Semantics. When I say, "It's not necessarily a good one", I mean that just because a match is achieved, it doesn't mean that one should accept the situation. Even though the L-network offers the lowest loss (it doesn't always) it doesn't mean it is "low loss", in fact the loss can be quite high. A simple change in transmission line length might be beneficial.
I can demonstrate that two L-networks in series, using the same component unloaded Qs, can offer (very) slightly lower loss that a single L-network doing the same transformation. It's often assumed, incorrectly, that the fewer components, the better. Not true. --- On Thu, 9/20/12, ab2tc <[email protected]> wrote: From: ab2tc <[email protected]> Subject: Re: [Elecraft] KAT500 Remote Version To: [email protected] Date: Thursday, September 20, 2012, 4:58 PM Hi, That's not true. The L network's only solution is the lowest Q possible, meaning it will have the lowest tuner loss possible and the widest bandwidth. And if the capacitor and inductor steps are made small enough, a 1.0:1 solution is always possible. The fact that many tuners give up once the SWR is below 2.0 or 1.5 is merely a shortcoming in their tuning algorithms. I am having high hopes for the KAT500. Is anything known on how many bits of L and C resolution is there? AB2TC - Knut Wes Stewart wrote > What Don says is true as far as it goes. The L-network tuner has only one > solution, but it isn't necessarily a good one. > > Way back in 1998 when correspondence was via typewriter and snail mail, I > went around with Dean Straw, N6BV, then Editor of the ARRL Antenna Book, > about tuner losses. This was in conjunction with the editing of my paper, > "Balanced Transmission Lines in Current Amateur Practice" that appeared in > the Sixth Edition of the ARRL Antenna Compendium. > > Remarkably (coincidence I'm sure ;) it wasn't long before favored authors > were contributing articles to QST about how to measure tuner losses and > TLW was written. > > Tuner and line losses really do matter. > > Wes N7WS ______________________________________________________________ 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
