The current readings on the Killowat are showing AC into the power supply. losses in the Astron there and with additional loads it will be drawing more power than the K3 alone. The other question is the Killowatt reading peak currents or RMS. In a perfect world with a 100 percent efficient power supply connected to a K3 drawing 15A at 13.8V. The power supply will draw 1.7A. At 120 V ac. But even the best power supplies especially analogue are far from 100 percent efficient. So your readings are reasonable onto that, and I am sure someone will correct me if I am wrong, the K3 will draw somewhat more than 15A. Key down at 100W so the am meter on the Astron may be reading a little low. Sent wirelessly from my BlackBerry device on the Bell network. Envoyé sans fil par mon terminal mobile BlackBerry sur le réseau de Bell.
-----Original Message----- From: Paul Grigorieff <n1helra...@gmail.com> Sender: elecraft-boun...@mailman.qth.net Date: Wed, 5 Mar 2014 12:16:23 To: Frank R. Oppedijk<fr...@qrd.nl> Cc: <elecraft@mailman.qth.net> Subject: Re: [Elecraft] [K3] K3 Off Grid OK, here are some new readings, taken with a Kill-A-Watt power consumption meter. The readings in transmit mode were taken by keying down in CW for a few seconds and waiting until the meter reading stabilized. I have an Astron 70A power supply powering a Rigrunner that then supplies a K3, a KAT500, and a PigKnob. The P3 is plugged into the K3. There is a set of speakers, which draw .06A AC as well. K3 in RCV mode .92A AC, or 84W 6 DC at 14v K3 in XMIT, 15W out 2.7A AC, or 240W 17A DC " K3 in XMIT, 50W out 3.7A AC, or 342W 24A DC " K3 in XMIT, 100W out 4.7A AC, or 438W 31A DC " How do these look to everyone? I'd like to get them close to right so that I can calculate my battery needs for emergency operation. Something else I don't understand is the ammeter on the front of the Astron. When the K3 is turned on, the Astron's meter jumps up about 1A DC. When the K3 is transmitting at 15W, the Astron's meter reads about 7A DC. At 50W transmitted power, it reads 11A DC. And at 100W out, it reads 15A DC. Quite a difference from the measured and computed DC amps listed above. What is going on here? Simply an innaccurate Astron meter? Thanks, -Paul, N1HEL On Wed, Mar 5, 2014 at 2:06 AM, Frank R. Oppedijk <fr...@qrd.nl> wrote: > > My K3, on receive, with the KAT500 in-line, the P3, and my massive 70A > Astron p.s. powering the K3, drew about 20A DC. Putting the K3 in transmit > mode, with just under 12W drive (so as not to kick in the 100w amp) > required about 30A DC. Boosting the output to 50W drew about 70A DC. > Running it "wide open," at 100W out, required about 80A DC. And finally, > turning on the KPA-500, with 15W drive to yield 300W out, required 150A DC. > > I haven't made any measurements myself, but I do believe there must be > some error in your numbers. If RX draws 20A and TX at 100W draws 80A, that > means 60A x 12V = 720W input power to create 100W RF output. The other 620W > must be dissipated into heat, which, I guess, would melt the K3 over time > :) There clearly must be an error somewhere. > > Also, 20A on RX seems way too high for me. The K3 by itself draws 2A on > RX, IIRC. Add an extra 1A for the P3 and the KAT500 maybe, and we're still > missing 17A. > > Was your measurement device faulty, or do you have an error in your maths? > > 73 de Frank PA4N > > ______________________________________________________________ > 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 > -- Paul N1HEL Half Moon Bay, CA ______________________________________________________________ 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 ______________________________________________________________ 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
