You might find some answers here: https://www.dj0ip.de/antenna-matchboxes/ On the next page he shows all the results from published data.
David G3UNA > On 14 July 2021 at 07:29 Julia Tuttle <[email protected]> wrote: > > > That doesn't actually answer the question "what are manufacturers measuring > when they quote 10:1 matching ability?", and makes a gross and insulting > generalization about the quality of equipment produced for the amateur > radio market. > > On Wed, Jul 14, 2021, 01:45 Ray <[email protected]> wrote: > > > The Statement "This tuner will tune an 8:1 mismatch." > > Is made in an Armature world, buy an Amateur person, > > Not for a Professional Product by Calibrated Test Equipment. > > This is Not New, it has happened for Decades. Buyer Beware. > > WA6VAB Ray K3 > > > > > > From: Al Lorona > > Sent: Tuesday, July 13, 2021 9:32 AM > > To: [email protected] > > Subject: Re: [Elecraft] Question about antenna matching > > > > Thanks to Al N1AL, Jack W6FB, and Dave AB7E for great information that > > helped me a lot. > > > > I'm in the circuit simulation business, after all, and I confess that I > > was just being lazy, so I ran some simulations that confirmed what Dave, in > > particular, had said. > > > > As suggested by Dave, I chose typical Q values of 100 for the inductor and > > 1000 for the capacitor. Then I simulated as many points as I could on the > > entire Smith Chart to see 1/ if the tuner could tune each point to 50 ohms, > > and 2/ what the power loss was in the tuner at each of those points. Then, > > I discovered that K6JCA had already done this on his excellent blog at: > > https://k6jca.blogspot.com/2015/03/notes-on-antenna-tuners-l-network-and.html > > . The > > guy is totally professional and exhaustive in his discussions. I really > > admire his work. > > > > Anyway, it turns out you can make a graph of power lost in the tuner > > versus phase angle of the load. As you might suspect, 'easy' loads of 5 or > > 500 ohms resistive (SWR = 10:1) don't tax a tuner as much as reactive loads > > do. In fact, they're near (but interestingly, not at) the areas of > > *minimum* power loss. > > > > Whenever an antenna tuner is reviewed in QST, resistive mismatched loads > > are usually used. I'd like to see tuners tested with reactive loads, but > > the number of loads required to do this from 160 to 10 meters would be > > enormous. I see why resistive loads are preferred, because you can re-use > > the loads on every band. > > > > I'm frustrated by imprecise statements like, "This tuner will tune an 8:1 > > mismatch." What does that mean? There has to be a better way for > > manufacturers to spec the exact impedance ranges that their tuners will > > tune. I like the method that I used, which shades a Smith Chart in color > > based on the two criteria I listed above. One picture would tell you all > > about a tuner's effectiveness. No real tuner can tune the entire Smith > > Chart, but the more of the chart that is covered, the better the tuner. And > > if you can shade the areas of higher tuner loss in red, then that would > > also tell you an important piece of information. (However, to generate such > > a plot through measurement you'd probably need a very expensive load-pull > > setup, which is a totally separate discussion.) > > > > For the L-network I simulated, a particularly difficult 10:1 load was near > > the 7 - j30 ohm point, which is toward the bottom edge of the Smith Chart > > at a phase angle of 282 degrees (or -77 degrees), and a similar point near > > the top edge. The lower impedances with capacitive reactance were > > definitely the most difficult (using power loss as the measure of > > 'difficulty') for the tuner to handle, which Dave stated in his post, while > > the high impedances with inductive reactance were generally more difficult. > > If your antenna must be mismatched, and you're using an L-network tuner, > > you want it to be > 50 ohms with a little bit of capacitive reactance, or > > below 50 and inductive. > > > > By the way, K6JCA actually put the Elecraft KAT500 through this simulated > > evaluation and it tested so well that he ended up buying one. > > > > > > Al W6LX/4 > > > > > > ______________________________________________________________ > > 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] > ______________________________________________________________ > 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]
