Odds and EndsSome assorted side projects that have been interesting and/or useful. |
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| A small parts dryer. | |
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Parts Dryer
This is really pretty obvious, but I thought I'd toss it out as having been very useful from time to time. Hair dryers seem to accumulate faster than I can find places to put 'em to work. As soon as they start burping out a little asbestos, the wife gets all funny about using 'em, tho' they seem to work perfectly well for my purposes. I built this when I was learning clock-repair. Have since used it many times when I was in a hurry to get some part dry, either to continue with the project, or beat some agressive rusting. Image: 400x277k, 26k Ref: 299-5 |
| A homebuilt base antenna a'la Jim Weir | |
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From: Jim Weir Newsgroups: rec.aviation.homebuilt Subject: Re: base antenna for my handheld navcom Date: Mon, 27 Nov 2000 08:20:55 -0800 "Ken Mattsson" ->My problem is that my home is on low grounds and on top of
Just to "try it to see if it works" here is the cheapest,
dirtiest way to go. If you mount this on a mast and it works
well, then we can figure out some ways to make it better and
more weatherproof...
Get yourself a BNC female connector (UG-1094) and four ground
lugs that will fit onto the threads of the connector (Radio
Shack stuff). Remove the nut and lockwasher from the connector.
Get yourself two 22" (56cm) lengths of plain old "romex" #14
(1.6mm) house wire, or five 22" lengths of any #14 solid copper
wire. If you use the romex, strip five of the internal wires so
that you have 5 lengths of solid copper wire each 22" long.
Solder one end of each of four of the wires to a ground lug.
You will wind up with four lugs, each of which has a 22" wire
attached to it.
Solder the last wire to the center pin of the BNC connector.
(See last paragraph before beginning this step). Put the solder
lugs over the center wire and onto the threads of the connector.
Arrange them so that they are all at right angles to one
another. Fasten them down with the lockwasher and nut that came
with the connector.
The wire on the center pin of the connector is the "radiating
rod". With the radiating rod pointing up, droop each of the
four "ground plane" wires down at a 45° angle from the
horizontal.
Connect a BNC cable between your radio and this connector, and
away you go. In $US, this antenna costs about $1 to make
without scrounging too much stuff.
The problem with this antenna, of course, is that the elements
are rather flimsy. If you try it and it does your job, you may
wish to replace the soft copper wires with heavier wire, brass
tubing, or some other more rigid conductor.
(Before you tighten down the nut, you may wish to fabricate some
sort of bracket to hold the antenna to your mast. It really
shouldn't make a lot of difference whether or not the bracket is
made of metal or a nonconductor. The easiest way is to get a
piece of 0.050" (1.25mm) aluminum about an inch (2.5cm) wide and
a foot (30cm) long. Drill a 3/8" (9.5mm) hole at one end of the
strap, bend the other end into a 90° "L" shape, and use the
center nut and lockwasher to hold this strap along with the
ground lugs to the BNC connector threads.)
Jim
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Hole Layout in Brass Sheet
Rather than use lugs, I fashioned the attach for the ground plane wire into the mounting bracket, made from a piece of brass sheet. Image: 400x266, 18k Ref: 295-11 |
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Wires Soldered to Bracket
I used a propane torch to solder the wires into the bracket. Image: 400x266, 18k Ref: 299-17 |
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Tip Connection
A bit of sleeve from a crimp-connector was used to join the BNC and wire. Image: 400x266, 25k Ref: 299-15 |
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Assembly Complete
Here the BNC is mounted in the bracket, with the 'radiating wire' heading out the opposite direction from the ground plane wires. Image: 400x290, 23k Ref: 299-13 |
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Installed in Rafters
The ground plane wires are splayed out at 45-deg, and the bracket is screwed to one of the rafter diagonals. Reception is usefully better than the rubber-duck that came with the handheld radio. Cost -- about $12, mostly for the 12' BNC-terminated wire.
("Can it pick up Duluth?"; "Ah, my boy, it'll pick up Tierra del Fuego!" - Firesign Theatre)
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Send questions, suggestions, or other remarks to me (benton@siletzbay.com).
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