Juan: Can you "sniff" the various lines from CAN-Do! to get an idea of which is the source?
Also, my memory is that we still have an open issue with the passband ripple -- or did that get resolved and I missed it?
Again, thanks for all you're doing.
73, Jim wb4gcs@amsat.org
Juan Rivera wrote:
All,
The source of the spurs in the 70 cm prototype receiver is the CAN-Do module.
*This is the receiver IF output as designed*
*(powered from pins 39 and 40 of the CAN-Do Module)*
*This is the receiver running off of a separate power source*
*(bypassing the CAN-Do Module +13 volt output on pins 39 and 40)*
*This is the same configuration as above, but with the CAN-Do module shut down*
From the above it appears that:
The CAN-Do module is the source of all the spurs that I see
None of the spurs are being generated by the receiver's internal
power supplies
- Some, but not all, of the noise is entering the receiver via the
switched +13 volt CAN-Do output on pins 39 and 40
- The remainder of the noise could be entering the receiver on
other CAN-Do pins, or being radiated to receiver components or traces in close proximity
See my log for all the intermediate steps I took to reach these conclusions.
Remaining RF issues:
Phase noise
Microphonics
73,
Juan
WA6HTP
