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Spacers In Over / Under 75/40 Dipole




 
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Author Topic: Spacers In Over / Under 75/40 Dipole  (Read 382 times)
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W9ZSL
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« on: November 14, 2019, 12:54:05 PM »

I scored 10 NOS, still-wrapped Johnson ceramic spacers for @20. They're about 6" long by 1/2". I have a 75 meter inverted "V" that uses Copperweld wire. I want to add a second dipole for 40 beneath it, Any suggestions for some form of clamp, bushing or stay to keep the spacers in place?
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W1ITT
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« Reply #1 on: November 14, 2019, 03:09:42 PM »

There were a few different versions of the ceramic line spreaders and getting a matched set nowadays is a good prize.  Most of them had a shallow groove at or near the end, in addition to the hole.  The old buzzard method of making open wire line was not to thread the spacers onto the wires, but to lay them up against the groove and use a short tie wire through the hole and wrapped a few times around the main wire.  It was considered good practice to solder these connections.  That way, nothing can slip or slide and it all works well when airborne.  Using clips or other devices would add weight to the assembly and that's not what you want.

73 de Norm W1ITT
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KK4YY
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« Reply #2 on: November 14, 2019, 03:29:14 PM »

There were a few different versions of the ceramic line spreaders and getting a matched set nowadays is a good prize.  Most of them had a shallow groove at or near the end, in addition to the hole.  The old buzzard method of making open wire line was not to thread the spacers onto the wires, but to lay them up against the groove and use a short tie wire through the hole and wrapped a few times around the main wire.  It was considered good practice to solder these connections.  That way, nothing can slip or slide and it all works well when airborne.  Using clips or other devices would add weight to the assembly and that's not what you want.

73 de Norm W1ITT

From the "Handbook"...


* tie_wire.png (216.84 KB, 369x200 - viewed 83 times.)
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KA0HCP
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« Reply #3 on: November 14, 2019, 05:23:20 PM »

Use a somewhat heavy Solid wire for the tie-wire.
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New callsign KA0HCP, ex-KB4QAA.  Relocated to Kansas in April 2019.
Steve - K4HX
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« Reply #4 on: November 16, 2019, 06:02:52 PM »

How many spacers to you plan to use. Those ceramic spacers are quite a bit heavier than plastic ones.
 I used the plastic ones on a 80/40 meter dipole at my previous QTH. They were held in place with a dab of epoxy.



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