Antennetuner (Danish Wikipedia)

Analysis of information sources in references of the Wikipedia article "Antennetuner" in Danish language version.

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docplayer.net

g3ynh.info

  • g3ynh.info: Impedance Matching. Part 1: Basic Principles. By David Knight G3YNH and Nigel Williams G3GFC Citat: "...The first point to note is that the target impedance, 50+j0 Ω, lies on the 50Ω constant resistance line. An initial impedance Z that does not lie on this line can always be brought on to it by moving it around a circle of constant conductance, i.e., by placing a reactance in parallel with it. An intermediate impedance that lies on this line can always be brought to 50+j0 by placing a reactance in series with it. Therefore impedance matching can always (in principle) be carried out in a two-step operation...If an initial impedance has a resistive component of less than 50Ω, it can always be manipulated onto the 20mS constant conductance circle by placing a reactance in series with it. An intermediate impedance that lies on the 20mS circle can then always be brought to 50+j0 by placing a reactance in parallel with it..."
  • g3ynh.info: Impedance Matching. Part 3: L-Network Solutions. By David Knight G3YNH Citat: "...The antenna (or arbitrary load) impedance matching problem can be solved (at least in principle) using only L-networks. Such networks naturally give rise to solutions that avoid excessive excursions in the Z-plane; which means that they are likely to be efficient in terms of power transfer. The L-network approach also involves only two variables for two unknowns. This means that it can be implemented in simple algorithms that are guaranteed to terminate; the termination criterion being obtained by using null-indicators for resistance [R], conductance [G] and phase (or reactance) [jX] [see 6.5]..."
  • g3ynh.info: Impedance Matching. Part 2: Popular Matching Networks. By David Knight G3YNH and Nigel Williams G3GFC Citat: "...In the following sections we show what happens in impedance space (i.e., in the Z-plane) when the various popular matching networks (antenna tuners) are adjusted...Many articles have appeared in the amateur radio press over the years alluding, without proper analysis, to the superiority of the π-match over other types of AMU, on account of its similarity to a low-pass filter...The foregoing hopefully illustrates the point that a π-match network should never be used without some kind of output indicator. Output level measurement moreover, will indicate maximum efficiency when the least possible amount of inductance is used consistent with keeping as far away as possible from the R=0 line...It should be stressed here, that the L-match is not a cut-down or restricted range version of the π-match. It is simply a better circuit, which is more difficult to mis-adjust, does not suffer from the unwanted residual capacitance of an unused capacitor, and is cheaper to build...T-match is a widely used network, favoured because it can match a given range of load impedances using smaller values of capacitance than are required for a π or L network. Detailed modelling of the circuit however shows that the price paid for using smaller components is a reduction in efficiency...The SPC transmatch remained the ARRL standard for many years after its introduction in 1981. The design was dropped by the 19th edition of the ARRL Antenna Book (2000) however, as a result of efficiency calculations...Ambiguity in the adjustment of an antenna tuner can be eliminated by the use of an RF measuring bridge giving null indications of R, jX, and G, provided that the matching network does not contain ganged matching elements...", backup

mdpi.com

practicalantennas.com

  • 14 January 2022, practicalantennas.com: antenna tuner efficiency and ratings Citat: "...First, the Unique Wire Tuner (the green Xs on the plot) almost always had the lowest losses of the group. For one thing, it is uses an “L” network, which theoretically will be the lowest loss configuration. But it also is configurable: I used 3 different arrangements of the components in matching this antenna, and two of them were the reverse of how it was designed to be used (due to the low impedances to be matched). Usually I was able to make a good guess what configuration to use based on the measured impedance, but swapping cables when changing bands is not particularly convenient...so, which tuner am I going to use? For the moment, probably the Unique Wire Tuner, and I’ll see if there is another configuration that does better on 30m....", backup

