That is a nice LOOP kit and it is for MW or for AM radio broadcast,
not SW.

Yea you can copy that very easy, make an X frame with 2' sides, wrap
some wire (magnet, insulated, almost any really) around it to a AIR
Capacitor and you have a tunable passive loop. Here is a GOOD BASIC
LOOP LINK:

http://www.mindspring.com/~loop_antenna/

You can copy his design exactly. The kit you talk of saves you from
scrounging for all the parts. There are not that many parts, but if
you don't have it you have to get it. THE DESIGN IS 100 YEARS OLD, no
state secret.

You can make an untuned LOOP with out the capacitor. I just made one
out of a 1' x 1' pizza box and about 22' of wire, no capacitor. It
works well for my needs, to bring in a few near by AM stations. The
radio in question has no internal loop or loop-stick so I needed
something. It probably came with an untuned loop, no doubt that I
lost. Here is a link to the ultimate AM antenna and a pic of one I
built like it (I went 5 turns because I had the wire):

http://members.cox.net/rwagoner/columns/am_antenna.html

Here is my last post of thread on this antenna with pictures:
http://groups.yahoo.com/group/loopantennas/message/5333


HOW DOES IT (tuned passive loops) WORK. The best explanation is a
swinging pendulum held in you hand. For a given weight hanging off a
string of given length, if you move your hand back and forth at a
certain rate (frequency) the weight at the end will react in a given
way. If you get the rate of hand moving back and forth just right
(for the string length & weight) it will swing wide (resonance). If
you move your hand back and forth faster or slower, the pendulum will
not move as vigorously or with regular movement. If you increase or
decrease the weight or length of string, it will react differently to
different freq of hand movement. SO WHAT DOES THAT HAVE TO DO WITH A
LOOP. Well the input or hand movement is the radio signal
(frequency). The string length is the length of the loop, and the
weight is the CAPACITOR! If you get the length of loop (number of
wraps around a frame of X circumference) and capacitor (weight at end
of string) just right for a given radio freq (hand movement) you get
the most resonance.

If you google LOOP antenna you will find web links for calculating
the range of "resonance" for a given loop, size, number of turns and
capacitor (capacitance) range.

The kit in question, if you varnish it and take your time will be
nice to look at and listen to. Like all passive loops, you have to
aim them and tune them. Of course you can make your own for cheaper.
The most expensive part is the air capacitor which is about $15-$20.

Cheers George

--- In loopantennas@yahoogroups.com, "Adam E." <gccradioscience@...>
wrote:
>
>
> That sounds pretty hard, oops, my mistake, I got the wrong one.
Ok
> let me explain, there is a shortwave loop antenna that I want to
plan
> on building soon a company called MTM Scientific made and they sell
it
> as a kit and I wanted to learn more about how to build one with
> readably available parts .   I saw this kit and I thought it would
be
> fun to build since there is a frame and wire and other parts and
> pieces.  If not possible I guess I will have to buy this kit soon.
I
> am still considering getting myself a copy of the JJ Carrs Loop
> Antenna Handbook for me to study when I am bored.  Thanks for the
> help,  its really appreciated.
>
> link:  http://www.mtmscientific.com/swloop.html
>
> Adam E.
> Virginia Beach VA
>
> SWL Radios: Grundig YB-400PE, G5, Mini 300, S-350DL, FR-200.  Radio
> Shack DX-380, 390, 392, 398.  RY-611 and CF-1888
>
>
>
>
>
>
> --- In loopantennas@yahoogroups.com, Chris Trask <christrask@>
wrote:
> >
> > >
> > > >
> > > > > Sorry but there is no link there except a Spanish forum that
> does not
> > > > > have any instructions in building a SW loop antenna.   If
> anyone else
> > > > > can help that would be greatly appreciated thanks.
> > > > >
> > > > >
> > > > > Adam E.
> > > >
> > > > Adam; I agree with Jim. What do you want to build? ... untuned
> passive
> > > > loop?  active loop?  tuned passive loop?  resonant cut
loop/folded
> > > > dipole?
> > >
> > >
> > > Tuned passive loop for to hang around by the window.
> > >
> >
> >      A wideband tuned passive loop will be very difficult to
> implement as the impedance of the loop will vary significantly.  For
> instance, a 1 meter diameter loop consisting of 1 turn of 1/4"
> diameter copper tubing will have a resistance of about 0.5 ohms at
> 4MHz, 10 ohms at 12MHz, and then increases to 420 ohms at 15MHz.
It's
> parallel resonance is around 17.9MHz.  With a 4:1 BalUn transformer,
> such an antenna can be easily used for the 25M SWBC band without an
> amplifier.
> >
> >      I went through months of building and testing loops of
various
> diamters, turns, and conductor diameters for my 2-part series on
> active loops in the Jul/Aug and Sep/Oct 2003 issues of QEX.
> >
> >
> >
> >
> >
> > Chris
> >
> >      ,----------------------.       High Performance Mixers and
> >     /    What's all this     \    Amplifiers for RF Communications
> >    / extinct stuff, anyhow?  /
> >    \  _______,--------------'           Chris Trask / N7ZWY
> >   _ |/                                  Principal Engineer
> >  oo\                                  Sonoran Radio Research
> > (__)\       _                             P.O. Box 25240
> >   \  \    .'  `.                     Tempe, Arizona 85285-5240
> >    \  \  /      \
> >     \  '"        \                 IEEE Senior Member #40274515
> >      .       (  ) \
> >       '-| )__| :.  \              Email: christrask@
> >         | |  | | \  '.
http://www.home.earthlink.net/~christrask
> >        c__; c__;  '-..'>.__
> >
> >                        Graphics by Loek Frederiks
> >
>

If you have a link relevant to the group, please post it in the Links section.
If you just put it in a message, it will get lost in the shuffle after a few
days. The coverage of the list is pretty broad.

All members can upload Links, Files, and Photos.

A few guidelines:

Try to place them in the proper folder, if it exists. If not, you can either
just put it in the root folder and eventually I'll move it into the proper
place, or create a folder.

When creating a folder or uploading a file or photo, please don't use spaces or
punctuation. You can either use caps for the first letter of each word, or use
underscore as a space.

Like this: "4x8Loop" or "4x8_loop" or "Steves_4x8_Loop"

Not like this: "Steve's 4 x 8 Loop." That goes for Folder names and File names.

A special note about the Photos section: Although it will allow arbitrarily
large images, it will only show them to the moderator and whoever uploaded them.
Everyone else can only see a resampled max of 300x400 pixels. So anything over
that in Photos is a waste of storage. So crop in to the important parts and
resample to about 300x400. For photos, JPG saves smaller and looks better, for
line drawings GIF is smaller and looks better. If you need to post a schematic
diagram that would be unreadable at 300x400, I strongly suggest the Files
section as it has no such limitations.

