Erie Caboose Radio Antenna

Erie Caboose Radio Antenna

Postby Bernd » Thu Aug 24, 2017 9:31 am

I was contacted by TT forum member Al if I had any idea on how to make an antenna for an Erie caboose.

Link to Erie caboose: http://lists.railfan.net/erielackphoto.cgi?erielack-04-17-12/ERIE_C301_a_Berger_coll.jpg

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Considering the size that the antenna would be, .300" (7.62mm) in diameter and the size of wired needed, I figured a jig would be the best way. I don't think 3D printing would make the grade on this. We're talking .010" dia. wire being used here. Perhaps a brass part or plastic injection molding might work, but not for perhaps one piece, plus brass casting or injection molding is beyond home brew capabilities. So what to do? Well, a simple round jig will do.

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I'm going to employ a method called "Chain Mail" http://www.wikihow.com/Make-Chainmail

I started by making a mandrel approximately .200" (5.08mm) on one end and .300" (7.62mm) on the other. A small hole is drilled through the small dia. part to hold the .010" (.254mm) phosphor bronze wire.

Here's the procedure for making a coil close to .300" dia.

The mandrel is held in the lathe with the wire threaded through the hole in the jig.

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The lathe is turned on at a very low RPM, 2 or 3 rpm. The other end of the wire is held with a pair of plier's to give a tight wind on the mandrel. This is the way springs also made.

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Once the tension is release the wire un-winds some what. This is why a smaller dia. than .300" is used.

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Closer view of the spring/coils.

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Next the coiled wire is placed over the .300" dia. part of the jig to facilitate the cutting of a .300" dia. ring of wire.

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The end result is a ring close to the .300" dia. of the antenna.

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Now that I can make coils of wire to .300" dia. I will need a way to hold it to that dia. and also solder on 6 spokes, plus the pole through the center. I have an idea for a fixture to hold it all together and solder it. This will take a few days to develop and see if it will work.

Bernd
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Re: Erie Caboose Radio Antenna

Postby Richard-B » Fri Aug 25, 2017 1:35 am

...or an etched S-scale brake wheel ???
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Re: Erie Caboose Radio Antenna

Postby areibel » Fri Aug 25, 2017 7:01 am

I looked at several HO and S scale brake wheels but I couldn't find anything that was the right size, thin enough in cross section and had six equally spaced spokes. and with this being on the top where it's easily visible any EL modeler would pick up on that- the agony of being a rivet counter! If all else fails I may try that but when Bernd volunteered to help I was in!
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Re: Erie Caboose Radio Antenna

Postby Bernd » Fri Aug 25, 2017 8:13 pm

A progress report.

I drew up the antenna in my CAD program ran it through my G-code generator and engraved a piece of aluminum. Not pleased with the out come. This was the first time I tried using the CNC to mill a circle. I don't like the slightly out of round appearance. Would make for a poor looking antenna.

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Also kind of rough using both a "V" groove cutter and then a ball nose cutter.

So what next? Mill the top off to get a nice clean surface and try again.

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Time to try out the rotary table. I spend a few hours hand writing code. Dry ran the machine. Looks good. Not going to use a cutter this time. Going to try my carbide scriber I made for engraving the brass caboose walls. Won't get to it this weekend, but Monday is another day.

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Re: Erie Caboose Radio Antenna

Postby Bernd » Tue Aug 29, 2017 7:44 pm

Quick update. Tried out the rotary table. Gave a perfect circle, but the six legs of the antenna didn't seem to start at the exact center.

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Here's how big the jig is. That's a piece of .010" phosphor bronze wire. Once I get the six legs started from center I'll make some small clamps to hold everything together for soldering.

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That's it for now. Preparing for the last long weekend of the year. I'll be away from the internet while at camp. Should have internet next year.

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Re: Erie Caboose Radio Antenna

Postby areibel » Tue Aug 29, 2017 9:49 pm

Looking good Bernd!
I should have thought of your much earlier, it would have saved me a lot of headaches!
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Re: Erie Caboose Radio Antenna

Postby Bernd » Wed Aug 30, 2017 7:53 am

areibel wrote:Looking good Bernd!
I should have thought of your much earlier, it would have saved me a lot of headaches!
Al


Ah, that explains why I now have the headaches. :lol: Just kidding. I'm enjoying this challenge. I think I don't have the rotary table zeroed in right under the spindle. The best part of this will be when the engineering is done on the fixture I'll be able to crank out antenna's by the boxcar load. :dance: :wink: :grin:

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Re: Erie Caboose Radio Antenna

Postby Bernd » Wed Aug 30, 2017 10:36 am

Quick update on the antenna project. I got the rotary table zeroed in perfectly under the spindle center. It now produces a perfect jig.

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Next is developing the tiny clamps that will be needed to hold the wires down for soldering.

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Re: Erie Caboose Radio Antenna

Postby Richard-B » Wed Aug 30, 2017 11:07 pm

WOW!
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Re: Erie Caboose Radio Antenna

Postby Bernd » Thu Aug 31, 2017 8:01 am

Richard-B wrote:WOW!


Don't go "WOW" just yet. Wait till I have made the first antenna. :wink:

This has given me encouragement to try and make a locomotive spoked wheel. Or at least give it a try.

Won't get back to this project till next week. Going to the 1000 Islands for the holidays and won't be able to get on the net because of no connection. Hope to have one next year.

Everybody have a save holiday and pray for the folks in Texas.

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