John,
Edmund Laport's book "Radio Antenna Engineering" contains many photos of
professionally installed large curtain arrays. Figure 3.104 shows the rigging
methods used to connect the feeder to the dipoles.
I use similar methods for the four full size 80 meter 2 element quads suspended
from my 200 foot towers. I use three strand AWG 12 copperweld wire (often
called "Rhombic Wire") for the loops and open wire feeders. My rigging methods
are identical to those shown in the Laport book.
A free digital copy of the book can be downloaded at:
http://www.lulu.com/items/volume_3/159000/159004/1/print/RadioAntennaEngineering-lulu.pdf
73
Frank
W3LPL
---- Original message ----
>Date: Sun, 1 Mar 2009 08:10:30 -0800
>From: "Dan Hearn" <n5ar@air-pipe.com>
>Subject: Re: [TowerTalk] Professional HF curtain arrays
>To: "John E. Cleeve" <g3jvc@jcleeve.idps.co.uk>, <towertalk@contesting.com>
>
>John: I was faced with a similar problem in handling the gamma match wire
>connection to a horizontal arm on my 131 ft crankup tower. I was concerned
>that the flexing of the wire would ultimately cause a break at that point.
>My solution was to connect the wire to a small egg insulator. The other end
>of the insulator used a short length of dachron rope to the arm. A strip of
>flat beryllium copper spring material bridged across the insulator and rope.
>providing electrical continuity. I have had no problem with this in 8 years.
>I think the same thing would work with Quad antenna wires.
>73, Dan, N5AR
>
>----- Original Message -----
>From: "John E. Cleeve" <g3jvc@jcleeve.idps.co.uk>
>To: <towertalk@contesting.com>
>Sent: Sunday, March 01, 2009 5:03 AM
>Subject: [TowerTalk] Professional HF curtain arrays
>
>
>> Good afternoon,
>>
>>
>>
>> I wonder, are there any in the group with professional experience of
>> erecting the wire curtain arrays, suspended between tall towers, as used
>> at
>> professional SW BC stations? If there are, then may I ask what method is
>> used to connect the feeders to the antenna elements, in order to eliminate
>> any "flexing" movement between the two, caused by varying wind pressure,
>> which may then lead to metal fatigue and fractures and failure?
>>
>>
>>
>> I have trawled through all the information I can find, in books and on the
>> internet, but without success. I can only think that the entire wire
>> curtain
>> array must be suspended under such tension, that it must behave as a rigid
>> structure. I would be grateful if any of the group can supply the answer.
>> A
>> link to an appropriate text book would be much appreciated. 73, John.
>> G3JVC
>>
>> _______________________________________________
>>
>>
>>
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