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8640 Jr Revisited

 

8640 Jr Revisited

Filed in homebrew on Mar.15, 2015

I’ve had this signal generator project on my bench for a while now. Basic functionality is there, with approximately +7dbm output from 833 kc to 36 mc or so. Now it’s time to put some finishing touches on it, and box it up in a presentable format.

Band 1 covers 833 kc to 1.6 mc. Here is the output (all measurements into a 50 ohm load) The top yellow trace is the output for a frequency counter. The bottom Green trace is the high level output:

 

 
Band 1 Bottom ~833kc @ 6.5 dbm
 

 
Band 1 Top – ~ 1.6mc @ +1 dbm
 
 
Band 2 covers approximately 1.6 mc to 3.5 mc.
 
 
Band 2 Bottom – ~ 1.6mc @ +7 dbm

 
Band 2 Top ~ 3.5 mc @ +4 dbm

 

Band 3 covers approximately 3.5 mc to 6.6 mc.

 
Band 3 bottom ~ 3.3 mc @ +8 dbm

 
 
 
 
Band 3 Top ~ 6.6 mc @ +7 dbm

 
Band 4 covers approximately 6.6 mc to 12.5 mc.
 
 
Band 4 bottom ~ 6.6 mc @ +8 dbm

 
Band 4 Top ~ 12.5 mc @ +7 dbm

Band 5 covers approximately 12.5 mc to 36 mc (extended by fine tuning control).

 
Band 5 Bottom ~ 12.5 mc @ +8 dbm
 
 
Band 5 Top ~ 25 mc @ +8 dbm

I want to use this as a low-level signal generator for receiver testing/troubleshooting as well. That will require some attenuation, which I will cover next.


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