Topband: T-200 vs. T-300

[Tod - ID]

A couple rules for toroidal inductors might be useful. To increase the reactance you increase the number of turns -- the inductance goes up approximately the square of the number of turns. To increase the power handling capability you add additional cores to make a stack of cores. This will also help with the inductance since the toroid core AL value is affected by the cross sectional area of the core. 

I would expect that stacking cores might be the more economic route to the desired result.

If you are simply building a an RF choke to prevent feed line common mode RF current you should be using Type 31 material. For really good RF choking at 1.8 MHz you should plan on about six turns through at least five stacked cores of type 31 ferrite 2.4 inches 
o.d. [60 mm] Such a choke will have about 5000 ohms of impedance, mostly resistive. It will certainly handle 1.5 KW going through the feed line  [ if the feed line can handle the power].  See K9CY's online paper discussing such RF chokes. You may also want to check my web site for some measurements of various RF chokes made with type 31 using different numbers of cores and turns.

Tod, K0TO


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