[Heath] SB-101 100khz crystal ajustment - revisited

[Jerry Rego]

Back in December I posted a thread on an alternative to adjusting the SB-101 100hz capacitor to 'zero' beat it to the aproppiate frequency.  We went through a lot of ideas.  I ended up taking a rig with a digital readout and pluging it into a dummy load and setting it to 5 watts and trying to adjust the 100 hz capacitor from there.  It came pretty close, but not close enough to adjust the dial as I changed bands to set the pointer to zero.

As I was sitting one night listening to the old man international single sideband net, I sat and tweeked the tuning dial so 90% of the people transmitting didn't sound like lurch or micky mouse.  I had been doing this for about a week everytime I tuned into the net.  

Then it hit me.  I had a an almost perfect frequency reference.  If the voices were sounding "natural" for 90% of the people on the net I must be pretty close if not dead on.  So I slid the marker over the frequency that the net was on and didn't move it.

I set the sb-101 to cal and turned the tuneing dial over to zero and I heard the tone.  I was in lowerside band (you can be in upper side band) and adjusted the capictor until I no longer heard the tone.  I turned it to upper side band and adjusted the capacitor out and back in until I no longer heard the tone.  I switch back and forth between upper and lower sideband until I got the capacitor 'centered' inbetween the two so I didn't hear the tone in either.

I turned back to the net and it was still dead on.. shut it down and let it cool for a day and turned to a net on a different band and set my dal using the new cal settings.. the dial was dead on on 15 meters, 40 meters and 80 meters.

If someone runs into the problem and wants to tweek the crystal adjustment without using the steps in the manual, I hope this helps.


Gus Rego
AK4YM

via

Jerry_Rego at comcast.net




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