[Amps] Iron Powder Core and Copper Wire Selection Data

[Dan Levin]

As part of Project Gamma ( http://www.k6if.com/ssamp/ ), the team has done a bit of work to understand how to design high power inductors for use in 1500 watt output filters, antenna tuners and the like.  We have put this information together onto one page, which can be found at http://www.k6if.com/ - follow the link to the page from there.  Hopefully this will save time and energy for others with the same questions.

If you find any errors on this page, please let me know so that we can correct it. 

Two interesting tidbits from our work:

1) T184-17 cores are _the_ solution for high power inductor design, if you need more inductance than a "0" material core can deliver.  Thanks for W3NQN for the pointer to these cores, which are available directly from Micrometals.

2) Because of the skin effect, at HF the current carrying copper volume (and thus current capacity) in copper wire goes up about 25% each time you move up to the next larger even size (i.e. 14 gauge wire can carry 25% more current then 16 gauge wire can).  Thus, as WM5Z pointed out, you are much better off winding two parallel wires (thus doubling your current capacity) than you are using a larger size wire (with its 25% improvement).  Two #16 wires or three #18 wires are enough to carry the 9 amps that results from a 3:1 SWR at 1500 watts - but one #14 isn't.

All our best wishes,

                         ***dan, K6IF

P.S.  We have two v1 harmonic output filter boards available for sale.  One is completely assembled and ready to drop into an amp, the other is a bare PCB (wth parts list and instructions).  The v1 filter is perfect for a 6 band 600-1000 watt solid state amplifier, or a low duty cycle 1500 watt amp.  Drop me an email if you are interested.