Feel free to ask if you need help figuring out how to crop and resample.
Irfanview is a fairly easy to use program that loads just about any file, you
can crop and resample from there: http://www.irfanview.com

Or for more complex stuff, another free program is GIMP: http://www.gimp.org

A last note: if you see something in any folder or in the messages that looks
like spam or simply inappropriate, don't post on the list- email me directly and
tell me about it and I'll take care of it with a minimum of fuss.
loopantennas-owner@yahoogroups.com

Thanks,
Steve Greenfield

Amplifiers for Antennas and Pre-Selectors
http://members.cts.com/king/j/jlkolb/site/ant.htm
- presented by John Kolb [KK6IL]

Four(4) Schmatic Diagrams are provided:

* The KRS AA-1 Active Antenna was sold through Radio West
in the early '70's, and was a good performer.
http://members.cts.com/king/j/jlkolb/site/aa-1.pdf

* In the '70's, this Circuit was developed suitable for
use as an Antenna Pre-Amplifier or as the Amplifier for
a Box Loop Antenna or Ferrite Rod Antenna.
http://members.cts.com/king/j/jlkolb/site/fet_pre.pdf

* A fancier version, with a Dual-Gate FET, featuring an
RF Gain Control. Dual-Gate FET's can still be found,
but not easily. This Schematic is closely related to
a Pre-Selector sold as the KS Pre-Selector.
http://members.cts.com/king/j/jlkolb/site/dual_fet.pdf

* Better Nulling is obtained with a Loop Antenna when it
is Center Tapped and Amplified with a Balanced Amplifier.
http://members.cts.com/king/j/jlkolb/site/dif_fet.pdf


Justice AM Antenna With Twin Coil Ferrite
Justice AM Antenna With Twin Coil Ferrite by C. Crane Co.
http://www.ccrane.com/justice_antenna.asp

Directional Terminated MW/LW Loop by WellBroook (UK)
K9AY is the Remote Controlled Variable Termination; Provides a Cardioid
Reception Pattern with up to 30dB Gain Front-to-Back; Uses Two Delta Loops.
http://www.wellbrook.uk.com/K9AY.html

Kiwa - High Performance MW Air-Core Loop Antenna
High Performance MW Air-Core Loop Antenna by KIWA
http://www.kiwa.com/kiwaloop.html

Palomar Engineers Loop Antennas LW-MW-SW2
Palomar’s Loop Antenna gives superb performance on the AM medium-wave broadcast
band. The loop rotates and tilts to give deep nulls so you can eliminate local
interference. It also allows you to null out a station and listen to another one
on the same frequency.
http://www.palomar-engineers.com/Loop_Antenna/loop_antenna.html

Q-Stick+
The Quantum Stick Plus+ by DX-Tools Ferrite Rod Antenna Tuner Coupler
http://www.dx-tools.com/QStick.htm

Quantum QX Loop and other DX-Tools Products
The Quantum QX Loop 7.5" Ferrite Rod Antenna Plus 40 dB FET Amp
http://www.dx-tools.com/PRODUCTS.htm

Terk AM loop at Amazon.com
Here is a place you can buy yourself a TERK AM loop antenna, even some other
stuff that is kind of off topic to talk about. 73
http://www.amazon.com/exec/obidos/ASIN/B000069EUW/qid=1075080062/sr=2-1/ref=sr_2\
_1/102-8712984-4397719

WL1030 by maartenhagg
Wideband Magnetic Loop 10kHz - 30MHz
http://home.hetnet.nl/~maartenmiriam/index.html


C Crane Company
They sell the Justice AM Loop Antenna, Select A Tenna, Terk AM 1000
http://www.ccrane.com

Kiwa Electronics
Kwia makes the best products for you and your radio equipment, and also improves
things that needed improvement a long time ago.
http://www.kiwa.com

Stormwise Ferrite Rods
Get some huge ferrite rods and a converter to go along with its, heck it even
comes with project book.
http://www.stormwise.com

Universal Radio Company
They sell all sorts of loops big and small for LW/MW/SW and VLF also 10 kHz to
15 MHz
http://www.rffun.com


ALA-1530
Find the best UK LF/MF antenna here.
http://www.wellbrook.uk.com/

AOR
This is the site that sells the AOR loop
http://www.aorja.com/ant-e.html

Kiwa Electronics
The maker of the air core loop antenna and other useful items that you may want
on your wish list.
http://www.kiwa.com

LF Engineering Company
A group of engineers, who make products for VLF/LF listening even ELF loops!
http://www.lfengineering.com

Select A Tenna by Intensitronics Corp
The maker of the select A tenna, a great AM loop antenna that is a little bigger
than the terk
http://www.selectatenna.com

Terk Technolegies
The maker of the best sold AM and I use also called the AM-1000 AM loop antenna,
there is also technical information on how it works.
http://www.terk.com

Torus Tuner Loop Company
A very specially made loop that is almost as big as a hula hoop
http://www.torustuner.com


GRAHN (Germany) Specialized Loop Antennas for MW and SW Reception Contributed by
radiohighfreq
Grahn offers both Ferrite Rod Antennas and Shielded Loop Antennas. Translated
from the Gremany Language Webpages here is the "Grahn Specialized Loop Antennas
for MW and SW Reception" ULR Address: http://www.grahn-spezialantennen.de/
  Use the Google Translate a web Page Tool http://www.google.com/language_tools
to convert these webpages to English.
http://makeashorterlink.com/?Z5F025FE4


When considering AM Loop Antennas . . .
- - - It all comes down to Time? & Money?

How much Time? Are you going to be 'using' the Loop Antenna for
DXing or simply for "Better" AM Radio Reception (Sports/Talk Radio
Loop).

How Much Money? Are you willing to spend for a Loop Antenna to get
the kind of better reception you want.

TBL: Time and Money translates to the AM Loop Antenna's Value to You.


The average radio listener (97%), who wants better AM Radio
Reception, can spend $100 or less and get an AM Loop Antenna that
meets their needs.

Here is a brief list of the more common AM Loop Antennas for $100 or
less.

* Justice AM Loop Antenna (Active)
- - - http://www.ccrane.com/justice_antenna.asp

* Torus Tuner 27" Loop Antenna (Passive)
- - - http://www.torustuner.com/

* Select-A-Tenna Model #541M (Passive)
- - - http://www.selectatenna.com/

* Terk AM Advantage Loop Antenna (Passive)
- - - http://www.terk.com/pdfs/Advantage.pdf

* RadioShack AM Loop Antanna # 15-1853 (Passive)
- - - Discontinued (Find 'used' on eBay)

* MTM Scientific AM Radio Loop Antenna (Passive)
* http://www.mtmscientific.com/loop.html
- - - Starter Kit, Deluxe Kit or Finished Antenna!

