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Old March 21st 06, 07:23 PM posted to rec.radio.shortwave
Telamon
 
Posts: n/a
Default TWISTED terminated folded dipole

In article .com,
"N9NEO" wrote:

Yes, you are right Mark. Thanks for pointing this out. Not really
sure where my math error is. I've become way too dependant on mathcad
to do all my thinking for me. Looks like just a brainfart - only had
to move the decimal over 6 places.

Not sure where the 25nH came from, should have just been 5nH/t
5mH *(1/1000) * (1/1000)

So that 8 turns should have been 5*8*8 or 320nH. Two cores stacked
makes 640nH.

Maybe just j36 ohms at 9mc then.

In either case I think it's getting to be time for a balun tweak.
Ladder is up near attic hatch so don't have to climb two floors I got
nice big #43 cores at work that my boss gave me. I can probably set it
up to run ok on 20m.


I think the impedance of that antenna is depended on the centered
termination resistor at 600 ohms. There is also a 1/4 wave transformer
section. This is from memory I didn't look it up. Since this being used
fro receiving and not transmitting where you are trying to use the
antenna fro a load I would not bother with the termination resistor or
impedance transformation section of the antenna design and just use it
as a basic loop antenna. The impedance of the loop will be somewhere in
the 50 to 100 ohm range so you don't need a transformer.

--
Telamon
Ventura, California