Isn't the issue the rate of change of the temperature of the baseplate?
The minimum storage temperatures for most components is -65 C and the SAW filters are -40 C.
73,
John KD6OZH ----- Original Message ----- From: Dick Jansson-rr To: juan-rivera@sbcglobal.net ; 'John B. Stephensen' Cc: 'David Smith' ; 'Dave Black (Work)' ; 'Dave Black (Home)' ; eagle@amsat.org ; 'Samsonoff@Mac. Com' ; 'Juan.Rivera (Work)' Sent: Saturday, July 28, 2007 18:32 UTC Subject: RE: [eagle] Receiver Spec vs. ATP, a few Suggestions and a Question or Two
Juan:
I do not know how you can be concerned with storage temperatures of -60°C when you have just soldered a PCB with temperatures of from two to a a few hundred degrees! It seems to me that the stress of soldering would vastly exceed those of a low storage temperature. The thermal excursions of soldering considerably exceed those of the storage situation.
'73,
Dick Jansson, KD1K
kd1k@amsat.org
kd1k@arrl.net
From: eagle-bounces@amsat.org [mailto:eagle-bounces@amsat.org] On Behalf Of Juan Rivera Sent: Saturday, 28 July, 2007 05.23 To: 'John B. Stephensen' Cc: David Smith; Dave Black (Work); Dave Black (Home); eagle@amsat.org; Samsonoff@Mac. Com; Juan.Rivera (Work) Subject: [eagle] Receiver Spec vs. ATP, a few Suggestions and a Question or Two
John,
· (snip)
I also take issue with the -60C minimum power-down temperature. I think this is unrealistic just from a CTE mismatch perspective. The reliability of anything subjected to that wide a temperature spread is going to suffer. A way must be found to raise that temperature.
(snip)
73,
Juan - WA6HTP