* * * Home made 'Box' AM Loop Antennas
- Usually 20" to 24" in size
- - Generally a simple Passive antenna
- - - Can be made Active with an add-on amplifier


#1. * Justice AM Loop Antenna (Active)
> - - - http://www.ccrane.com/justice_antenna.asp
>

#2. * Torus Tuner 27" Loop Antenna (Passive)
> - - - http://www.torustuner.com/
>

#3. * Select-A-Tenna Model #541M (Passive)
> - - - http://www.selectatenna.com/
>

#4. * Terk AM Advantage Loop Antenna (Passive)
> - - - http://www.terk.com/pdfs/Advantage.pdf
>

#5. * RadioShack AM Loop Antanna # 15-1853 (Passive)
> - - - Discontinued (Find 'used' on eBay)


>
> * MTM Scientific AM Radio Loop Antenna (Passive)
> * http://www.mtmscientific.com/loop.html
> - - - Starter Kit, Deluxe Kit or Finished Antenna!
>
> * * * Home made 'Box' AM Loop Antennas
> - Usually 20" to 24" in size
> - - Generally a simple Passive antenna
> - - - Can be made Active with an add-on amplifier
>
>
> NOTE: Beyond $100 in the $200 to $400 range are the
>

#1.a. Kiwa MW Air Loop Antenna

#1.b. Quantum Loop Antennas

. . . #3. Palomar Loop Antenna


Basic Wire Back Yard Loop Antennas
Full-wave loops are very popular antennas. They are especially useful on 80 and
40 meters where they perform well at modest heights. These are closed loops that
are one full wavelength long. Horizontal loops may be fed at any convenient
spot. For best performance, make your horizontal loop into a square, especially
if it is to be used on several bands.
http://www.radioworks.com/nloop.html

K9AY: How to Build the K9AY Loop Receiving Antenna
AY Technologies Antennas by K9AY. Excellent Antenna for Medium Wave Frequency
DXing.
http://www.aytechnologies.com/Products/products.htm

Plumbers's Loop Antenna {Broad-Band 'Single' Turn}
A 'different' twist on the "Broad-Band " (4.8MHZ to 24.5MHZ) Loop Antenna using
a Single Turn of Copper Tubing within a Plastic Hula Hoop and a Variable
Capacitor *All-in-One-Unit* + Photos + Schematic + Loop Pre-Amplifier ~
Presented by Nicolae Santean
http://www.csd.uwo.ca/~nic/radio/radio.shtml

Six Foot Square by Six Turn Loop Antenna
New Mid-Size Loop Antenna by Graham Maynard with Matching Balanced Amplifier:
Frequency Range 50KHz - 5000KHz.
http://www.mitedu.freeserve.co.uk/Circuits/RF/6x6loop.htm

Ten Foot Receiveing Loop for Low-Frequency DXing
A Page out of VE7SL's Note Book. This 10 Ft. Air-Core Receiving Loop was
originally designed and constructed for NDB DXing and now is used for LOWFER DX
work.
http://www.imagenisp.ca/jsm/loop.html


Dave's HomeMade Loop Antennas
This is the loop antenna my dad built in 1958. Although I was only 8 years old
at the time, I knew what this was for and how it worked. WebSite/Pages produced
by Dave Schmarder Page Contributed by radiohighfreq
http://www.schmarder.com/radios/misc-stuff/loops.htm

Kowalski AM/MW Loop Antenna
The Kowalski Loop is similar to the Radio West Loop in that it is an amplified
ferrite rod type loop. It only tunes the medium wave band. It was built and sold
on a very limited basis by former National Radio Club member Paul Kowalski.
Presented by Robert Kramer NV8V
http://members.aol.com/RKDX/Kowalski-Loop.html

Radio West LW/MW Loop Antenna
Radio West Loop Antenna was the commercially available Low (LW) and Medium
AM/MW) Frequency Antenna available. It was a improvement over the Space Magnet
Loop Antenna, which was the rage among medium wave DXers in the early-mid 70's.
Presented by Robert Kramer NV8V
http://members.aol.com/RKDX/Radio-West.html

VEA MW-1812 Loop Antenna Users Guide
High Performance Tunable Loop Antenna VEA MW-1812VE
http://www.dobe.com/vea/Loops/1812Guide/index.htm


18-inch Box Loop for MW
Relatively easy-to-build MW loop that is small enough to fit on a desk, yet
large enough to accommodate radios the size of a Sangean ATS-803A or smaller.
For best nulling, place antenna/radio combination on a turntable/platter.
http://www.clearsail.net/~n5wbi/radio/PonderLoop.html

4 Foot Box loop antenna
Heres a 4 foot loop project by Bruce
http://www.mindspring.com/~brucec/loop2.htm

ATL-3 Loop Antenna by Graham Maynard (UK)
Loop & Amp Project: ATL-3 Loop Windings are in the Shape of a Five 26" Sided
Spiral
http://www.mitedu.freeserve.co.uk/Circuits/RF/atl3.htm

Alt-Azimuth Wooden "HOOP LOOP" Antenna by Linus
The Great Pumpkin" Speaks on "How To Make" a Loop Antenna from a Wooden
Embroidery Hoop. Read the Exciting Saga of his journey in to the Kingdom of
Hooppy-Looppy-Dom presented by RadioIntel.Com.
http://www.radiointel.com/anthooploop.htm

DX zones results on loop antennas and projects
Reference links on some loop antenna projects for you to build
http://www.dxzone.com/catalog/Technical_Reference/Antennas/Loop/

DXers Tool Box - DIY - Tuned Loop Antenna
The DXers Tool Box "How To Build" a Tuned Loop Antenna = How can you vastly
improve your Medium Wave reception? The antenna consists of an LC (tuning)
circuit formed by the air-core loop and a tuning capacitor.
http://www.geocities.com/SunsetStrip/Underground/8585/loop.html

Embrodary Loops
While these loop are for crafts, they can be a craft of art for improved AM
radio reception!
http://www.craftking.com/crafthtml/embroidery_loops.htm

Hard Core DXing
Here's what nordic dx has to offer in their discription of loops in this website
http://www.hard-core-dx.com/nordicdx/antenna/loop/index.html

K5DKZ - Three Foot Box Loop Antenna Kit
Complete Parts and Plans for a 3 Ft Box Loop Antenna "Kit" ~$85+SH
http://www.qsl.net/k5dkz/4loop.html

KIT -by- MTM Scientific, Inc. -for- AM Radio DX Loop Antenna
KIT =//= Designed to Build an AM/MW Radio DX Loop Antenna =//= Offered by MTM
Scientific =//= Deluxe Loop Antenna Kit: Includes ALL the Hardware for Building
this AM/MW Radio DX Loop Antenna.
http://www.mtmscientific.com/loop.html

Long LoopStick Antenna for MW DXing
Wound on a Three (3) Foot Length of PVC pipe, the "Long LoopStick Antenna" was
an experiment to try to improve AM radio reception without using a long wire or
ground.
http://ourworld.compuserve.com/homepages/Bill_Bowden/page2.htm

