
A Tunable Liquid Metal Antennas for Tuning in to Anything - jonbaer
http://spectrum.ieee.org/tech-talk/consumer-electronics/portable-devices/a-tunable-liquid-metal-antenna-increases-the-frequency-range-of-communication-devices-
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jhallenworld
Cool.. but can I make a home version of this for ham radio? I'm thinking of
plastic tube from home depot + some kind of liquid metal and a pump.

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VLM
If you allow moving parts may as well use a stepp-ir company antenna.

For a blast from the past google "electrochemical hour meter" or try:

[http://globalepower.com/media/Coulometers-
OBSOLETE.pdf](http://globalepower.com/media/Coulometers-OBSOLETE.pdf)

So... say you have a tube of mercury and tiny electrolyte gap, then shove DC
power thru it, and the mercury electroplates into one side. Takes thousands of
hours per inch. That makes them great hour-meters for engines or whatever.
Why, in only a year you could tune a dipole from one end of 20 meter band to
the other LOL.

I would imagine the end load capacitance might be a bit high, and the voltage
limit being a bit low... But its an idea.

They stopped selling those around the time they stopped selling things like
mercury tilt switches, for some odd reason.

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deutronium
Heh, I was just about to post about mercury coulometers, I bought a number
recently to play with (I had a silly idea of trying to make a watch with them)

I connected one to 500V, and you could see lots of bubbles forming in the gap
between the mercury.

Krasnow has a nice video of them
[https://www.youtube.com/watch?v=Cxj399LuX1M](https://www.youtube.com/watch?v=Cxj399LuX1M)
showing a view of them through a microscope

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morcheeba
Aw, that's an awesome idea! Why didn't it work?

Some quick math... To get the bubble to go across a 2400 hour meter in 24
hours, you'd have to run at 100x12v = 1200 volts. I guess it wasn't stable at
500v?

Also, no idea how the current/voltage scales, but normally this is .72mW ...
at 100x it's still 72mW -- not too bad.

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deutronium
It may still work, but I managed to break the coulometer with some mercury
leaking out, when trying to prise open the casing, to get a better view under
my microscope.

I'm going to try again with another one soon :)

One thing I'm worrying about though, is if the higher voltage causes the
mercury to get to a temperature that leads to the glass breaking under heat.

