Thats an interesting observation Guy. Anybody out there who can explain? Now, the ATU process is done at low power, so there should be some other explanation why the K3 ATU fails to stop at the best LC combination. 73 Poul-Erik
-----Oprindelig meddelelse----- Fra: guyk...@gmail.com [mailto:guyk...@gmail.com] På vegne af Guy Olinger K2AV Sendt: 26. maj 2011 19:32 Til: Poul Erik Karlshøj (PKA) Cc: David Cutter; drewko; Elecraft@mailman.qth.net Emne: Re: [Elecraft] K3 antenna tuner question Having a lot of water around means that the antenna impedance changes with the power level. I have seen this many times here on 160 with wet leaves very close to wires, and sometimes touching. I can watch the SWR vary under a steady 1500 watts, something not seen or far less obvious at 5 watts. No attempt at explanation. 73, Guy. On Thu, May 26, 2011 at 10:05 AM, Poul Erik Karlshøj (PKA) <p...@tele.gl> wrote: > I don't think the problem is due to good tunes being misses by antenna being > "hit", because when it happens, it is very reproductive, i.e. you can repeat > the ATU tuning and it will always come back to the non-optimum LC combination. > Paul > OZ4UN > > -----Oprindelig meddelelse----- > Fra: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] På vegne af David Cutter > Sendt: 26. maj 2011 14:54 > Til: drewko; Elecraft@mailman.qth.net > Emne: Re: [Elecraft] K3 antenna tuner question > > On 'problem' frequencies, re-doing the tune soon after the first try has > always brought a better swr for me, but I have no wires amongst branches > which I think means you may be getting hit and miss good tunes. > > David > G3UNA > >>A quick way to find the best LC combinations manually is to tune them >>for maximum receiver noise. You can refine this further by using the >>K3's AFV meter to measure the noise level of the different promising >>LC combinations. >> > >> A reminder abou auto tuning-- if you hit ATU TUNE a second time >> within a few seconds of the first tuning operation it is supposed to >> find a better match. However, I have noticed that the second tune >> sometimes gives a worse SWR than the first one. (May be due to the >> variable nature of my antenna-- bare wire through tree branches...) >> >> 73, >> Drew >> AF2Z >> >> >> On Thu, 26 May 2011 07:31:53 -0200, you wrote: >> >>>Another thing about the K3 ATU is, that it sometimes stops at an LC >>>combination which is NOT identical to the LC combination giving the >>>lowest SWR. If that happens you can manually change the L or C to >>>obtain the lowest SWR - but it is a bit cumbersome - and not what you >>>expect from an automatic tuner. I only have this problem when it is >>>raining (antennas are partially hidden in trees and use 450 ohm open >>>feeder and 4:1 baluns in the shack) >>>73 de OZ4UN >>> > > ______________________________________________________________ > 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 > ______________________________________________________________ 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
