[eagle] CAN-Do Causing RF Frequency Jumps in 70 cm Receiver

Juan Rivera juan-rivera at sbcglobal.net
Mon Jul 2 21:25:00 PDT 2007


John and CAN-Do Team,

 

I was in the process of checking some configuration files in preparation for
my hunt for the 10.7 MHz spur.  I initialized the receiver on 435.500,
internal reference, and set up the SDR-IQ to display the IF output signal.

 

Then I clicked the heartbeat button on the Can-Do Net Controller and was
about to load the initialization file for external reference.  As soon as I
clicked the heartbeat button the IF output started jumping.  I think it's
the three second jumps that I have seen before, but I thought those were
caused by a momentary loss of DC input power.  In this case the receiver
power is coming directly from the bench supply.  I killed the CAN-Do module
power and the IF jumping stopped.  As soon as I applied power to the CAN-Do
module again, the jumping returned.

 

The duration of the jumps is very short and I am unable to capture a carrier
- either with the SDR-IQ or using my TS-2000.  They sound like clicks over a
wide frequency range.

 

Since the next revision of the receiver will be autonomous, perhaps this
won't be an issue for us, but it will for others so it should be understood
and documented in my opinion.

 

73, Juan

 

 

 



 

 

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