Fair-rite also states that multi-aperture ferrite cores (like this one) have greater bandwidth vs. a single-hole core made of the same material. I cannot explain that.
I can verify that the losses in any single-core transformer that I've ever made from that core, regardless of the Z ratio, was less than 1 dB. (0.9 dB was an extreme case.) And I've measured losses as low as 0.2 dB. ON4UN in his latest book wound transformers on that core with even less loss, IIRC. I used a stack of three once when I experimented with transmitting on a Beverage. Amazingly, the core never approached the Curie temperature even feeding it with 800 watts of CW and heavily processed SSB. Photos of that core test are at www.w0btu.com/files/misc/Binocular%20core%20power%20vs%20temp%20test/ . I cannot find the measured loss on that core at the moment, but it was certainly low enough (~0.4 dB, IIRC) that it never exceed 225 degrees F even with 850w key-down, with no air movement and a layer of heat shrink which reduced heat radiation. And I'm using that same transformer on the input of my swamped-grid amplifier. It barely gets warm even with 100w CW. My $0.02. 73, Mike www.w0btu.com On Fri, Nov 28, 2014 at 7:45 AM, Tom W8JI <[email protected]> wrote: > > ... This behavior makes a transformer broadband, ... > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
