Thank you for the information. RTTY contests are the acid test of an amp....
On Mon, Nov 11, 2019 at 8:35 AM Jim Miller <[email protected]> wrote: > It trips off at 105C. > > It starts warning with a yellow indication at 100c > > Power reduced to 1kw helped slow the rate of temperature increase but > still required a cold room and max fan speed at the beginning to contain > it. It never stopped climbing. > > Jim ab3cv > > On Mon, Nov 11, 2019 at 9:32 AM Fred Massey <[email protected]> wrote: > >> What output power did that reduce too ultimately, is 105c the design >> temp limit? >> >> On Mon, Nov 11, 2019 at 8:30 AM Jim Miller <[email protected]> wrote: >> >>> " I rode the drive power downward as the power increased to stay below >>> the >>> trip point of 105c." >>> >>> Should have been "as the temperature increased" >>> >>> jim ab3cv >>> >>> On Mon, Nov 11, 2019 at 9:03 AM Jim Miller <[email protected]> wrote: >>> >>> > I participated in the WAE RTTY contest this past weekend and was having >>> > problems with thermal tripping. >>> > >>> > I have resonant antennas for 80, 40 and 20m and had SWR between 1:1 and >>> > 1.2:1, power nominally set between 1400-1500w. >>> > >>> > I found that I couldn't repeatedly CQ without temperature creeping up >>> so I >>> > paused to around 50% duty cycle to stop that. >>> > >>> > However when sending QTC which amount to about 200 characters the >>> > temperature would rapidly increase and eventually thermal trip. >>> > >>> > I took several actions to try to compensate: >>> > >>> > I opened the shack windows and bundled up. Shack then stayed at 60f or >>> > below. >>> > I immediately manually cranked the fan speed to max (5) when started to >>> > send QTCs. >>> > I rode the drive power downward as the power increased to stay below >>> the >>> > trip point of 105c. >>> > >>> > Upon taking all these actions I was able to eventually send the QTC >>> > packets but it was unnerving and unexpected. >>> > >>> > This is a low serial number KPA1500 but with latest production >>> firmware. >>> > >>> > What have others seen? >>> > >>> > 73 >>> > >>> > jim ab3cv >>> > >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[email protected] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [email protected] >>> >> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
