Rule number 34 for antennas:

Don't try to evaluate an antenna on one one or two stations. Leave it up and
use it over a period of days or weeks. Every antenna has it's strengths and
weaknesses which leads to rule number 35 ... you can never have enough antennas
!

jw
wb9uai
milwaukee

ASW,

What you are missing is the Matching Transformer between the Antenna
Element and your Coax Cable.

NOTE: Before your buy or build a MW/SW Matching Transformer try using
a simple TV 300 to 75 Ohm Matching Transformer to "Test" your Antenna
Set-Up.

1. The Far-End of the "Speaker Wire" Antenna Element is Stripped,
Twisted Together and Soldered. Then Sealed with Electrical Tape.

2. The Near-End of the "Speaker Wire" Antenna Element is Stripped and
Connected to the Primary #9 Side of the Matching Transformer. Then
Sealed with Electrical Tape.

3. The Secondary #1 Side of the Matching Transformer is Connected to
the Coax Cable. One Lead to the Center Conductor Wire and the other
Lead to the Coax Shield Wires.
- - - At this "Junction" the the Coax Cable's Shield should be
Grounded to a good Earht Grounding Point. (Ground Rod and Short Heavy
Thick Ground Wire.)

4. The Coax Cable runs from the Antenna Element to the
Radio/Receiver. A second Grounding Point should be used at the
Radio/Receiver


FWIW: You have now 'created' a "Closed Loop" (Thin, Flat and
Elongated) Antenna Element (Balanced) that Matched-Up-To a Un-balanced
Coax Cable with a Remote (Quite) Grounding Point. For the most part
this is a Low Noise Antenna design.


OBTW: For more SWL Antenna Ideas . . .
- - - Check-Out the SWL Antennas and AM & FM Antennas eGroup on YAHOO
!

GoTo= http://groups.yahoo.com/group/SWL-AM-FM-Antenna/


iane ~ RHF
..
..
= = = "ASW"
= = = wrote in message igy.com...

*sigh*

well that did not seem to work.
I am being blown out by my local AM station.
But I am still pretty dead on all the other AM stations.
I cannot pick more than say 3 or so.
Before it was about the same.

But I all I seem to have done is increase the noise!

I have some spurious interference every 60-70 Khz.
This is from my power I am assuming.
How do I get rid of it?

I have it hooked up to about 50 foot of speaker wire.

Which is in turn soldered to the center lead on my coax.
The coax then goes into my reciever.
Am I missing something?

Thanks!


..

ASW wrote:

I have alread about 50 feet of 50 Ohm RG-6 for the lead in.

RG-6 is 75-ohm cable, but no need to worry.

Art N2AH

Harris wrote:

ASW wrote:

I have alread about 50 feet of 50 Ohm RG-6 for the lead in.

RG-6 is 75-ohm cable, but no need to worry.

Art N2AH

I use R6U coax made for satellite TV systems. I has good shielding and
works well as the lead wire for my low noise inverted-L (Doty-L)
antenna. R6U coax is 75-0hm and the radio (R8B) has a 50-ohm antenna
input but the mismatch hardly matters for shortwave receiving.


-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
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could some one explain what An impedance matching transformer is and how i
could make one?

thanks
charles foster

"chuck" wrote:

could some one explain what An impedance matching transformer is and how
i
could make one?

A random wire antenna fed at one end will present a high impedance (~2000
ohms). Most coaxial cables have a characteristic impedance of 50 or 75 ohms.
To match the coax to the antenna, a matching transformer is used.

See.
http://www.hard-core-dx.com/nordicdx...eed/index.html


Or do a Google search on: "9:1 balun"

Art Harris N2AH

CF,

I Am Glad You Asked )

B A L U N - R E A D I N G - L I S T - (First Draft):

The BALUN Defined:

"A balun is a device that joins a balanced line (one that has two
conductors, with equal currents in opposite directions, such as a
twisted pair cable) to an unbalanced line (one that has just one
conductor and a ground, such as a coaxial cable). A balun is a type of
transformer: it's used to convert an unbalanced signal to a balanced
one or vice versa. Baluns isolate a transmission line and provide a
balanced output. A typical use for a balun is in a television antenna.
The term is derived by combining balanced and unbalanced."
http://searchnetworking.techtarget.c...342213,00.html

"Baluns and ununs (unbalanced-to-unbalanced transformers) belong to a
class of matching devices known as transmission line transformers.
They transmit the energy from input to output by a transmission line
mode instead of by flux linkages as in the case of conventional
transformers. When properly designed, they can have extremely high
efficiencies and very broad bandwidths. The theory of operation of
these devices rests chiefly on that of chokes and transmission lines.
A balun or unun is simply a choke that isolates the input from the
output (thus only allowing transmission currents to flow) and a
configuration of transmission lines."
http://www.coilws.com/W2FMI.htm

Balun Explained (WTH is a Balun) by G4NSJ
http://www.g4nsj.co.uk/balun.shtml

The Purpose for a Balun by John Doty
"The purpose of a balun is to block common mode waves (current flowing
in the same direction on both conductors of a transmission line) and
pass differential mode waves (current flowing in opposite directions
on the conductors)."
http://www.hard-core-dx.com/nordicdx...ed/balun3.html

