or Tap the PWR button the kpa500 and watch the digital display on the amplifier. Gary
On 16 June 2016 at 13:50, Jack Brindle <[email protected]> wrote: > Fred’s assessment is correct - the output power resolution below 25 watts > is pretty low. But it is still putting out power, at least to a point. > There _is_ a lower limit to input power - it involves the ability of the > frequency counter to do its job. If the counter cannot get an accurate > count, it won’t be able to corroborate the frequency for the correct band > selection. This level is in the neighborhood of 1 watt, giving you some > range to play with. > > Enjoy playing with your KPA500! > > Jack, W6FB > > > > On Jun 15, 2016, at 7:15 PM, Fred Jensen <[email protected]> wrote: > > > > Hmmm ... I guess first question is, what's the problem? 25 W to 20W is > slightly less than 1 dB, 0.16 S-unit. Just run barefoot? > > > > The LED Power display on the KPA500 is digital. It "measures the > power," and puts it into one of a number of bins. If something is in the > bin, it lights the LED. If the measured power isn't high enough for the > lowest bin, all the bins are empty, no LED's light up, although there is > still RF being made. > > > > Measuring power with simple instruments is hard ... well, sort of > impossible. You can measure the voltage, but then you need to know the > impedance, a complex number, not easily measured with a DVM. You can > measure the current -- same problem. KPA500 is designed to emit 500W with > 25-30W input. I think you're pushing the envelope here and nothing is > wrong. > > > > 73, > > > > Fred K6DGW > > - Northern California Contest Club > > - CU in the Cal QSO Party 1-2 Oct 2016 > > - www.cqp.org > > > > On 6/15/2016 4:54 PM, James Bennett wrote: > >> I share my KPA500 with a K3 and a KX3. When I want to operate JT65 or > >> JT9 I normally run about 25 watts out, using the KX3 to drive the > >> amp. With the KX3 set to 1.8 watts out, the amp gives me 25; with 2.2 > >> watts from the KX3, I get 30 watts out from the amp. > >> > >> But, what if I want to run 20 watts? Or 15? When I back the KX3 power > >> level below 1.8, the KPA500 shows zero on the LED power display. Does > >> this mean it is no longer amplifying, or is it actually amplifying > >> but not enough for the circuitry to determine how much? > >> > >> Jim Bennett / W6JHB Folsom, CA > > ______________________________________________________________ > > 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 > > Message delivered to [email protected] > > ______________________________________________________________ > 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 > Message delivered to [email protected] > -- *Gary - VK1ZZ, K3NHLSkype: Gary.VK1ZZhttp://www.qsl.net/vk1zz <http://www.qsl.net/vk1zz>Motorhome Portable* *Miss Behavin'* *Elecraft K3KPA500FT #18KAT500FT #007* ______________________________________________________________ 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 Message delivered to [email protected]