sandiego.edu

home.sandiego.edu

semanticscholar.org

pdfs.semanticscholar.org

web.archive.org

  • Old Wives' Tales In Amateur Radio. Chapter I: "An Antenna Tuner Does Absolutely Nothing Except Make The Transmitter Happy." by Cecil Moore, www.W5DXP.com, Rev. 1.5, Jan 9, 2014 Citat: "... The maximum power transfer theorem was first used with DC circuits. Given a source and a load, the theorem says that: Maximum power transfer will occur if the source resistance is equal to the load resistance. This is probably the origin of the myth that, for maximum power transfer to occur, an antenna must present a purely resistive, e.g. 50 ohm impedance, i.e. must be resonant... It seems to this author that since a tuner has the SAME effect no matter where it is located in a lossless system, and since a tuner must therefore necessarily have at least SOME effect no matter where it is located in a low-loss system, that an old wives' tale has bit the dust. In a low-loss antenna system, an antenna tuner in the shack indeed does have an effect on the power radiated by the antenna at the antenna..."
  • rfic.eecs.berkeley.edu: U.C. Berkeley, Prof. Ali M. Niknejad: Matching Networks Arkiveret 18. april 2017 hos Wayback Machine Citat: "...Consider the L-Matching networks, named due to the topology of the network. We shall see that one direction of the L-match boosts the load impedance (in series with load) whereas the other lowers the load impedance (in shunt with the load)..."
  • Tast eksempel input (Rsource) og output (Rload) ind og en frekvens på 1e7 (10MHz) - de kredsløb, som ikke understøtter impedans omsætning, skriver NaN (not a number); dvs ingen løsning: John Wetherell: Impedance Matching Network Designer. (Now with 16 networks!), backup
  • 14 January 2022, practicalantennas.com: antenna tuner efficiency and ratings Citat: "...First, the Unique Wire Tuner (the green Xs on the plot) almost always had the lowest losses of the group. For one thing, it is uses an “L” network, which theoretically will be the lowest loss configuration. But it also is configurable: I used 3 different arrangements of the components in matching this antenna, and two of them were the reverse of how it was designed to be used (due to the low impedances to be matched). Usually I was able to make a good guess what configuration to use based on the measured impedance, but swapping cables when changing bands is not particularly convenient...so, which tuner am I going to use? For the moment, probably the Unique Wire Tuner, and I’ll see if there is another configuration that does better on 30m....", backup
  • w5dxp.com: W5DXP's No-Tuner, All-HF-Band, Horizontal, Center-Fed Antenna Citat: "...The Ladder-Line Length Selector actually does tune the antenna system so no conventional "antenna tuner" is needed - no coils and no capacitors. Switches or relays (remote control) can be used for the switching function and should be sized according to the RF power levels involved...As one can see, the feedline losses average around one dB and the tuner losses are too small to matter..."
  • g3ynh.info: Impedance Matching. Part 2: Popular Matching Networks. By David Knight G3YNH and Nigel Williams G3GFC Citat: "...In the following sections we show what happens in impedance space (i.e., in the Z-plane) when the various popular matching networks (antenna tuners) are adjusted...Many articles have appeared in the amateur radio press over the years alluding, without proper analysis, to the superiority of the π-match over other types of AMU, on account of its similarity to a low-pass filter...The foregoing hopefully illustrates the point that a π-match network should never be used without some kind of output indicator. Output level measurement moreover, will indicate maximum efficiency when the least possible amount of inductance is used consistent with keeping as far away as possible from the R=0 line...It should be stressed here, that the L-match is not a cut-down or restricted range version of the π-match. It is simply a better circuit, which is more difficult to mis-adjust, does not suffer from the unwanted residual capacitance of an unused capacitor, and is cheaper to build...T-match is a widely used network, favoured because it can match a given range of load impedances using smaller values of capacitance than are required for a π or L network. Detailed modelling of the circuit however shows that the price paid for using smaller components is a reduction in efficiency...The SPC transmatch remained the ARRL standard for many years after its introduction in 1981. The design was dropped by the 19th edition of the ARRL Antenna Book (2000) however, as a result of efficiency calculations...Ambiguity in the adjustment of an antenna tuner can be eliminated by the use of an RF measuring bridge giving null indications of R, jX, and G, provided that the matching network does not contain ganged matching elements...", backup
  • semanticscholar.org: Wideband Tuning of Impedance Matching Networks using Hierarchical Genetic Algorithms for Multistandard Mobile Communications, backup
  • Design of a Broadband Electrical Impedance Matching Network for Piezoelectric Ultrasound Transducers Based on a Genetic Algorithm, backup Citat: "...transducer. A key feature of the new method is that it can optimize both the topology of the matching network and perform optimization on the components..."