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## [TowerTalk] network tuner losses

 To: [TowerTalk] network tuner losses cebik@utkux.utcc.utk.edu (L. B. Cebik) Wed, 17 Nov 1999 05:43:56 -0500 (EST)
 ```Network tuner losses can be roughly divided into two groups: 1. basic network losses, and 2. inadequate component losses. 1.Every network will show a loss factor (called "delta" by Terman) that is a function of the load to be matched vs. the input impedance. Not all loads--relative to the input impedance--permit low values of delta for any given network configuration. For the standard CLC Tee network, optimal matching conditions tend to coincide with maximum C values on the output side, even though there may be other settings that will effect the match. Even so, the delta may not be low in some cases, and the network itself will show losses even with the very best component quality. Some basic equations for estimating delta for various networks have been developed by ZL1LE. His equations and some basic notes on network losses are contained in a note at my site, and the equations are part of his network ATU program which is a part of the HAMCALC collection of utilities. These sources will help you estimate losses that are due solely to the conditions to be matched and the choice of networks to make the match. 2. Component losses represent inadequate values and designs of components that result in additional losses. Of course, if a given network design of a CLC tuner does not have adequate output capacitance range, an optimal setting for lowest delta cannot be found. However, even with sufficient range, components can be inadequately structured so that they dissipate additional power--or so that they fail to lose the heat generated and therefore begin to create destructive effects on the component or on other components in the immediate area. Basic coil and capacitor design play a major role in this set of losses, not to mention component sizing for the anticipated power level and range of deltas. However, one should not forget component cleanliness as a contributing factor to this class of losses. Switch construction and connecting wire sizes also make a difference. Tom Rauch's recent design that improves the structure of the coil for matching network use is an example of design upgrades that can make a difference in this department. Once one has designed all components of a network tuner to be fully adequate to the task at hand, there are still basic delta losses. For some matches, delta may be fractional and losses with high Q components can be less than 1%. (This is rare, and losses in the 2% to 5% range tend to be a practical minimum.) However, some loads may force very high values of delta, and losses will be much greater, even with the best components. The best solution is then to do one of two things: a. change the load to be matched so that a low value of delta is obtained, or b. change the network configuration to one that yields a lower value of delta for the matching situation. In many amateur installations, each option may be equally difficult to implement, so that living with delta losses may be necessary in the short run. In such cases, careful attention to component quality is a must. However, option b. becomes a live option if we decide that our present network tuner may have component shortcomings that we wish to correct with a new unit of commercial or home construction. I hope this helps a little in sorting the types of losses that occur with network tuners. -73- LB, W4RNL L. B. Cebik, W4RNL /\ /\ * / / / Tel: (423) 938-6335 1434 High Mesa Drive / \/ \/\ ----/\--- Knoxville, Tennessee /\ \ \ \ / / || / http://www.cebik.com 37938-4443 USA / \ \ \ \ || e-mail: cebik@utk.edu -- FAQ on WWW: http://www.contesting.com/towertalkfaq.html Submissions: towertalk@contesting.com Administrative requests: towertalk-REQUEST@contesting.com Problems: owner-towertalk@contesting.com Search: http://www.contesting.com/km9p/search.htm ```
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