TL Loop Receiving Antenna 10 KHz - 30 MHz
The principle of operation is that an rf voltage appears across the terminals of
a loop when it is placed in an electromagnetic field. The voltage is
proportional to frequency for a given field strength and so at Very Low
Frequencies the voltage is very small and requires greater amplification but it
is not quite as simple as that. The new TL Loop uses a unique feedback system to
optimise the amplification/noise factor over a much wider range than has been
possible hitherto.
http://ecforster.netfirms.com/LpAnt/Doc1.html

Very Low Frequency (VLF) Up-Converter
STORMWISE: Palomar VLF Converter allows you to use your ordinary ShortWave Radio
to listen below the AM Broadcast Band. Directly Tune VLF Stations of 10 KHz to
500 KHz using your existing ShortWave Radio. The VLF Converter easily connects
between the Antenna and the Radio.
http://www.stormwise.com/vlfconv.htm


W2BRI Xmit Loops Contributed by n3hkn
Ham Radio xmitting loops. Detailed plans and reports from Hams experiences.
Typical cost is $50 for pipe, capacitor, motor.
http://www.standpipe.com/w2bri/index.htm


WHY? Use a Shielded Loop Antenna?
Read Message #384 and learn about the Shielded Loop Antenna's - Gain -
Directivity - Apparent Gain due to Directivity - Noise - Noise Reduction -
written by Brian Greer aka "progman22000" ~ (GreerTech.Com)
http://www.greertech.com/hfloop/mymagloop.html

"AM Loop Antenna Calculator" - by Bruce Carter
Here is a Great Tool for those Loop Antenna => "What Ifs...."
http://www.mindspring.com/~loop_antenna/amloop_calc4.htm

"Loop Antennas 101" Read This First
Minnesota DX Club's Loop Antenna's web page that is a 'Must Read' =Says It All=
A Starting Point Class 101- - - TOPICS: Principles of the Loop Antenna - What is
a Loop and Why Use It - Construction Principles - What Can I Use a Loop For -
Loops Another Look - Pictures of Home Built PVC loops - Loop Links
http://www.frontiernet.net/~jadale/Loop.htm

* NEW => 2002 AM Loop Antenna Construction "Tips" by Bruce Carter
Introduction / Why Another Loop Antenna Page? / Mathematics of Rectangular Loop
Antennas / Construction Articles / Loop Antenna (and Related) Links
http://www.mindspring.com/~loop_antenna/

Loop Antenna Modeling Software and more...
Original, high-quality, radio engineering/modelling programs. Not freeware --
just free gifts -- please help yourself -- no catch. Download in a few seconds
-- not zipped-up -- run immediately -- user friendly. Presented by R.J.Edwards
(G4FGQ) Software
http://www.btinternet.com/~g4fgq.regp/page3.html

Loop Antennas at Hard Core DX
TABLE: Number of Turns -v- Size of Loop in the Middle of this webpage.
http://www.hard-core-dx.com/nordicdx/antenna/loop/amloop.html

Loops and Rods =&= The Ferrite Rod Antenna
Theory / Formulas / Drawings = The use of a small Magnetic Loop as an antenna.
The ferrite has the effect of intensifying the magnetic field inside the loop.
http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/RadCom/part7/page5.html

Modify the common AM Radio Loop Antenna
Hard-Core DX & Nordic DX = Topics: Install Larger Ferrite Rod - Fix External
Antenna -Add a Long Wire - Or a Loop - Construct it - Connect it - Add an
Amplifier. Presented by Bruce Carter
http://www.hard-core-dx.com/nordicdx/antenna/loop/amloop.html

Sensitivity of Multi Turn Receiving Loops
LWCA - Multi turn wire loops are often used as low frequency receiving antennas.
Basic electromagnetic theory is developed here as it relates to electrically
small multi-turn loops at low frequencies. - Presented by William E. Payne,
N4YWK
http://www.lwca.org/library/articles/ywk/looptheo.htm

Using the Small Loop Antenna by Joe Carr
DXing.Com presents Joe Carr's Radio Tech Notes: Eight Page PDF Document provided
by Universal-Radio.Com
http://www.dxing.com/tnotes/tnote09.pdf


How to Get Better AM Radio Reception
Features Loop Antennas and much more. The Antenna is 90% of Your Radio. Still
Need More Signal? Try a Better Antenna.
http://geocities.com/SunsetStrip/Towers/3332/amradio.html

Introduction to Broadcast Band AM/BCB/MW DXing
The International Radio Club of America (IRCA) WebPages
http://www.geocities.com/Heartland/5792/bcbdx.htm


** Radio-Antenna-PRO ** H.Hertz-Forum
Remember you may need some Russian Text software for this groupThe international
forum for radioengineers, scientists and hams. All about radioelectronics,
radiocommunications, radiophysics, electrodynamics. About 250 members from 20
countries. In Russian language. Very active. Lot of interesting researches and
discussions.
http://groups.yahoo.com/group/Hz/

AM Radio Listening
This is the group for the AM radio DXer, who wants to post logs and talk about
loop antennas for AM only
http://groups.yahoo.com/group/amradiolistening

Longwave Radio Listening
This group is dedicated to members that are into longwave radio listening and
transmitting
http://groups.yahoo.com/group/longwaveradiolistening/

Magnetic Loop - German web site focuses on SW Loop Antennas. Contributed by
radiohighfreq
Posting are in German and English. Claims to be Non-Commercial and Pop-Up Add
Free.
http://www.magnetic-loop.de/main.html

Radio DX World
This groups cares about you and your DXing, and also can help you with many
resources of DX. Its by a radio group called the Global Communications
Commission that devotes the hobby of radio DXing
http://groups.yahoo.com/group/RadioDxWorld/

Radio DXing with The Interference Problem
This is great for that annoying problem you have with your loop antenna, and you
may think its the loop, think again it could be that messed up street light,
next doors dimmer switch, and other something else you can't probably solve with
just a loop antenna.
http://groups.yahoo.com/group/RadioDx/

Radio Science Observing
Are you curious like Art Bell,and into radio phenomica, and propagation heres
the place to come and join.
http://groups.yahoo.com/group/radioscience/?yguid=74346996


"3805er" 80-Meter balanced coax loop
Small shielded rx only loop for 80 meters
http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/3805er.ht\
m

Low Noise Coax-Shielded Faraday Loop Antennas for 80 - 40 Meters
Four interesting and nice looking Shielded SW Loop Antenna webpages: * Low Noise
Coax-Shielded Faraday Loop Antennas for 80 - 40 Meters * Coax-Shielded Faraday
Loop Antennas Research Notes * Schematic of Coax-Shielded Faraday Loop Antennas
- Website presented by "ProgMan22000" (GreerTech.Com)
http://www.greertech.com/hfloop/mymagloop.html

