The Answer May Be : el-if-i-no :o)
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iane ~ RHF
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All are WELCOME and "Invited to Join" the
Shortwave Listener (SWL) Antenna eGroup on YAHOO !
<http://groups.yahoo.com/group/Shortwave-SWL-Antenna/>
SWL ANTENNAS GROUP => http://tinyurl.com/an6tw
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Some Say: On A Clear Day You Can See Forever.
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/502
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I BELIEVE: On A Clear Night . . .
You Can Hear Forever and Beyond, The BEYOND !
With a Shortwave Listener SWL Antenna of your own making.
"If You Build It {SWL Antenna} You Will Hear Them !"
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>For One and All,
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>Question - What Is... The Alpha Delta DX-SWL Sloper Antenna ?
>http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/5619
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>ABOUT - The Alpha Delta DX-SWL Sloper Antenna :
>http://www.alphadeltacom.com/pg7.htm
>http://members.tripod.com/~bpadula/sloper.html
>http://tinyurl.com/9cqzn
>http://www.universal-radio.com/catalog/sw_ant/0799.html
>http://www.universal-radio.com/catalog/sw_ant/0799om.html
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>Is it a true 'pure' Sloper Antenna ? - In a Word "NO" .
>First - There are those two "Iso-Res" Resonators
>aka : Loading Coils. http://www.rys.nl/addxswl_ii.htm
>DX-SWL => http://www.alphadeltacom.com/dxswl_ii.htm
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>Then - The SO-239 Jack Connecting and Mounting Point for
>the Coax Cable has both the Sloping Wire Antenna Element
>+plus+ the Vertical Down-Lead connected to it. Sort of
>Kind of 'like' a Dipole (Almost).
>http://www.rys.nl/addxswl_ii.htm
>http://www.alphadeltacom.com/dxswl_ii.htm
No, not like a dipole.
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>But - The Sloping Wire Antenna Element is 60 Feet Long and
>the Vertical Down Lead is only 30 Feet Long. So then it
>is more 'like' an Off-Center Fed Dipole or Windom Antenna.
>http://www.rys.nl/addxswl_ii.htm
>http://www.alphadeltacom.com/dxswlii.htm
The 30 foot section is supposed to act like a tower would in a
'classic' sloper configuration.
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>Next - We have the 16 Foot {Matching} Stub as an added feature.
>http://www.rys.nl/addxswl_ii.htm
>http://www.alphadeltacom.com/dxswlii.htm
Not a matching stub, read the manual and you see that while they call
it a stub it is attached to the center conductor and is listed as the
element for 16 - 21 meter bands.
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>Plus - It is Sloped at about a 75* Sloping Angle vice 45*.
>http://www.rys.nl/addxswl_ii.htm
>http://www.alphadeltacom.com/dxswl_ii.htm
It is sloped at whatever angle the user can manage, though the manual
states 20 - 40 feet with 25 feet being 'best overall'. Haven't
bothered to figure out the angle as regardless of what the manual says
- users will install based on what they can accomplish at their
location.
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>Finally - The Antenna is configured more 'like' a Top-Fed
>Lazy "7" {Seven-on-it's-Side} and uses a Coax Cable as the
>Feed-in-Line to the Radio/Receivers.
>http://www.rys.nl/addxswl_ii.htm
>http://www.alphadeltacom.com/dxswl_ii.htm
Well I have to give you this one.
>So the Question Remains :
>What Is... The Alpha Delta DX-SWL Sloper Antenna ?
>http://www.rys.nl/addxswl_ii.htm
>http://www.alphadeltacom.com/dxswl_ii.htm
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A commercially made wire antenna that is, in my estimation, a bit
overpriced - like all other commercially made wire antennas - but it
does what is claims. I've used their shortened version and in A/B
comparison to an end-fed wire of similar length and similar
orientation (note 'similar' not 'same') it was overall no better and
no worse. If you feel the need to 'categorize' what it is then call
it a hybrid trapped sloper - though AD might be upset for referring to
their 'ISO-RES' coils as traps.
>For One and All,
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If I was buying a storebought antenna, I'd probably consider this one:
Barker & Williamson "BWD-90" T2FD Antenna provides full coverage
of the Shortwave Bands from 1.8 MHz to 30 MHz and is 90 Feet long.
http://www.bwantennas.com/ama/fdipole.ama.htm
http://www.universal-radio.com/catalog/hamwire/0872.html
Idealy at 90 Feet long this "BWD-90" T2FD Antenna would
require a 64 Feet elevation difference between the Tip-Ends
of the Antenna.
Practically speaking the BWD-90 T2FD Antenna at 90 Feet long
would only need a 45 Feet elevation difference between the
Tip-Ends of the Antenna. This would require a High Mounting
Rigging Point of 60 Feet and a Low Mounting Rigging Point of
15 Feet.
iane ~ RHF
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>For One and All,
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Whatever it is, I had one in the early 1990s, connected to an NRD 525
receiver. Excellent reception at just about any frequency.
It's built like a tank; heavy wire; well put together; should stay up
in rugged climates.
It is sorta "visible" tho' with all the coils and things. Not a
stealth antenna.
Bob
k5qwg
Steve