TWISTEDHED IS MY HERO!!!!

"N9NEO" wrote in message
ups.com...
Antenna is up and working. Took me and daughter's boyfriend about 3
hours to build and install into attic. It ended up being almost 40
feet long with about 13" spreaders. This works out to be about 8mc. I
think.

For the Balun I wound 4 turns for the coax end and 8 turns for the
antenna end. I put them on a pair of Amidon FT114-67 cores I had.

Al = 5mH/1000t so 25nH/t
1.6uh for 8 turns
90 ohms at 9mc

oops, I think 3.2uH cause I stacked two cores. This works out to
about 180 ohms at around 9mc. I suppose a few more turns would be ok
since antanna impedance is 300 ohms. I think the rule of thumb is to
keep transformer reactance a few times the circuit impedance. I'm not
exactly sure how the number of turns effects the signal. For transmit
I know I would use enough turns or stack lots of cores to keep
magnetizing flux low to keep cores from overheating.

Anyway, TWISTED terminated folded dipole seems to be working nicely.
It is quieter than my verticle or dipoles. Good call.

regards,
Bob
N9NEO