Maybe I'm missing something here, but it would seem to me that if an FET linear amplifier running from 50 V or higher is considerably cleaner than one running from 12 V, that, for a high end rig, a simple step-up switching supply could solve the problem. But, that obviously adds to the cost so it IS somewhat of a conundrum.
However, implementing the pre-distortion function IS probably a better long-term solution. 73, Charlie k3ICH -----Original Message----- From: elecraft-boun...@mailman.qth.net <elecraft-boun...@mailman.qth.net> On Behalf Of David Gilbert Sent: Monday, September 14, 2020 12:43 AM To: Elecraft Reflector <elecraft@mailman.qth.net> Subject: Re: [Elecraft] Why predistortion ? Of course, but that's a conscious choice by Elecraft and it does not result in the "cleanest, purest signals around." I give Elecraft tons of credit for the other measures they have take to produce good signals, which is why I own and will keep my upgraded K3 probably forever, but K8JHR simply was incorrect in his comment and it makes a difference when considering the expanding focus by folks like Sherwood and others to clean up the bands. When it comes to IMD, Elecraft is not one of the better players. The fact that that's by choice doesn't change anything. I suspect that 95+% of K3 rigs are used in portable/emergency situations less than 5% of the time. 73, Dave AB7E On 9/13/2020 7:14 PM, Wayne Burdick wrote: > 12 volts is a severe constraint for MOSFET PAs. But, like a lot of other > manufacturers, we accept this constraint so the equipment can be used in a > wide variety of portable/emergency power situations. As a result we have IMD > numbers in exactly the same range as other products that are subject to this > constraint. > > On the other hand, our transceivers are best in class in terms of transmitted > keying bandwidth. See paper by K9YC for example. Perhaps that's what JR was > thinking of. > > 73, > Wayne > N6KR > > > >> On Sep 13, 2020, at 6:50 PM, David Gilbert <ab7e...@gmail.com> wrote: >> >> >> I don't know where you got the idea that the K-Line produces the cleanest >> signals. As several people have pointed out, because of the 12 volt finals >> the transmit IMD performance of the existing K-line is relatively poor. >> >> Dave AB7E >> >> >> On 9/13/2020 2:32 PM, JR wrote: >>> Why are so many ops obsessed with predistortion? >>> >>> The Elecraft K-Line already produces some of the cleanest, purest transmit >>> signals around. Do we need predistortion ? If so, why, and how much >>> better is it than what we already have? Should I wait to buy a new rig >>> until that is available? >>> >>> Thanks and Happy Trails to all. K8JHR >> ______________________________________________________________ >> 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 >> n...@elecraft.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 pin...@erols.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
