[TenTec] RE: sterba

[Eric Scace K3NA]

   No, this is not a Sterba curtain.  Sterba curtains are substantially different in their feed arrangements and have poorer
performance characteristics that the driven dipole curtain in the photograph.

   The dipole curtain array also works much better than the rhombic on the railway ring that was described in earlier e-mails.

   Driven dipole curtains used by SW broadcasters can be built in wideband versions that can be used over as much as a 2:1 frequency
range (with some performance degradation due to beam splitting and power lost in some minor lobes).  The pattern can also be slewed
as much as plus/minus 30 degrees (again with some degradation in pattern) without rotating the array.  These systems have very
complex feed arrangements, in part because of the very high transmitter power levels in use.  Wideband curtain arrays also use a
reflector screen (many horizontal wires, spaced just a foot or so apart) -- another complex mechanical system to construct (keeping
all those wires in proper tension so as not to sag), maintain (requires people in bosun chairs) and support (very heavy wind loads,
especially if icing occurs).

   Deutsche Welle has an extensive antenna farm of curtain arrays at its transmitter site in Bavaria -- the largest that I've seen.

-- Eric K3NA

-----Original Message-----
From: tentec-bounces at contesting.com
[mailto:tentec-bounces at contesting.com]On Behalf Of Jim Reid
Sent: 2004 January 13 20:07
To: Rick at dj0ip.de; tentec at contesting.com
Subject: Re: [TenTec] RE: sterba



Subject: RE: [TenTec] RE: sterba


> Pour me one too, would ya, Tim?  Tnx - Rick

Is THIS a "sort of" sterba:

http://www.antenna.be/rhr.html   ?

73,  Jim  KH7M

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