The 68 kHz spacing indicates that the source isn't the PLL as it's phase detector operates at 125 kHz. The switching regulator on the CAN-Do module should be the only device that changes frequency with input voltage.

73,

John

KD6OZH

----- Original Message -----

From: Juan Rivera

To: 'Robert McGwier' ; 'John B. Stephensen'

Cc: eagle@amsat.org ; 'David Smith' ; 'Dave Black (Work)' ; 'Dave Black (Home)' ; 'Samsonoff@Mac. Com' ; 'Juan.Rivera (Work)'

Sent: Saturday, June 09, 2007 20:25 UTC

Subject: RE: [eagle] Re: New 70 cm Receiver Test Results

Folks,

I've bypassed U17, the 10 volt step-down converter, in an effort to isolate the cause of the spurs in the IF output. I've also started a new log. You can jump there by clicking here, or go to the AMSAT 70 cm receiver page and click on Spur Troubleshooting under Project Status.

73,

Juan

WA6HTP