Re: Antenna wire question for long spans

[zl1aih-2]

I'm sure Ron AC7AC will remember the 'safety link' - (maybe it had a
different name in the US Merchant Marine) but long wire antennas on
Commonwealth ships had a section at one end made of a short length
of the same wire as the antenna, but with two of the seven strands
removed.   This link had a slightly longer length of antenna wire
shackled across in a shallow "U", which in the event of a sudden
shock load the link would break but the antenna remained intact.
The spans were 500' or more, and were kept taut in order to support
the vertical "lead-in".   In heavy weather (head sea), the vessel could
shudder - almost ring, like a very large bell, and the masts would
shake violently.   Losing the main antenna in severe weather was no
trivial matter, especially if it dropped around the radar scanner.

Slightly off-topic, but relevant if you are using tree supports -
counterweights are the "belt", and safety links are the "braces"
(galouses -spelling? in the US). <G>
73,
Ken ZL1AIH (showing his age)
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[Ron D'Eau Claire-2]

We called them safety links too, or "break-away links". It's been 15 years
since I last hauled wire for a shipboard MF antenna but, if I recall
correctly, we used 5/16" dia. phosphor bronze wire rope for the antenna
wire. Heavy stuff. A typical length for an antenna might run a couple of
hundred pounds, but it withstood terrific punishment!

As a portside solder jockey I spent only a little time at sea, but the few
times I did go out and encountered heavy weather in the Pacific gave me
unending respect for all who spent much of their lives on "blue water".  

Ron AC7AC



-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of [hidden email]
Sent: Sunday, August 20, 2006 12:47 AM
To: [hidden email]
Subject: [Elecraft] Re: Antenna wire question for long spans


I'm sure Ron AC7AC will remember the 'safety link' - (maybe it had a
different name in the US Merchant Marine) but long wire antennas on
Commonwealth ships had a section at one end made of a short length
of the same wire as the antenna, but with two of the seven strands
removed.   This link had a slightly longer length of antenna wire
shackled across in a shallow "U", which in the event of a sudden
shock load the link would break but the antenna remained intact. The spans
were 500' or more, and were kept taut in order to support
the vertical "lead-in".   In heavy weather (head sea), the vessel could
shudder - almost ring, like a very large bell, and the masts would
shake violently.   Losing the main antenna in severe weather was no
trivial matter, especially if it dropped around the radar scanner.

Slightly off-topic, but relevant if you are using tree supports -
counterweights are the "belt", and safety links are the "braces"
(galouses -spelling? in the US). <G>
73,
Ken ZL1AIH (showing his age) _______________________________________________
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