this VCXO I will try that. This must be how Manhattan
prototyping branches off into "Ugly"...

--
Ben Jackson

http://www.ben.com/