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Old November 18th 10, 12:46 AM posted to rec.radio.amateur.antenna
amdx amdx is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 349
Default Matching antenna to crystal radio


"FCC per Anna Scarpetta" wrote in message
...
On Nov 15, 1:59 am, "amdx" wrote:
Hi Guys,
Assuming I have a tank circuit on a crystal radio with a Z at resonance of
1.5 megaohms.
How would I make an antenna and extract maximum signal and keep the Z at
750,000 ohms.


I did take part in the discussion of matching, but I am afraid you are
off by several orders of magnitude regarding the impedance value.

Hi FCC,
You have something wrong in your thinking, but tonight I'm not willing go
to far in
the description, Maybe tomorrow. We will use 240uh inductor and about 107pf
cap.
and assume a combined Q for the tank of 1000. and a parallel resonant
circuit.
The formula is 2 x pi x freq x L x Q. So at 1Mhz we have,
2 .x 3.14 x 1.000.000 x .00024 x 1000 = 1,507,200 ohms.
Look here http://www.crystal-radio.eu/engev.htm
There are more involved formulas, but this is close.
MikeK