You misunderstand me. I never said that being published by the ARRL made it a good design, and in fact I think that the ARRL has a horrible track record for technical integrity on many of their published articles (particularly those in QST). Much of what we read there is just flat out wrong. I merely pointed out that Alpha seemed to think that being published in ARRL gave the tuner design credibility ... an unwarranted association from my perspective.
Dave AB7E On 11/26/2011 8:44 PM, Don Wilhelm wrote: > Just because it was published by the ARRL does not make it a good > design, although it might help to sell a few. > > Zack Lau published a QRP version of that tuner some years back and later > retracted it, and it has not been mentioned much since, but Dean Straw > published his high power version of about the same design and that seems > to be the "best thing since sliced bread" despite counterclaims by noted > authorities on balun and RF designs - W8JI, W7El and others. Bottom > line, it just does not work well, although there will be many who will > say that "Alpha makes good stuff", that still makes it a stretch of the > laws of physics - using an unbalanced network "floating" (although not > really isolated from a common reference (ground)) will still not make > everything balanced. > > I know there are those who will claim that an off center fed dipole has > a balanced feedpoint, but I am not convinced. I put the "balun at the > input" tuners in the same category. Take a balanced signal (output of a > balun) and feed it through an unbalanced network, and claim that the > output of that unbalanced network is balanced just does not make much > sense to me. Maybe with ideal components it *might* be possible, but if > one would plot the reactance and phase delay around that unbalanced > network using good scientific methods, it would become obvious that the > output would not be of equal and opposite currents with 180 degrees > phase difference. If the schematic does not look balanced, it is not > really balanced. Follow the leading current and lagging current around > the circuit to convince yourself. > > 73, > Don W3FPR > > On 11/26/2011 10:10 PM, David Gilbert wrote: >> If I remember correctly, the announcement for the Alpha tuner even >> stated that they "drew heavily" (or words to that effect) from the ARRL >> Antenna Book for the design. >> >> 73, >> Dave AB7E >> >> >> >> On 11/26/2011 6:37 PM, Paul Christensen wrote: >>>> I was surprised to see this from Alpha, whom I would have expected to know >>>> better. >>> The identical design (less automated functions) can seen in recent issues of >>> the ARRL Antenna Book For example, see 20th Ed., pp. 25/15 - 25/19 and >>> titled "High-Power ARRL Antenna Tuner for Balanced or Unbalanced Lines." >>> Even output C is the same at 800 pF max. >>> >>> Paul, W9AC >>> >>> __ >> ______________________________________________________________ >> 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 >> > ______________________________________________________________ > 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 > ______________________________________________________________ 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
