This is useful information. I should be able to get the biggest power dissipators within an inch of the edge so temperature rise may managable without extra heat sinking. I received the SAW filter test boards yesterday, so after the tunable filter matching circuit is validated, I can think about the next version of the receiver.

I won't be at the meeting as I have to limit my travel. My mother has Alzheimer's disease and there are only so many times that I can place her at her sister's house or my brother's house.

73,

John KD6OZH ----- Original Message ----- From: Dick Jansson-rr To: John Stephensen Cc: AMSAT Eagle Sent: Sunday, October 21, 2007 18:11 UTC Subject: More Information

John:

This will be my concluding note on this subject prior to the Symposium. I have tuned the analyses done yesterday and that data follows.

For a single 1.4mil ground plane with a single IC located 52mm from the Baseplate edge, a 1.0W dissipation results in a temperature rise of 38.2°C

For a double 1.4mil ground plane with a single IC located 28mm from the Baseplate edge, a 1.0W dissipation results in a temperature rise of 21.1°C.

For a double 1.4mil ground plane with TWO ICs, spaced 40mm and both located 28mm from the Baseplate edge, a 1.0W dissipation in each IC results in temperature rises of 26.1°C (one at 26.0 and the other at 26.2). Total dissipation here is 2.0W.

In other words, doubling the ICs, with this spacing, only added ~24% to the temperature rise. This shows you how this module design handles the kind of power situations that you have in the URx.

See you in Pittsburgh?

'73,

Dick Jansson, KD1K

kd1k@amsat.org

kd1k@arrl.net