Magnetic Loop Antennas Receiving - by W8JI
This WebPage's Topic Are: - Small Receiving Loops - Loop Antenna Fields - Dipole
Antenna Fields - Radiation - Loop Shielding and Balance - by W8JI
http://www.w8ji.com/magnetic_receiving_loops.htm

OctoLoop Antenna (Shielded)
LWCA - The "OctoLoop" stands out in performance and ease of construction.
Description and Drawing of the OctoLoop Antenna - Presented by William E. Payne,
N4YWK
http://www.lwca.org/library/articles/ywk/octoloop.htm

Radiation and Fields (Magnetic Loop Antennas) - by W8JI
This WebPage's Topic Are: - Electric Field - Magnetic Field - ElectroMagnetic
Field - Near the Antenna - Losses - Near Field - Fresnel Zone - Farfield -
Summary - by W8JI
http://www.w8ji.com/radiation_and_fields.htm

Shielded Loop Antenna WebPage presented by Doug "K8RFT"
This personal webpage describes How To Make a Loop Antenna with Seven Feet of
Six-Conductor Shielded Cable formed into a Circle and with the conductors
connected in series to form a Six-Turn Loop Antenna. Original "Plans" from
BeRadio.Com
http://user.netonecom.net/~swordman/Radio/shloopant.htm

Shielded-Loop AM Antenna
BeRadio.Com presents the "AM Loop Shielded Antenna for AM Reception:The loop
self resonates approximately in the middle of the AM band, and by adding or
subtracting turns it can be optimized higher or lower in the band.
http://notebook.beradio.com/ar/radio_shieldedloop_am_antenna/index.htm

Shielded-Loop Receiving Antenna by N5FC
Shielded-Loop antennas have some nice properties that make them desirable as
portable receiving antennas.
http://www.io.com/~n5fc/loop_ant.html


Justice AM Antenna a Review by RadioCorner.Com
Developed by Chris Justice from the C. Crane Company, the Justice AM antenna is
the best solution for pulling in a weak or, in some cases a station you never
thought existed. The antenna uses a new patented technology called "Twin Coil
Ferrite" that uses a regular ferrite rod antenna in a very unusual fashion.
http://www.radiocorner.com/amradio/amantennas.html


Antique Electronic Supply
A sorts of older variable tuning capacitors for your loop antenna that needs one
bad.
http://www.tubesandmore.com

Fair Radio Sales
A wide variety of electronic components, radios, and variable capacitors for
your loop antenna
http://www.fairradio.com/airvar.htm

Ocean State Electronics
Rhode Island's best selection for a wide variety of the best tuning capacitors
for reasonable price, tell them that electronicdx (Adam Ebel) sent you.
http://www.oselectronics.com/ose_p96.htm

The Crystal Set Society
Here are some capacitor available from a club that devotes to Crystal Set Radio
http://www.midnightscience.com/catalog5.html

The Surplus Sales of Nebraska
This surplus store based in the state of Nebraska, has the one you might need,
but they have minumim order policy
http://www.surplussales.com/Variables/AirVariables/AirVar1.html


Dan Small Parts and Kits
Dan's wide selection from Canada.
http://www.danssmallpartsandkits.net/


American Science and Surplus
A big spool of wire here just about for AM
http://www.sciplus.com/category.cfm?subsection=15&category=150

DigiKey.com
For ribbon cable and other sorts of wire.
http://www.digikey.com

Femco Magnet Wire
Femco Magnet Wire is a joint venture company that has been supplying round
insulated copper magnet (winding) wire to the transplant market since 1988.
http://www.femcomagnetwire.com/

Litz-Wire,com
Welcome to Litz-Wire.com!
http://www.litz-wire.com/

MCM electronics
They do sell wire and magnet wire here
http://www.mcmelectronics.com

MWS Industries
A place for all sorts of wire for business and industry
http://www.mwswire.com

Magnet Wire from Radio Shack
This is what I use often
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5\
F011%5F010%5F004%5F000&product%5Fid=278%2D1345

Mouser Electronics
Mouser has the biggest spools here for a great price, that makes sense
http://www.mouser.com

Ocean State Electronics
magnet wire at a good price
http://www.oselectronics.com

WIRE "Flex-Weave" Antenna Wire
"Flex-Weave" is a hybrid aerial wire that consists of 168 strands of woven #36
solid copper wires that provide high strength and extreme flexibility. The most
popular version of "Flex-Weave" is the 'equivalent' of #14 AWG wire size. It can
be 'used' for unsupported spans up to 200 ft (100-150 ft in areas with high ice
and wind loading).
http://www.radio-ware.com/products/fw.htm

WIRE "QuietFlex" Antenna Wire by Antennas & More: Insulated, Strong, Flexible
and Durable
"QuietFlex" Antenna Wire by Antennas & More: "QuietFlex" #14 AWG Wire has more
than 41 Strands tightly twisted together under its Flexible Insulation making it
both Strong, Flexible and Durable.
http://www.antennasmore.com/wire&.htm


Scanning, Ham Radio and Public Safety Resources
- Links to the various webpages with resources for the Ham Radio Operator and
Scanning Enthusiast. Resources such as; Monitoring Police and Fire
Communications, What Antennas to use, Secret Scanner Frequencies, Radio
Programming Software, Radio Mods and Operating Tips, Professional resources for
Public Safety Management, Guidance and Self-Help.
http://myweb.accessus.net/~090/resources-ps.html

"SW-Radio Galaxy International"
Free Radio From The Netherlands
http://www.swrgalaxy.tk

11 meter band
rsn is a radio group on 11 meter for rad-oper world wide rsn truckers
http://rsn11meterbandtex2div.bravehost.com/


Stormwise - Supplier of large VLF ferrite rods.
http://www.stormwise.com/vlf.htm
Amidon Ferrite rods, bars, plates, and tubes.
http://www.amidoncorp.com/aai_ferriterods.htm

Bytemark Ferrite rods, bars, plates, and tubes.
http://www.bytemark.com/products/rod1.htm

hi from austria,

i would like to build a broadband loop (50khz - 30 mhz) for my perseus sdr.
i found a very interesting curcuit- and building plan here
http://wl1030.com/content/ and there was a group which has build several
broadband loops http://www.ng-ronde.nl/wl1030/ . those who are interested in
this loop can download the general info of this loop here, it´s the file
"WL1030":
http://www.4shared.com/account/dir/6459794/8254f480/sharing.html?rnd=0

does anyone of you already built such a loop or heard something about it´s
usefulness in practice? any comment is welcome!

thx
gerhard

Hallo Gerhard

my only comment is that the OP AMPs while very good do not offer the noise floor
obtainable with other circuits such as those of Chris Trask and the original
Norton ampifiers.  Lankford in a recent post shows his remaining interest in
push pull Norton amps.

