All of that heat is produced by RF heating the core instead of being radiated. It's all a matter of what you want to do with your RF :-)
One concern is the curie temperature - that temperature where the properties of the core change dramatically. In an antenna matching network (a.k.a. "tuner") the will cause the SWR seen by your Tx to change - often dramatically. 73, Ron AC7AC -----Original Message----- MFJ-902 tuner uses a single toroid with taps. The toroid becomes hot on some frequencies with 100W but survives. I guess losses are small compared to convenience of a very small unit. >From what I understand, the iron cores can have Q in excess of 300 if >they are below saturation. How much will they can handle depends on the load. A reactance of 300 will add a resistance loss of 1 Ohm, and a reactance of 3000 will add 100 Ohm. So the same toroid can handle KW with a longer vertical but could overheat at 100W with a short vertical. Ignacy ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
