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Old November 2nd 05, 10:35 AM
RHF
 
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Default Simple 'build-it-yourself' Shortwave Listener (SWL) Antenna made from TV Parts - [Was : On Topic]

Cuhulin,

Consider a simple 'build-it-yourself' Shortwave Listener
(SWL) Antenna made from TV Parts.
http://groups.yahoo.com/group/Shortw...a/message/6233

SWL ANTENNA PARTS - BUY THE FOLLOWING :

* 40 - 100 Foot Piece of TV 'type' 300 Ohm Twin Lead.
RadioShack Catalog # 15-1174
http://cgi.ebay.com/_W0QQitemZ5825567843
[ Speaker Wire (24 AWG) or Landscaping Cable (16 AWG)
could also be used here for the Wire Antenna Element. ]

* 300 Ohm to 75 Ohm Matching Transformer.
RadioShack Catalog # 15-1230
http://cgi.ebay.com/_W0QQitemZ5764013531
http://cgi.ebay.com/_W0QQitemZ5824268873
[ Shortwave Longwire Antenna Balun Match 9:1 # SWLZ -or-
Shortwave Longwire Antenna Balun Match 9:1 # LMZ-75 made
by RF Junkie could be used with a Single Wire Antenna
Element instead by simply connecting the Two Wires
together at both ends. ]
http://cgi.ebay.com/_W0QQitemZ5823838982
http://cgi.ebay.com/_W0QQitemZ5825174432

* 25 - 100 Foot piece of 75 Ohm RG6 Quad-Shield Coax Cable.
RadioShack Catalog # 15-1579 = 25 Foot Coax Cable
RadioShack Catalog # 15-1572 = 50 Foot Coax Cable
http://cgi.ebay.com/_W0QQitemZ5824932152
http://cgi.ebay.com/_W0QQitemZ5791766267

* One 2" Hose Clamp

* One Roll of Nylon-Poly Mason Line

* Some Electrical Tape and Plastic Wire Ties.


ASSEMBLYING THE SWL ANTENNA PIECES :

* Take one end of the Twin Lead and Strip-Off about
1 Inch of the Insulation and Twist the Two Wires Together
and Solder them; then Bend the Twin Lead back on itself
about 6 - 8 Inches and Wrap it with Electrical Tape and
Secure it with Plastic Ties. This is now your Far-End
of the Wire Antenna Element.

* Take the other end of the Twin Lead and Strip-Off
about 1 Inch of the Insulation. Then take the TV Matching
Transformer and Twist the Two Wires Together and Strip-Off
about 1 Inch of the Insulation. Twist one Twin Lead Wire
with one TV Matching Transformer Wire; and then Twist the
other Twin Lead Wire with the other TV Matching Transformer
Wire. Solder both sets of Twisted Wires, and wrap the
joints with Electrical Tape. This is now your Near-End
of the Wire Antenna Element with the Matching Transformer
attached.

* Connect one end of the Coax Cable using the "F" Connector
to the "F" Connector-End of the Matching Transformer.


RIGGING THE SWL ANTENNA :

* Find an OutSide Metal Cold Water Pipe going into the
Ground that is under near some structure / object that
can be used as a support for the Wire Antenna Element.
[ A Roof, the Eaves, a Tree, whatever; anything that
is 8-12 foot High or Higher to Rig the Wire Antenna
Element to that will keep it at least 8 Feet overhead. ]

* Take a Brillo / Steel Wool Pad and clean an area about
2 Inches wide around the Metal Pipe.

* Place the Matching Transformer with the "F" Connector
on the bottom along side the Metal Pipe. Use the Hose
Clamp to Secure the Metal "F" Connector to the Metal Pipe
and get a good Metal to Metal Electrical Connection.
This is your Antenna Ground.

* Take the Wire Antenna Element and attach some Mason Line
and Rig it to the First Antenna Support at/near the House;
and Secure it in place.

* Take the Far-End of the Wire Antenna Element and walk
stretch it to the point on the ground; where you Second
Antenna Support is located overhead. [ A Tree, Pole,
Fence, whatever; anything that is 8-12 foot High or Higher
to Rig the Wire Antenna Element to that will keep it at
least 8 Feet overhead. ]

* If there is going to be some left over Wire Antenna
Element; then Coil it up in about a 6 Inch Diameter Coil
with even and tight Turns and secure it with 5-6 Plastic
Wire Ties.

* Now attach some Mason Line and Rig the Far-End of the
Wire Antenna Element to the Second Antenna Support; and
Secure it in Place

* Then Adjust the Rigging of both Antenna Supports so that
the Wire Antenna Element is Tight and at least 8 Foot above
ground level. Use a Weight at the Far-End with the Mason
Line to allow for normal movement and loading of the Wire
Antenna Element.

* Finally run/route the Coax cable into your Radio Shack
and Connect it with the appropriate "F" Connector to ____
Adapter to your 'portable' AM/FM Shortwave Radio or Table
Top Shortwave Receiver as needed.
For Shortwave Receivers using a SO-239 Jack
for the SWL Antenna Input :
* * "F" Connector [Adapter] to SO-239 Connector
RadioShack Catalog # 278-258
* * For 'portable' AM/FM Shortwave Radios using a
1/8" Mono Phone Jack for the SWL Antenna Input :
* "F" Connector [Adapter] to 1/8" Mono Phone Plug
RadioShack Catalog # 278-257
* * Right-Angle "F" Adapter
RadioShack Catalog # 278-305
* * "F" Jack to Mini-Phone Plug Adapter
RadioShack Catalog # 278-267


I DON"T KNOW WHY THIS SWL ANTENNA WORKS :
But for some reason using about a Hundred Feet (100') of
Twin Lead or Speaker Wire seems to Cancel-Out a lot of the
local RFI / ENF Noise and yet still produces a fairly good
level of RF Signal for most Shortwave Radio/Receivers.
Think of it is a very long and very thin Loop Antenna.


CAUTION - You should have a Safety Ground for your Radio
Shack that is Bonded to your House's Electrical System.


hope this helps - iane ~ RHF