However, as Chris has pointed out we need a solution wherein the amplifier's
characteristics need to be somewhat constant with the frequency varying value of
the loop impedance to be optimally useful.

so after some consideration a year back I decided to wait after I can looked
carefully at the Dutch site.

best

Paul in Guelph von KANADA


----- Original Message ----
From: Gerhard Baumgartner <gjmb@...>
To: loopantennas@yahoogroups.com
Sent: Monday, June 30, 2008 11:49:32 AM
Subject: [loopantennas] experience with this "new"  broadband loop ?


hi from austria,

i would like to build a broadband loop (50khz - 30 mhz) for my perseus sdr.
i found a very interesting curcuit- and building plan here
http://wl1030. com/content/ and there was a group which has build several
broadband loops http://www.ng- ronde.nl/ wl1030/ . those who are interested in
this loop can download the general info of this loop here, it´s the file
"WL1030":
http://www.4shared. com/account/ dir/6459794/ 8254f480/ sharing.html? rnd=0

does anyone of you already built such a loop or heard something about it´s
usefulness in practice? any comment is welcome!

thx
gerhard



[Non-text portions of this message have been removed]

>
> > i would like to build a broadband loop (50khz - 30 mhz) for my perseus
> > sdr.  i found a very interesting curcuit- and building plan here
> > http://wl1030.com/content/ and there was a group which has build several
> > broadband loops http://www.ng- ronde.nl/ wl1030/ . those who are
interested
> > in this loop can download the general info of this loop here, it´s the
file
> >
"WL1030":http://www.4shared.com/account/dir/6459794/8254f480/sharing.html?rn
d=0
> >
> > does anyone of you already built such a loop or heard something about
it´s
> > usefulness in practice? any comment is welcome!
> >
>
>
> my only comment is that the OP AMPs while very good do not offer the noise
> floor obtainable with other circuits such as those of Chris Trask and the
> original Norton ampifiers.  Lankford in a recent post shows his remaining
> interest in push pull Norton amps.
>
> However, as Chris has pointed out we need a solution wherein the
amplifier's
> characteristics need to be somewhat constant with the frequency varying
value
> of the loop impedance to be optimally useful.
>
> so after some consideration a year back I decided to wait after I can
looked
> carefully at the Dutch site.
>


     I've been looking at the loop impedance problem.  There is a paper by a
group of Russian HF radio astronomers who have a procedure for matching
short dipoles to 75-ohms over a wide bandwidth, and I'm going to see if
their synthesis procedure can be used to match a loop over a wide bandwidth.
Problem is that the loop is a low resistance in series with an inductance,
whereas the dipole is a large resistance in series with a small capacitor.
At first glance, it seems that the synthesis procedure for the loop is a
dual of the one for the dipole.  If that proves to be true, then it should
be relatively simple.

     The Russians followed the matching network with a two-stage balanced
lossless feedback amplifier.  That's a bit ambitious, but they are dealing
with extremely small signal levels and they need a good high dynamic range
amplfier to accomplish their goal.


Chris

      ,----------------------.       High Performance Mixers and
     /    What's all this     \    Amplifiers for RF Communications
    / extinct stuff, anyhow?  /
    \  _______,--------------'           Chris Trask / N7ZWY
   _ |/                                  Principal Engineer
  oo\                                  Sonoran Radio Research
(__)\       _                             P.O. Box 25240
   \  \    .'  `.                     Tempe, Arizona 85285-5240
    \  \  /      \
     \  '"        \                 IEEE Senior Member #40274515
      .       (  ) \
       '-| )__| :.  \              Email: christrask@...
         | |  | | \  '.       http://www.home.earthlink.net/~christrask
        c__; c__;  '-..'>.__

                        Graphics by Loek Frederiks

Problem is that the loop is a low resistance in series with an inductance,
whereas the dipole is a large resistance in series with a small capacitor.
At first glance, it seems that the synthesis procedure for the loop is a
dual of the one for the dipole.  If that proves to be true, then it should
be relatively simple.

*************************

My gut feel here Chris is likely you have it in the dual mathematics as you have
noted above.   Very good.

It can be a most important result to recognize "duals" in problems as sometimes
the dual is easier to implement.However here I guess we are changing 
capacitance for inductance but perhaps resistance for mhos (some JFET
configuration as it is a transconductance device).  So look at the paper and see
if this makes sense.  An inverse dual? is another notion here

best wishes and good thinking




Paul

[Non-text portions of this message have been removed]

chris and paul,

thx for your comments to this very interesting and delicate topic. now i
don´t wonder anymore why i didn´t find much in the internet about broadband
loops for selfbuilders.

info for the other members of this group. have a look in this group
"Shortwave-SWL-Antenna@yahoogroups.com", i posted there the question too and
chris chris answered, might be of interest to you.

paul you wrote:
>so after some consideration a year back I decided to wait after I can
looked carefully at the Dutch site.
don´t understand the meaning, would you please explain? hope i asked
politely, don´t know how to use the subtle nuances in the english language.

looking forward what comes next in this amp-topic. it would be great if
there is a selftuning broadband loop for selfbuilders.

best
gerhard

--- In loopantennas@yahoogroups.com, "gmcjetpilot" <gmcjetpilot@...>
wrote:
>
> That is a nice LOOP kit and it is for MW or for AM radio broadcast,
> not SW.


He's referring to this loop at MTM Scientific:

http://www.mtmscientific.com/swloop.html

No, actually that loop is for SW.  It is a 1 turn loop with a 9.5-365
pf variable cap.  If your run 1 turn loops of various reasonable
sizes through the calculators online, including Bruce Carter's, they
will fall in the SW range.

http://www.mindspring.com/~loop_antenna/umr_emc_calc.htm

Using that calculator, 1 turn, 36" sides, gives 3.8 mhz - 23.6 mhz.

With 1 turn, 30" sides, it gives 4.2 mhz - 27.2 mhz.

If 1 turn, 24" sides, it gives 4.8 mhz -29.8 mhz.

MTM scientific has a 15 turn tuned loop, 17" sides, that covers the
MW/AM band:

http://www.mtmscientific.com/loop.html

I have photos of my MTM AM loop in the Photos section in the Loop
Kits folder.

Paul C.
tenorman1952

paul you wrote:
>so after some consideration a year back I decided to wait after I can
looked carefully at the Dutch site.
don´t understand the meaning, would you please explain? hope i asked
politely, don´t know how to use the subtle nuances in the english language.


