That's one way to go, but note... that while this may work great on RX, heat dissipation MIGHT be an issue on TX.
I'm building a fan controller to control 4 x 120mm fans (1.6A per max) on EITHER the 12V or 13.8V power supplies at our repeater site... I tried using 10A10 diodes to drop the 13.8 VDC down into a reasonable 12+ VDC domain.... Worked fine for low speed... let the fans run flat out and the diodes heated up wayyyyyy too hot without heat sinking AND a fan... they sink on the leads. And the 10A10 is rated to 10 Amps. So... at receive say on a K3s, you'd be sinking at least 1VDC (preferably 2.2 to get to 13.8 nominal) at about 1.16A = 1.16W (or 2.552 Watts with three diodes in series.) Not bad... NOW, TRANSMIT on SSB at 100W on the PA.... 3.55 Amps approx without saying anything.... TALK, and the current draw goes up to 16 Amp peaks... Suddenly, you're asking those little silicone diodes to sink anywhere from 7.81 to 35.2 Watts!!! You ain't gonna do that very long without some thermal control... sinks and active cooling... Just my observations... worth what you paid for them. :-) ______________________ Clay Autery, KY5G MONTAC Enterprises (318) 518-1389 On 7/8/2016 4:55 AM, Bill W4ZV wrote: >> Damage due to using anything over 15 V would void the warranty, since that's > the specified maximum. > > Add in series a couple of silicon diodes (~0.7V drop each) of sufficient > current rating in the positive lead. 16V - 1.4V = 14.6V. > > 73, Bill W4ZV > > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/Upper-power-supply-voltage-limit-with-KX3-tp7619776p7619779.html > Sent from the Elecraft mailing list archive at Nabble.com. > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to caut...@montac.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
