On Mon, 26 Apr 2010, Paul Plack wrote: > Your heatsink approach, however, is exactly what I was talking about. > I have several very large heatsinks originally designed for use with > big SCR switching circuits which look to be more than generous for a > 30w PA at 100% duty cycle. My first repeater was built from a 2w > Repco exciter board repurposed from RFID service. It was supposedly > rated for continuous duty, but had to run very hot to dump the heat it > produced through the little aluminum tab mounted to its own PC board > within the case. I fashioned a new tab with a 90? twist which allows > sinking the little PA to the case itself, and it never got above "warm > to the touch," even after hours key-down. Guys, I appreciate all the > input. 73, Paul, AE4KR
Remember, the 100W Mitrek had a heatsink that was rated for 35W and used the duty cycle to keep things cool. If you do a case swap from a 30W radio into a 100W case, you could be fine for 100%, barring excessive temperature climb. My druthers would be to use an Original Syntor. It's got the helicals of a Mitrek, and the programming of a PROM. At $10 per frequency change (the going rate of the PROM chip), it's still cheaper than the Mitrek and uses the Mitrek/Motrac accessories. -- Kris Kirby, KE4AHR Disinformation Analyst
