Does the spur go away if the external reference is on (whether or not it is routed to the PLLs)?
73,
John KD6OZH
----- Original Message ----- From: "Juan Rivera" [email protected] To: "John B. Stephensen" [email protected] Cc: [email protected]; "Bill Ress" [email protected]; "Dave Black (Home)" [email protected]; "Dave Black (Work)" [email protected]; "Dave hartzell" [email protected]; "David Smith" [email protected]; "Don Ferguson" [email protected]; "Juan. Rivera (Home)" [email protected]; "Juan.Rivera (Work)" [email protected]; "Samsonoff@Mac. Com" [email protected] Sent: Saturday, June 30, 2007 14:22 UTC Subject: 10.7 MHz Spur
John,
I found the source of the 10.7 MHz spur. It's being generated inside the receiver itself. This is the first spur I have found that is not caused by switching power supplies.
The origin appears to be in the 10 MHz reference area. I turned off and unplugged the SDR-IQ and fed the IF output from the 70 cm Receiver to my TS-2000. The spur is still there.
Next I connected the RF input to my sniffer loop and moved it around the PCB surface. I get the strongest signal near the long trace between the two Freq inputs to U4 and U9, the two phased-locked loops.
73,
Juan