Matching Less Important for Reception - by John Doty
http://www.hard-core-dx.com/nordicdx...ed/balun5.html

A Review of the ICE Model 180 Beverage/Longwire Matching Unit
- - - by John Doty
http://www.anarc.org/naswa/badx/ante...ing_xfrmr.html

Low Noise Antenna - by John Doty
http://www.anarc.org/naswa/badx/ante...e_antenna.html

Grounding is Key to Good Reception - by John Doty
http://www.anarc.org/naswa/badx/antennas/grounding.html

Balun Measurements
http://www.radioworks.com/nbalmeas.html

Experiments on Remote Receiving Loops by Lyle Koehler [KØLR]
(Using a Balun with a LW/LF Loop Antenna)
http://members.aol.com/lwcanews/longwave/lf-loops.htm

Fabricating Impedance Transformers for Receiving Antennas
- - - May 2001 by Paul Bryant
http://members.aol.com/DXerCapeCod/z_transformers.pdf

Balun Core and Winding Methods
http://www.catchnet.com.au/~rjandusimports/tut_11b.html

Construction and Use of Broadband Transformers
http://www.oselectronics.com/downloa...ansformers.pdf

Winding Your Own Transformers
http://www2.hard-core-dx.com/nordicd...ansformer.html

TRANSMITTER-RATED TOROIDAL BALUN KITS,
TOROIDS & ENAMELLED WIRE PACKS
http://www.ozgear.com.au/balun/ToroidalBalunKits.htm

Binocular Cores vs Toroidal Cores
http://lists.contesting.com/archives.../msg00001.html

RFI - Ferrites - Baluns - Iron Powder
http://www.sadona.com/news/news5.html

Baluns and Common Mode Noise Isolation
http://www.w8ji.com/common-mode_noise.htm

Doug's Antenna Transformer Page
Antenna Transformer Construction and Testing
http://users.netonecom.net/~swordman/Radio/unun.htm

Transmission Line Transformers "THEORY"
http://www.bytemark.com/products/tlttheory.htm

RF Transformers by Mini-Circuits
http://www.minicircuits.com/appnote/tran14-2.pdf

1:1 Balun
http://www.qsl.net/iz7ath/web/02_bre.../pag09_eng.htm

4:1 TRANSMISSION LINE BALUN
http://www.qsl.net/iz7ath/web/02_bre.../pag10_eng.htm

4:1 balun for 160 to 10 meters
http://www.hard-core-dx.com/nordicdx.../4_1balun.html

Putting a Balun and a Tuner Together - by Kevin Schmidt [W9CF]
http://fermi.la.asu.edu/w9cf/articles/balun/

4:1 QRP Balun by C. C. (Clay) Wynn N4AOX
http://kg8ih.cit.cwru.edu/w8edu/proj...ynn-balun.html

W2FMI Transmission Line Transformers (BalUns & UnUns)
- - - by Jerry Sevick
http://www.coilws.com/W2FMI.htm

Homebrew a 4 To 1 Balun - by Mike Martell [N1HFX]
http://www.rason.org/Projects/balun/balun.htm

Beverage Matching/Tuning/Balun - by Mauno Ritola
http://dallas.hard-core-dx.com/archi.../msg02536.html

The Loaded Dog 1:1 Antenna Balun
http://www.geocities.com/the_loaded_.../project1.html

The BALUN - by Ian C. Purdie [VK2TIP]
http://my.integritynet.com.au/purdic/baluns.htm

The Choke Balun at Electronics Tutorials
http://www.electronics-tutorials.com...hoke-balun.htm

Toridal Balun Winding - by W8JI
http://www.w8ji.com/toroid_balun_winding.htm

Balun and Core Selection - by W8JI
http://www.w8ji.com/core_selection.htm

HOW TO Construct a Guanella Balun - by Ralph Holland [VK1BRH]
(A Cost Effective Current-Mode 1:4 Balun)
http://www.arising.com.au/people/Hol...h/CM4Balun.htm

Impedance Matching Transformer (IMT) - by Paul Ormandy [NZRDXL]
http://radiodx.com/spdxr/Baluns.htm

Baluns, Earth and More… - by Paul Ormandy [NZRDXL]
http://radiodx.com/spdxr/Some_Important_Aerial.html

Impedance Matching Transformers for Receiving Antennas
at Medium and Lower Shortwave Frequencies
June 2003 by Bill Bowers, John Bryant and Nick Hall-Patch [VE7DXR]
http://radiodx.com/spdxr/media/imt_doc1.doc

Magnetic Longwire Balun (MLB) Palomar
http://www.palomar-engineers.com/MLB-1/mlb-1.html

MLB for DX-Antennas - by "VK3KCG" Australia
http://dxantennas.com/wst_page4.php

The Magnetic Longwire Balun (MLB)
= = = A "CON" or Not ?
http://www.hard-core-dx.com/nordicdx...d/magbal1.html

The Complete Answer to your Interference Problem
the "LWC System" for Long Wire Antennas
http://ourworld.compuserve.com/homep...kit/lwcsys.htm

W1CG - Balun Kit
http://www.njqrp.org/balun/


iane ~ RHF
..
..
= = = "chuck"
= = = wrote in message ...
could some one explain what An impedance matching transformer is and how i
could make one?

thanks
charles foster

..