*******************


sorry the problem was my english


I meant to say I looked very closely at the design of the Dutch amp and decided
it was not good enough on noise as compared to existing other amps such as those
of Chris and Dallas.  It was the noise in the OP AMP that bother me.  The OP AMP
is a good solution except for the noise floor being to high.


hope that helps


Paul

[Non-text portions of this message have been removed]

paul wrote:
>It can be a most important result to recognize "duals"
>in problems as sometimes the dual is easier to implement.
>However here I guess we are changing capacitance for
>inductance but perhaps resistance for mhos
>(some JFET configuration as it is a transconductance device).
>So look at the paper and see if this makes sense.
>An inverse dual? is another notion here

>I meant to say I looked very closely at the design of the Dutch amp and
>decided it was not good enough on noise as compared to existing
>other amps such as those of Chris and Dallas.
>It was the noise in the OP AMP that bother me.
>The OP AMP is a good solution except for the noise floor being to high.
>best wishes and good thinking

paul,
your comments sound promising, but i can´t transform them to the reality
of a working circuit. i simply miss the knowledge do to that for myself.

can you tell me exactly (part and value) what has to be changed in the
published circuit of the wl1030 to make it work properly.

or can you tell me which amp circuit i should take instead. but i need a
circuit with exact values.

i will have a look at chris paper http://tinyurl.com/ytsf6k the next days to
see if i can handle
anything of it alone. i am used to do some math as i work also on noise
analysis of random
processes - found out that there are structures in the noise but they are
fractally
dispersed and correlated with cosmic attractors, cause of noise it not
(always) anisotropic - but this
has basically nothing to do with the knowledge of electronic circuits. so
will see what i
can bring out for myself of chris paper.

gerhard

----- Original Message ----
From: Gerhard Baumgartner <gjmb@...>
To: loopantennas@yahoogroups.com
Sent: Wednesday, July 2, 2008 2:43:13 PM
Subject: [loopantennas] circuit for the selftuning broadband loop


paul wrote:
>It can be a most important result to recognize "duals"
>in problems as sometimes the dual is easier to implement.
>However here I guess we are changing capacitance for
>inductance but perhaps resistance for mhos
>(some JFET configuration as it is a transconductance device).
>So look at the paper and see if this makes sense.
>An inverse dual? is another notion here

>I meant to say I looked very closely at the design of the Dutch amp and
>decided it was not good enough on noise as compared to existing
>other amps such as those of Chris and Dallas.
>It was the noise in the OP AMP that bother me.
>The OP AMP is a good solution except for the noise floor being to high.
>best wishes and good thinking

paul,
your comments sound promising, but i can´t transform them to the reality
of a working circuit. i simply miss the knowledge do to that for myself.

can you tell me exactly (part and value) what has to be changed in the
published circuit of the wl1030 to make it work properly.

It will work but just might be more noisy.  What I can suggest is to tackle the 
other end by purchasing a DSP audio filter like the West Mountain ClearSpeech
from hamcity.com.

This is what Chris is now trying to do to define a circuit that would work well
so I think I will defer to Chris here.but I do suggest anyways for listening to
have a good modern DSP and certainly the ClearSpeech is a good one


http://www.hamcity.com/detail.aspx?ID=1878
here is where you can buy it best price, with your High EURO it might be a good
deal.
I also use a Sounds Sweet speaker on my audio output as
well.http://www.soundssweet.com/




this does not address the noise problem per se in the rf amp but can help with
the audio noise reduction available via the DSP and the good less hiss speaker


best
Paul

[Non-text portions of this message have been removed]

Hi Chris,

Do you have a pointer to the Russian document?

Thanks, Jon W1MNK


>
>
> I've been looking at the loop impedance problem. There is a paper by a
> group of Russian HF radio astronomers who have a procedure for matching
> short dipoles to 75-ohms over a wide bandwidth, and I'm going to see if
> their synthesis procedure can be used to match a loop over a wide
> bandwidth.
> Problem is that the loop is a low resistance in series with an inductance,
> whereas the dipole is a large resistance in series with a small capacitor.
> At first glance, it seems that the synthesis procedure for the loop is a
> dual of the one for the dipole. If that proves to be true, then it should
> be relatively simple.
>
> The Russians followed the matching network with a two-stage balanced
> lossless feedback amplifier. That's a bit ambitious, but they are dealing
> with extremely small signal levels and they need a good high dynamic range
> amplfier to accomplish their goal.
>
> Chris
>
> ,----------------------. High Performance Mixers and
> / What's all this \ Amplifiers for RF Communications
> / extinct stuff, anyhow? /
> \ _______,--------------' Chris Trask / N7ZWY
> _ |/ Principal Engineer
> oo\ Sonoran Radio Research
> (__)\ _ P.O. Box 25240
> \ \ .' `. Tempe, Arizona 85285-5240
> \ \ / \
> \ '" \ IEEE Senior Member #40274515
> . ( ) \
> '-| )__| :. \ Email: christrask@...
> <mailto:christrask%40earthlink.net>
> | | | | \ '. http://www.home.earthlink.net/~christrask
> <http://www.home.earthlink.net/%7Echristrask>
> c__; c__; '-..'>.__
>
> Graphics by Loek Frederiks
>
> __._,_.__
> .
>
>


[Non-text portions of this message have been removed]

>
> Hi Chris,
>
> Do you have a pointer to the Russian document?
>
> Thanks, Jon W1MNK
>

     No, it's out of the journal "Experimental Astronomy" and you can't
access it online except with an account.  I access it at the university
engineering library.  I just tried uploading it into the group files
section, but it didn't accept it, probably because it's a little more than
3M in size.

Chris

      ,----------------------.       High Performance Mixers and
     /    What's all this     \    Amplifiers for RF Communications
    / extinct stuff, anyhow?  /
    \  _______,--------------'           Chris Trask / N7ZWY
   _ |/                                  Principal Engineer
  oo\                                  Sonoran Radio Research
(__)\       _                             P.O. Box 25240
   \  \    .'  `.                     Tempe, Arizona 85285-5240
    \  \  /      \
     \  '"        \                 IEEE Senior Member #40274515
      .       (  ) \
       '-| )__| :.  \              Email: christrask@...
         | |  | | \  '.       http://www.home.earthlink.net/~christrask
        c__; c__;  '-..'>.__

                        Graphics by Loek Frederiks

Hal S. said, "4. Twist the wire ends together approximately 2 turns per inch
(I made a change here. On the base, I installed a two-wire terminal so I
could easily connect a different length lead wire. I connected the ends of
the wire from the loop to the terminal block and then connected a shielded
wire to the terminal block to act as a lead-in. The ground (shield) lead
connects to the ground terminal of the radio, the center wire connects to
the "external AM antenna" terminal of the radio. You may have to experiment
with your own radio to find what works best)."

Hal,
1. Do I understand you twist the antenna loop ends together?
2. What is "approximately 2 turns per inch?"
3. What is the "two-wire terminal" and how do you fashion two wires if the
antenna ends are twisted together?
4. What kind of terminal block do you describe?
5. What kind of shielded wire do you use for the terminal block?
6. Once built, is there any kind of tuning, V-cap or does the radio receiver
need to be in close proximity?

William W."Bill" McGraw
"Somewhere South of Chicago"
Greenville, MS 38701

In a message dated 03/07/2008 08:57:48 GMT Daylight Time,
mcgr3799@... writes:

Hal S. said, "4. Twist the wire ends together approximately 2 turns per
inch.........

