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Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062
interesting.
just a thought, but what about making your own gigantic ferrite rod using iron (III) oxide (easy to make using rust and a domestic oven) and boat epoxy? Not exactly hard to do but cheap and should work almost as well as a single ferrite rod.
maybe there's a use for all those otherwise useless cracked toroidal ferites from dead PC power supplies etc.
a nice source for flat inductors is old hp PSC's as they use four for EMC compliance purposes.
another interesting idea is to obtain a few hundred metres of flat cable used for PC hard drive connectors (there is a lot around now they switched to SATA) and connect alternating cores.
Registered Member #1721
Joined: Sat Sept 27 2008, 08:44PM
Location:
Posts: 136
Hello:
Yup you need a very long wire, a long time ago my friend had some luck by burying an old insulated Tesla coil as an antenna in his backyard. Now it was probably also related to some luck, but it worked at about 40KHz for almost a mile, to a receiver at another friends house. The trick was in somehow generating a ground wave. This is all from memory from a long time ago, but the guy who did this was quite brilliant and innovative. He used to piss us off by rubbing in that he was up to 18WPM!!! while we were struggling to reach 5WPM in code, this was in high school.
Hey just use the electrical grid connected to your house as a giant free antenna, via a nice capacitor / inductor to match it. (Just kidding really bad idea, meant as a joke only) The 9Khz would cause havoc all down the line if it had any power.
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Trying to transmit at 9 Khz
