Cecil, if I go back in time a long way, to the days of transformer
design, I recall that core loss increased as an exponential of
frequency. The exponential was greater than '1.2' and less than '2.0'.

Now, magnetic materials have changed, since the invention of the wheel,
but I still suspect that losses in magnetic materials are exponential,
even in new materials.

So, in a transformer I would expect core loss to increase exponentially
from 1.8 to 29.7 MHz.

In a balun, well I don't know!

Shortly after the invention of the wheel I came into the ownership of a
B&W air wound balun rated at 250 watts continuous that I used for over
35 years. I dumped it as part of the move from Massachusetts to New
Hampshire. That was DUMB! But, using air instead of magnetic material
certainly minimized losses grin.

Back to the Modern Age. How efficient is a transmission line
transformer? [TBD %] Can you quantify a suitable number or will it
remain a qualitative statement?

Deacon Dave, W1MCE
+ + +

W5DXP wrote:
Dave Shrader wrote:

Define 'Efficient' before you engage in this discussion.


OK, let's say as efficient as a transmission line transformer
over an entire range of frequencies. I don't think you will
find a normal transformer that is as efficient as a transmission
line transformer over the entire HF frequency range. But I could
be wrong.