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On Fri, 26 Dec 2003 20:08:07 +0000 (UTC), "Reg Edwards"
wrote: 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. =================================== 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. Thanks X.05, Reg. What do I use for a ground plane? -- "I expect history will be kind to me, since I intend to write it." - Winston Churchill |
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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. What do I use for a ground plane? =============================== YOU plus the box constitute the groundplane. Otherwise, for example, with a set of 4 1/4-wave radials you won't be handheld. --- Reg |
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On Sat, 27 Dec 2003 07:09:24 +0000 (UTC), "Reg Edwards"
wrote: 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. What do I use for a ground plane? =============================== YOU plus the box constitute the groundplane. Otherwise, for example, with a set of 4 1/4-wave radials you won't be handheld. Thanks Reg! You're a diamond. -- "I expect history will be kind to me, since I intend to write it." - Winston Churchill |
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