Hello all ..
I am currently building the following 1940’s ARRL
three-tube, superhet receiver;http://www.bignick.net/temp/arrl_1941_2.pdf
I was lucky enough to purchase some NOS Millen 1600 KC IF
Unfortunately, I thought that I was buying permeability tuned
coils, but they turned out to be air-core, and trim capacitor
tuned. (At least, the trim caps are “bread-slicers” and
not the cheaper compression type.)
Now, I read that the permeability tuned coils have steeper
bandwidth and more gain that the air-core variety :-(
My radio works fine, but it seems to lack sensitivity on the
80m ham bands.
The “religious” stations come thru blaring loud!
Have anyone had experience with air v.s. permeability tuned
Do they make a significant difference? Should I tear out
my way-cool 1930’s vintage transformers and replace them with
smaller “modern” 1600kHz permeability ones?
--Tom Nickel AKA KC9KEP