Jacques:
I don't think Beverage construction is out-of-topic at all---quite the
contrary!
The most commonly available "ladder" line is the "450 ohm" window line. But
this line has single copperweld wires--high tensile strength but not very
tolerant of bending or kinking. However, both 450 ohm and 300 ohm window
line are available from the usual suppliers in stranded versions which are
easier to handle, etc. I use the narrower 300 ohm type for my two-wire
Beverages, because it is lighter. All that is required to use 300 ohm
instead of 450 ohm line is to change the turns ratio on the
differential-mode transformers--the single-ended impedance against ground is
unaffected.
The major problems encountered here are abrasion at the support points and
falling limbs. Supports along the run should allow the line to move freely;
having more frequent supports helps here. To simplify both end-supports and
splicing broken line, I purchased some 1/4" plexiglass sheet from a local
plastics store; I had the sheet cut into 2-inch strips at the store. At
home, I cut a pair of shallow grooves the length of each strip; the groove
separation matched the wire spacing of the window line. (A radial arm saw or
table saw facilitates these cuts.) The strips were then cut into short
lengths---4 to 6". A pair of these forms a sandwich with the window line
clamped in the middle. Compression is obtained by drilling holes for #8 or
#10 brass hardware in the plexiglass on either side of the window line. For
end clamps, one of the two pieces is made longer and has a hole for a rope.
These clamps and splices will not pull apart!
Such plastic can become less flexible and more brittle with age and weather,
but the clamps are so cheap and effective that their not lasting forever is
a minor problem.
Garry, NI6T
-----Original Message-----
From: topband-bounces@contesting.com
[mailto:topband-bounces@contesting.com]On Behalf Of Jacques RAMBAUD
Sent: Saturday, July 17, 2004 9:12 AM
To: topband@contesting.com
Subject: Topband: 450 ohms ladder line
Would like to use 450 Ohms ladder line for a 250 meters bidirectional long
beverage for 160m receving, What is the best choice, mechanically ,
electricaly and survival under winter conditions?
I have seen some from Universal radio inc .75 wide , some from the wireman
model 551, any other source or experience in the group ?
Weather here is mainly humid in winter very seldom snow, moderate wind, How
many years such lines can survive ?Thanks .
Since it is a bit out of the topic oh the list please answer direct to me
please : f6bki@wanadoo.fr
73
Jacques F6BKI
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