Joe, Just to clarify, the last measurements were on 28.447.44 (a clear frequency here at the moment), SWR is 1.1:1, tri-band yagi.
On 12 May 2011 08:40, Gary Gregory <[email protected]> wrote: > Joe, > > 325W @ 15W drive > 410W @ 20W drive > 490W @ 25W drive > 510W @ 26W drive > 530W @ 27W drive > 560W @ 28W drive > 580W @ 29W drive > 600W @ 30W drive > 630W @ 31W drive > 650W @ 32W drive > 675W @ 35W drive > 690W @ 37W drive > 700W @ 40W drive > > Is this still about right for your calculations..... > > Gary > > > On 12 May 2011 08:18, Joe Subich, W4TV <[email protected]> wrote: > >> >> Adding gain calculation ... >> >> >> > 2W = 30W 11.8 dB >> > 2.5W = 40W 12.0 dB >> > 3w = 50w 12.2 dB >> > 3.5w = 60w 12.3 dB >> > 4w = 70w 12.4 dB >> > 4.5w = 75w 12.2 dB >> > 5w = 80w 12.0 dB >> > 5.5w = 90w 12.1 dB >> > 6w = 100w 12.2 dB >> > 6.5w = 110w 12.3 dB >> > 7w = 120w 12.3 dB >> > 7.5w = 130w 12.4 dB >> > 8w = 150w 12.7 dB >> > 8.5w = 160w 12.7 dB >> > 9w = 170w 12.8 dB >> > 9.5w = 180w 12.8 dB >> > 10w = 190w 12.8 dB >> > 11w = 200w 12.6 dB >> > 12w = 225w 12.7 dB >> >> The numbers look about right including the decreased gain at low level >> (as expected). Using 12.6/12.7 dB would indicate 33W drive for 600W >> out. 40W drive for 600W output would indicate ~1 dB of compression. >> >> 73, >> >> ... Joe, W4TV >> >> On 5/11/2011 5:28 PM, Gary Gregory wrote: >> > Stan, >> > >> > Allow some variation to antenna variations also. >> > >> > This on 15M, swr is 1.0:1 >> > >> > 2W = 30W out >> > 2.5W = 40W >> > 3w = 50w >> > 3.5w = 60w >> > 4w = 70w >> > 4.5w = 75w out >> > 5w = 80w >> > 5.5w = 90w >> > 6w = 100w >> > 6.5w = 110w >> > 7w = 120w >> > 7.5w = 130w >> > 8w = 150w >> > 8.5w = 160w >> > 9w = 170w >> > 9.5w = 180w >> > 10w = 190w >> > 11w = 200w >> > 12w = 225w >> > >> > NOTE to ALL: This was not done with lab equipment or even a dummy load. >> This >> > was measured using a K3 and a tri-band yagi and a cw tone. >> > >> > Gary >> > >> > On 12 May 2011 07:13, Al Lorona<[email protected]> wrote: >> > >> >> It's very easy to measure the 1-tone gain compression characteristics >> of an >> >> amplifier. The desired result is a graph of Pout vs. Pin, with Pin on >> the >> >> horizontal axis and Pout on the vertical. >> >> >> >> So what one needs to do is set Pin to the amp, and measure Pout into a >> >> dummy >> >> load. If you do this for several values of Pin, you'll be able to plot >> all >> >> of >> >> those measured points on the graph. It will look like a pretty straight >> >> line >> >> toward the lower Pin values, then it will flatten out (become more >> >> horizontal) >> >> as Pin (and Pout) get higher. >> >> >> >> The slope of the line is the gain of the amplifier. >> >> >> >> Very often the Pin values are 1 dB apart. One dB is about a 25% >> increase in >> >> power. Meaning that if you are measuring Pin in Watts, then you can set >> Pin >> >> to >> >> roughly the following values: >> >> >> >> 1, 1.5, 2, 3, 4, 5, 7, 10, 13 Watts, etc., >> >> >> >> and measure the Pout at each value. The values should be converted to >> dBm >> >> before >> >> plotting. That's all there is to it. >> >> >> >> This is all done in CW mode. If you want to go further, you can go into >> SSB >> >> mode >> >> and apply two tones to the amp (which a K3 has the ability to do) and >> then >> >> look >> >> at the output of both the K3 and the KPA500 with a spectrum analyzer... >> but >> >> I'll >> >> leave that explanation for another day... or it can be found on the >> web. >> >> >> >> Al W6LX >> >> ______________________________________________________________ >> >> 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 >> >> >> > >> > >> > >> ______________________________________________________________ >> 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 >> > > > > -- > > VK4FD - Motorhome Mobile > Elecraft Equipment > K3 #679, KPA-500 #018 > Living the dream!!! > > -- VK4FD - Motorhome Mobile Elecraft Equipment K3 #679, KPA-500 #018 Living the dream!!! ______________________________________________________________ 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
