Make sure the heat sink is clean too. Dirty stuff on the heat sink will act as an insulator.
Neil - WA6Kla Paul Finch wrote: > > Jim and Larry, > > Jim is correct, after thinking, about 70 Degrees "C" or 158 degrees "F" is a > good place to not go past. One thing, if you have a good heat sink that is > getting to hot to hold, place a fan on it. They are cheap and a great way > to increase the efficiency of the cooling of the heat sink. Heat speeds the > degradation of transistors, the cooler you can keep them the longer they > will last. > > Paul > WB5IDM > > -----Original Message----- > From: Jim B. [mailto:[EMAIL PROTECTED] > Sent: Thursday, February 17, 2005 9:30 AM > To: [email protected] > Subject: Re: [Repeater-Builder] What PA temp is too much? > > Paul Finch wrote: > > About ten degrees before the transistor starts to boil. Good question > > though. Probably should look at the specifications of the transistor if > > someone can't tell you off the top of their head. Low band should be > fairly > > robust about heat. > > > > Paul > > WB5IDM > > > > > >> Group, > >> > >> If I was to use a thermal activated warning on a PA heatsink of a > >> Lowband Mitrek, what would you think a good "High Temperature" value > >> (in degrees) would be to sound the alert on the controller. > >> > >> Larry, N8RDT > > The rule of thumb I've been using is that if you can't hold your hand on > the heatsink for more then 2-3 seconds, it's too hot. How hot is that? > I'm thinking 130-150 F maybe? > > -- > Jim Barbour > WD8CHL > > Yahoo! Groups Links > > > Yahoo! Groups Links > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
