> Jan Erik Holm wrote: > > > > Bill and others, hold on and think about these > > figures. -35 to -38 dB IM3 !! We are dealing > > with 2SC2782 transistors operating at around > > 12V DC. I say no more, the knowledge and intelligent > > individual will understand.
I would be careful here ... the Toshiba 2SC2879 data sheet clearly does -38dB IMD at 60 watts with VCC=12.5V. There are certainly devices capable of that level of performance means that there are devices capable of that level just as there are devices capable of similar levels of performance at 120-140 watts per device with Vcc=28V. I would expect the 2SC2879 to also be capable of this level of performance ... if not, I would have expected the design of the KPA3 to have been based on another device. 73, ... Joe, W4TV > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Bill W4ZV > Sent: Monday, January 26, 2009 4:18 PM > To: [email protected] > Subject: [Elecraft] SSB IMD > > > > > > Jan Erik Holm wrote: > > > > Bill and others, hold on and think about these > > figures. -35 to -38 dB IM3 !! We are dealing > > with 2SC2782 transistors operating at around > > 12V DC. I say no more, the knowledge and intelligent > > individual will understand. > > > > Which reminds me...I set my power supply to deliver 14.5V at > the input to my K3 terminals under load. Although the power > supply specification says... > > "Supply Voltage/current: 13.8 V nominal during TX. (11 V min, > 15 V max). 17-22 Amps typical in TX (100W). 0.9A minimum RX." > > ...I would never intentionally run mine at the lower end of > that range. If you have any concerns about overshoot when > turning on your power supply, always turn the PS on a few > seconds before the K3. I tend to leave my PS on continuously > so overshoot is never an issue. > > IMD performance should be much better at the upper end of the > voltage spec than at the low end...and I believe I've seen > Eric or Wayne recommend this previously but have not searched > for the exact quote. > > I'll let you tell W8JI he's not knowledgeable and intelligent. ;-) > > 73, Bill > > -- > View this message in context: > http://n2.nabble.com/New-Eham.net-K3-review-by-QRPNEW-tp221808 6p2220726.html Sent from the Elecraft mailing list archive at Nabble.com. _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
