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

[email protected]

[email protected]