[TowerTalk] Open Wire Spacers - Summary

[Bill Coleman AA4LR]

A week or two ago, when the merits of open wire line were discussed, I 
noted that the biggest impediment to using REAL open wire line is the 
requirement of fashioning spacers. Here's a summary of suggestions:

Material:

* Dowels boiled in Paraffin - (Not to mention the relative dangers of hot 
paraffin) this is a classic method. K7GCO indicates that these don't last 
long, and I would tend to agree. 

* Tongue Depressors - Another classic. K7GCO says they crack easily. 
Dowels would probably be a better choice.

* Delrin or Teflon Rod - I don't know where you get these, but it sounds 
good. 

* PVC - W8JI ran tests. Gray PVC hold water as it weathers - not 
recommended. White PVC is good, but gets brittle and cracks. Can fail 
when wet.

* Plexiglass - W8JI found it too brittle to work. Also failed when wet.

* UV Resistant Lexan - W8JI found it was best in his tests.

* Nylon - W8JI found it works OK.

* Ceramic - A classic, but they are very heavy and difficult to find.

* K3HX noted a QST hint (QST AUG 86) to use 120-size plastic film spools. 
Free for the asking at professional film houses.

Construction:

* N6NZ came up with a neat idea: Take flat plastic pieces and cut them in 
a stack:

+---------------+
|               |
|   |       |   |
+---+-------+---+

Slap two of these together on the wire in opposite direction, and hold 
together with cement, or use a UV resistant cable tie.

* My variation on N6NZ's idea: Cut slots on opposite sides

+---+-----------+
|   |           |
|           |   |
+-----------+---+

Cut slots slightly over center, then hold as above, or drill a hole in 
the center and hold together with a screw and nut (makes the spacers 
reusable)

* K6LL provided an excellent suggestion: use plastic coathangers for 
material. But the interesting idea was his construction technique. Set up 
a little drilling pattern, alternating little hole, big hole, little hole 
(o O o      o O o) in the straight pieces of the coathanger. Then, using 
a diagonal cutter, cut in the center of each big hole, which will leave a 
slot for the feedline wires. The
tie-wires go in the little holes. This method could easily be used with 
any type of plastic rod or narrow plastic sheet.

Thank you everyone for your suggestions! Lots of creative folks on the 
list.



Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@radio.org
Quote: "Boot, you transistorized tormentor! Boot!"
            -- Archibald Asparagus, VeggieTales


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