Scott, I’m not sure how you’re doing the test, but this is definitely not characteristic.
We test every amp for IMD, and we see an average of about -35 dBc (3rd order, ARRL method) across all bands. This is state of the art for an LDMOS deign running class AB. Other SS amps using similar designs have have similar performance. Any amp’s gain levels off as it approaches peak power (ie, is slightly in compression). But it should not be flat-topping unless it’s over driven or is starved for supply current/voltage. Finally, both the transceiver and amp will vary from band to band somewhat in IMD. You might for example see -40 dBc on one, but in the low 30’s on the other, on a given band. Again, this is typical of all such SS rigs/amps except those running class A or using closed-loop feedback (predistortion). Please call Monday to discuss your test method with one of our technical staff. 73, Wayne N6KR ---- http://www.elecraft.com > On Jun 9, 2018, at 2:21 PM, K9MA <k...@sdellington.us> wrote: > > I recently ran a two-tone test and measured CW power gain. (SN1078) It > doesn't look good. The two-tone waveform shows distinct "flat-topping", and > the power gain drops 25 percent from 1000 to 1500 Watts. My old 3-500Z > amplifier is much better. Has anyone measured IMD or linearity, or seen any > test results? > > While I'm primarily a CW operator, I'd be very reluctant to use the amplifier > on SSB. > > 73, > > Scott K9MA > > -- > Scott K9MA > > k...@sdellington.us > > ______________________________________________________________ > 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 n...@elecraft.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
