Stacking cores can also help increase power handling capability without taking more pcb space (providing the core is flat on the pcb).
-- Alan wb6zqz -------------- Original message -------------- From: Larry Phipps <[EMAIL PROTECTED]> > A quick check shows that no small size cores will work for -43 material > with 10T at 1.8 MHz and 200W. However, FT50B cores come close, and are > fine at 3.5 MHz. FT50B is twice the thickness of the FT50A, and would > fit on the board because the thickness would only add height. > > 73, > Larry N8LP > > > > Linden, Mike (BRC-Hes) wrote: > > Larry, > > > > If you have the time, I'd certainly appreciate it if you'd run it > > through your spreadsheet for me. > > > > Thanks! -Michael > > > > ======================================================================== > > ====== > > > > You have a couple options. The flux density is higher, and therefore > > heating, with lower number of turns. They also go to a -43 mix (higher > > permeability) for the lower turns to keep the shunt reactance of the > > voltage xfmr high at 1.8 MHz. > > > > If you don't care about 1.8 MHz, you might be able to get by with 10 > > turns on the -61 cores... I would have to do the math. The other option > > is to stick with the -43 material, but get larger cores. I'm pretty sure > > they make the FT50A and FT50B (which are thicker) in -43 material, or > > you could go to a FT68 or FT82 if they'll fit. The best bet would > > probably be FT50A-43, since we know it would fit physically. I have a > > spreadsheet that I use that calculates these things for me... I can plug > > these in to see what would work if you like. > > > > 73, > > Larry N8LP > > > > > > Linden, Mike (BRC-Hes) wrote: > > > >> Does anyone know what modifications would need to be made to the CP1 > >> > > > > > >> Directional Coupler in order to get it to handle 200W at 20dB > >> attenuation? > >> > >> I'd like to use the CP1 as a cost effective means of extending the > >> useful range of my OHR WM-2 QRP Wattmeter, but 30dB is more > >> attenuation than I want and the power handling at 20dB is not high > >> > > enough. > > > >> Thanks, Michael N9BDF _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
