In keeping with my purchasing habits (I own the K1/2 and KX line) I'd rather see a compact, efficient, external, 1 W in /25W out (14dB) packer type amp offered to compliment my very versatile station. Just saying.
72 Myron WVØH Printed on Recycled Data > On Feb 23, 2017, at 1:00 AM, Rick WA6NHC <wa6...@gmail.com> wrote: > > Excellent replies so far. > > What we start with is a ten watt radio. We add the KPA3, which provides a > jump in output by 10 db. We can add the KPA500 which provides another ~12 > db; because you're now loafing the KPA3, keeping linearity 'manageable'. > (Yes, you can push the KPA500 to 600 watts on many bands, but the IMD gives > less return on that power investment.) > > This has been very successful as a model for Elecraft. I don't see any need > for it to change (but without restarting another thread, a KPA1500 with a > KAT1500 matching tuner *would* be awesome). > > If the user wants to run at 25 watts, use a K3(s)/100. It's a simple macro, > computer command or knob twist to reach 25 watts and the signal will be > sparkling clean. But I also note that if 25 watts was a hard limit, my > KPA500 could not be driven to full output on all bands, a couple require more > input. > > Let's not mess with success... This is one case that fewer options (not > having a 25 watt amp at max OR having it biased into class A, using more > energy) is a good thing. > > 73, > > Rick wa6nhc > > >> On 2/22/2017 8:30 PM, Cameron Francey wrote: >> Thumbs up here to this reply! >> >> Also, if you have 25 watts max from the rig then you limit your ability to >> reduce to 100 watts or less where its more than enough. >> >> Remembering that we use the least amount of power needed to maintain the >> contact. Just because the gas peddle goes as far as the floor doesn't mean >> it needs to be pushed that far to get to the shops! >> >> >> Best regards, >> >> Cameron -AF7DK/GM7LQR >> >> >> ________________________________ >> From: Elecraft <elecraft-boun...@mailman.qth.net> on behalf of Matthew Cook >> <vk...@bistre.net> >> Sent: Wednesday, February 22, 2017 7:32 PM >> To: Harry Yingst >> Cc: Elecraft Reflector >> Subject: Re: [Elecraft] Product Idea - 25 Watt PA for the K3 >> >> To make this idea work you need to make a 25Wpep amplifier that is kept in >> it's linear region so that the IMD from this amplifier does not cause >> problems in the output of the KPA500. >> >> To make a class A-B 25W amplifier such as this with enough linearity will >> result in you designing an amplifier capable of 100Wpep at full smoke. The >> non-linear nature of HF PA's is easily found on the net. Having designed >> PA's for HF manpacks a number of years ago we simply turned down our >> 100Wpep design to 25Wpep and pocketed the performance increase at the >> expense of cost. >> >> The K3/100 at 25-35W has excellent linearity (highly likely by design, pat >> designers on back for this one) which allows a more aggressive approach >> within the KPA500 for grunt at the expense of "some" linearity. You're >> not increasing the cost of the KPA500 trying to eeek out every last bit of >> linearity to get around the rubbish coming from the transceiver. >> >> I'm keen to do some measurements in the near future of the SPE 1.3k-fa >> amplifier being driven by a K3/10. Having measured the IMD of my the >> K3/100 at 10W (KPA3 disabled) recently I was a little surprised at the >> result, it was not as clean as when driven at 30W with the KPA3 enabled. >> I'd not be surprised to see some output degradation in the SPE from the >> K3/10 c.f K3/100 driven at 20W with a -3dB inline attenuator. This would >> certainly explain some of the "wide" local signals that I've been seeing in >> my SDR recently. >> >> Engineering is always about compromise, and cascaded amplifiers are one of >> the more trickier things to strike the right balance with. >> >> 73 >> >> Matthew >> VK5ZM >> >> On 23 February 2017 at 07:55, Harry Yingst via Elecraft < >> elecraft@mailman.qth.net> wrote: >> >>> Seeing how the KPA- 500 tends to need less than 25 watts to drive it to >>> full output (500 watts) It got me thinking about a 25 watt PA Option. >>> Would it be possible to replace the existing 10 watt PA board with a 25 >>> watt PA board that would use a larger heatsink instead of the case. >>> >>> If the stock Filters and Relays can handle the 25 watts it would seem that >>> it would be a more inexpensive option for those who plan on going with the >>> KPA500. >>> >>> Just a thought... >>> >>> >>> >>> >>> ______________________________________________________________ >>> 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 vk...@bistre.net >> ______________________________________________________________ >> 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 cameronfranceyut...@hotmail.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 wa6...@gmail.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 thelas...@gmail.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
