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Re: [TowerTalk] DRIVEN VERSUS PARASITIC 160 antenna

To: "TowerTalk" <>
Subject: Re: [TowerTalk] DRIVEN VERSUS PARASITIC 160 antenna
From: "Tim Makins" <>
Date: Wed, 4 Jan 2006 16:35:43 -0000
List-post: <>
----- Original Message ----- 
From: "Jim Lux" <>
Subject: Re: [TowerTalk] DRIVEN VERSUS PARASITIC 160 antenna

> There's an even easier way to control the length with air power.  Rather
> than a knife switch, make the switch a plunger switch inside the
> tube.  Imagine a tube with an air cylinder in the end, and the ram poking
> out. A short length of insulating tubing, and then the tubing for the top
> of the antenna.  The ram has one switch contact, and the bottom end of the
> top element piece has the other.  Extend the ram, and the two touch and
> connects the end to the bottom.  Retract the ram, and the top stinger is
> disconnected.
> This would also be a good way to use that liquid metal mentioned a few
> ago.  Rather than use the liquid metal to make the whole element, just use
> it as a switching element to bridge a gap.

Sounds like one of those tilt-switches from a pinball machine. They used
mercury to bridge two contacts. Trouble is, on a windy day, you might find
you were changing bands when you didn't want to...

73s Tim EI8IC
Ham Map Heaven. Free Stuff


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