[eagle] Re: CAN-Do noise abatement plan and questions

Robert McGwier rwmcgwier at gmail.com
Thu Jun 14 20:25:27 PDT 2007


John B. Stephensen wrote:
> Bob:
> 
> Were they tested sufficiently for radiation resistance? I'm assuming 
> that the tantalum was used to add radiation shielding for things like 
> flash memory on the MCU. Mirek's receiver also uses flash memory to 
> store the frequency. The PLLs used in the existing 70 cm receiver can be 
> purchased in a pin-compatible rad-hard version. However, the frequency 
> has to be stored in flash memory. PIC MCUs hold data for 40 years on 
> earth but space is a harsher environment.

Yes, the CAN=Do were beat to heck and back in the radiation chamber. 
They will do just fine.  We will test the heck out of the receiver in 
the same manner we do everything else so whatever radiation mitigation 
that needs to be done should be attempted BEFORE the test because the 
desired result is PASSING.




> 
> We have the option of buying PLLs (with more pins) that can be 
> hard-wired to a particular frequency. These PLLs are much more expensive 
> and have longer lead times as they are space rated.

This is an option that we should consider.  I would like more details.
> 
> 73,
> 
> John
> KD6OZH
> 
> 


73's
Bob


-- 
AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair
"If you're going to be crazy, you have to get paid for it or
else you're going to be locked up." Hunter S. Thompson


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