I'll have to make some more measurements, but Paul's seem to have much less gain compression than mine. (0.6 vs 1.4 dB from 1 kW to 1.5 kW) That's also closer to the specs for a pair of BLF88XR's.
73, Scott K9MA ------ Scott Ellington --- via iPad > On Jun 15, 2018, at 11:24 PM, Paul Baldock <p...@paulbaldock.com> wrote: > > I received my KPA-1500 yesterday (#244) and did some linearity tests today > > 14.2MHz, Dummy Load, ATU Bypassed. Using KPA-1500 internal Power Meter. > Continuous carrier. > > 10W drive, Gain = 15.6dB 180W > 15W drive, Gain = 15.8dB > 20W drive, Gain = 15.9dB > 25W drive, Gain = 16.0dB 1.0KW > 30W drive, Gain = 15.9dB > 35W drive, Gain = 15.7dB > 40W drive, Gain = 15.6dB > 43W drive, Gain = 15.4dB 1.5KW > 45W drive, Gain = 15.4dB 1.57KW > > Based on this it look like about .6dB compression at 1.5KW. I think that's > pretty good for an SS Amp. > > I also measured the gain on all the bands at 1.5KW out. Drive varied from 31W > on 80M to 47W on 15M. or 16.8dB to 15.0dB. That amount of variation is rather > disappointing. > > I also noted that the internal power meter is pretty inaccurate at low > levels. For Example at 50W on 20M it reads 43W. Its pretty close above 300W > and right on at 1.5KW where its calibrated. > > I would be interested to see any data that others have collected. > > - Paul KW7Y > > > At 02:26 PM 6/14/2018, K9MA wrote: >> The gain compression I measured, between 1000 and 1500 W on 40 meters, was >> 1.4 dB. I used the K3 and KPA1500 power meters. Factory calibration of the >> KPA1500. >> >> Scott K9MA >> >> ---------- >> >> Scott Ellington >> >> --- via iPad >> >> > On Jun 14, 2018, at 2:51 PM, Paul Baldock <p...@paulbaldock.com> wrote: >> > >> > What you report of compression near the maximum power is certainly true of >> > the amplifiers like the SPE-1.5K that use a single device, but I would >> > have thought this would not be true of the KPA1500 that uses 2 devices. >> > This is the reason I returned my SPE and ordered the KPA. Hopefully the >> > compression is less than 1dB. >> > >> > Has anybody else measured it? >> > >> > - Paul - KW7Y >> > >> > >> > >> > At 02:21 PM 6/9/2018, you 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 >> >> p...@paulbaldock.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 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 arch...@mail-archive.com
