Holger: Your English is fine! Anything your internal KX3 ATU can match it will match with good efficiency.
Allow me a couple of observations that might help. Your assumption about low L is correct since, in any well made matching network, the greatest losses are when high circulating RF currents flow in inductors and result in resistance losses in the wire. In many modern miniature inductors using toroids, those currents can actually cause strong enough magnetic fields to "saturate" the torodial core, causing it to heat and consume more power. In the extreme, the core may crack. And heating the toroid may cause it to reach its Curie temperature where its magnetic properties change dramatically, which changes the inductance of the toroid. In operation, that may appear a a sudden large change in the SWR after transmitting for long enough to heat the core. "L-networks" such as Elecraft uses are very high efficiency matching networks. Other popular networks you will find used by Hams, such as the "T" network, may have wider matching capabilities but can produce very high losses as well. All passive elements, such as a coil, have some losses. So I avoid any extra elements that aren't necessary. If you are feeding your antenna wire directly - it is connected directly to the KX3 I'd not use an external coil unless the KX3 cannot find a decent match (by decent I mean 2:1 or lower). If you have a transmission line between the KX3 and the antenna you need to consider the losses in the transmission line, especially if it is a low-impedance line such as 50-ohm coaxial. If the transmission line is not terminated at the antenna in its characteristic impedance (e.g. 50 ohms for common coax) there will be standing waves on the transmission line. Those standing waves will produce areas of high currents flowing in the transmission line and result in losses due to resistance in the wires. In that case you can reduce the total losses by matching the transmission line to the antenna impedance at the antenna. The KX3 may be able to match the antenna, including the transmission line, to the KX3 but that won't reduce losses in a mis-matched transmission line. 73, Ron AC7AC -----Original Message----- From: Elecraft [mailto:[email protected]] On Behalf Of Holger Schurig Sent: Saturday, October 1, 2016 7:39 AM To: Fred Jensen Cc: <[email protected]> Subject: Re: [Elecraft] how to optimize end-fed? 2016-09-30 21:59 GMT+02:00 Fred Jensen <[email protected]>: > This is reminiscent of one of the five volumes in Douglas Adams' > trilogy, "The Hitchhikers Guide to the Galaxy." I understand that either my english is very weird. Or that I can't explain things good. But that you and Davidthink that they must make a 42 joke on this is definitely weird. The question was: I can query the KX3 ATU for what it settled. I have an end fed antenna and so I have various variables: - used tap (1:4, 1:9, 1:16) - some random length wire - band And forget an "optimal wire", I might just have switched from 12m to 10m. Or back. Depends on what I find, propagation ... so assume that my wire is just some random wire, not necessary optimal for the band. And also, in the context of my question, this is entirely irrelavant. I was never asking about wire lengths, this is easy to read up. Okay, back to my scenario: I just switched the new band. I'm not going to let my portable glass fiber down because of that and change the wire length! Instead I do what a lazy OM does: I press the TUNE button and the internal magical antenna tuner does it's job. It's actually so magic, that it will do it's job on all taps. On the 1:4 tap, on the 1:9 tap. And on the 1:16 tap. Woah! But I can query the ATU for what inductance and capacitance it used to do the match. And so my simple question was: would a lower inductance have less losses inside the ATU? And please: if you don't know the answer of if you think that there is no answer, than just stay silent. 73, Holger ______________________________________________________________ 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]
