I need to come
up with a small antenna for a hand-held 40Mhz transmitter. I'd like to
use some sort of rubber duck helicoil to save space if poss.

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Plug a helical antenna into the output socket.

For 40 MHz, wind 140-150 close-wound turns of enamelled 18 gauge wire on a
0.4-inch diameter plastic or cardboard former. The turns will spread over a
length of about 8 inches.


Whether or not it works will depend on how far away is the receiver.


You can try matching the output impedance by sqeezing the box harder. How
many ohms is your hand + arm + torso + legs to ground?


For helicals of other dimensions download program HELICAL3 from website
below.
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Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
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