Hal,
1. Do I understand you twist the antenna loop ends  together?
2. What is "approximately 2 turns per inch?"

---------------------------

Hi Bill

I'm not sure what the original reference was, so don't have any details of
this particular loop and can't comment on any of the other questions, but this
won't mean twist together in the sense of a tight twist just to join right at
  the very end.

The implication seems to me that you should expect to have some  wire "ends",
let's say each two feet long just for example, presumably after  constructing
the loop, and it's these you're supposed to twist together along  their
length so you end up with a twisted pair of wires.
Approximately two turns per inch will mean just that, as you twist it
together allow approx two turns every inch of wire, ie don't twist it too 
tight.

Not knowing the original source, I can't say exactly what you're supposed  to
with it after that nor if these "ends" are from a main loop or coupling loop,
  but would guess that could be the connection to your radio:-)

regards

Nigel
GM8PZR

ANY HELP OR ADVICE.

I want to make a passive loop with a high and low
range by tapping into the inductive winding in the
middle and using a using a two-in-one ganged capacitor
(some how).

Size: 2' x 2' square loop on a X wood frame.
Edge wound: 18 turns (144')
Width: 3.5" (approx)
Capacitor: 12 - 390 pf x 2 (ganged together)
Connection: Inductive and/or direct feed w/ sense loop'(s)

The AM loop calculator says the low end is about 400- 2250Khz.

Tap 1/2 way (9 turns) the high end is 800 - 4500 Khz (in theory).

I will have a  secondary "sense" winding (single loop).
Not sure if one or two separate senese loops are needed for
each the high and the low ranges?

I'm not sure if I should put that SENSE wire in line
with the inductive winding, or inside the the windings.

I could put the sense loop in middle of inductive windings side,
with 8 windings on each side. However when I tap 1/2 the windings
the sense wire will be on the edge.

A better idea might be put the sense wire inside the
2' x 2' frame, for example a 1.5 foot diameter (round or
square) sense wire. That could handle both bands.

To switch between the HI and LO freq I could just
use two feed lines or have a terminal block and
connect the coaxial feed to different terminals as
needed.

I'm not sure if I need a switch to open the circuit to
the two ranges.

Any help or advice would be nice for my idea of
having a two in one loop.

Thanks George

gmcjetpilot wrote:
> ANY HELP OR ADVICE.
>
> I want to make a passive loop with a high and low
> range by tapping into the inductive winding in the
> middle and using a using a two-in-one ganged capacitor
> (some how).
>
> Size: 2' x 2' square loop on a X wood frame.
> Edge wound: 18 turns (144')
> Width: 3.5" (approx)
> Capacitor: 12 - 390 pf x 2 (ganged together)
> Connection: Inductive and/or direct feed w/ sense loop'(s)
>
> The AM loop calculator says the low end is about 400- 2250Khz.
>
> Tap 1/2 way (9 turns) the high end is 800 - 4500 Khz (in theory).
>
> I will have a  secondary "sense" winding (single loop).
> Not sure if one or two separate senese loops are needed for
> each the high and the low ranges?
>
> I'm not sure if I should put that SENSE wire in line
> with the inductive winding, or inside the the windings.
>
> I could put the sense loop in middle of inductive windings side,
> with 8 windings on each side. However when I tap 1/2 the windings
> the sense wire will be on the edge.
>
> A better idea might be put the sense wire inside the
> 2' x 2' frame, for example a 1.5 foot diameter (round or
> square) sense wire. That could handle both bands.
>
> To switch between the HI and LO freq I could just
> use two feed lines or have a terminal block and
> connect the coaxial feed to different terminals as
> needed.
>
> I'm not sure if I need a switch to open the circuit to
> the two ranges.
>
> Any help or advice would be nice for my idea of
> having a two in one loop.

To range switch, have you considered breaking the loop into
two 9 turn sections and use a DPDT switch or relay to
connect them in series or parallel?  With one tuning
capacitor this should jump the frequency range about 2:1.  I
think this gives you a higher Q and better tuning range than
just letting 9 turns hang on the end of the 9 you are using.

--
Regards,

John Popelish

At 01:46 AM 7/7/2008 +0000, you wrote:

>ANY HELP OR ADVICE.
>
>I want to make a passive loop with a high and low
>range by tapping into the inductive winding in the
>middle and using a using a two-in-one ganged capacitor
>(some how).
>
>Size: 2' x 2' square loop on a X wood frame.
>Edge wound: 18 turns (144')
>Width: 3.5" (approx)
>Capacitor: 12 - 390 pf x 2 (ganged together)
>Connection: Inductive and/or direct feed w/ sense loop'(s)
>
>The AM loop calculator says the low end is about 400- 2250Khz.
>
>Tap 1/2 way (9 turns) the high end is 800 - 4500 Khz (in theory).
>
>I will have a secondary "sense" winding (single loop).
>Not sure if one or two separate senese loops are needed for
>each the high and the low ranges?
>
>I'm not sure if I should put that SENSE wire in line
>with the inductive winding, or inside the the windings.
>
>I could put the sense loop in middle of inductive windings side,
>with 8 windings on each side. However when I tap 1/2 the windings
>the sense wire will be on the edge.
>
>A better idea might be put the sense wire inside the
>2' x 2' frame, for example a 1.5 foot diameter (round or
>square) sense wire. That could handle both bands.
>
>To switch between the HI and LO freq I could just
>use two feed lines or have a terminal block and
>connect the coaxial feed to different terminals as
>needed.
>
>I'm not sure if I need a switch to open the circuit to
>the two ranges.
>
>Any help or advice would be nice for my idea of
>having a two in one loop.
>
>Thanks George

Hi George,

Yes, it is possible to use a 2 gang capacitor to simultaneously tune 2
separate inductors.  One inductor ... usually the one tuning the higher
frequencies will be tuned by the 2 capacitors in a series
configuration.  The second inductor is connected across one of the
gangs.  If you are using a standard 2 gang capacitor which is 350 pfd each
.... then the first inductor (usually the smaller one for higher
frequencies) is connected across the 2 gangs in series ... eg maximum value
of 365 pfd / 2 = 182.5  while the second inductor would be connected across
one of the 2 gangs eg 365 pfd.

The output would be via a link winding or link windings.  It is certainly
not a common method .... at least not in recent times.  However, in the
past this was a common method of constructing a mult-band output load for
RF transmitters .... which reduces or avoids switching.  You would have to
look for this circuit in Radio Handbooks of a late 40's or early 50's
vintage to see examples.   It is also a similar concept for a version of
antenna tuner (known as the Z-match) which is also a relatively old
configuration (back when parallel open wire feed lines were standard).  Now
that multiband antennas fed with open wire line are starting to become
popular again the Z-match is experiencing a resurgence.  I have never seen
the concept applied to small receiving loops.

I think it would be an interesting project.

Jim

--- In loopantennas@yahoogroups.com, "gmcjetpilot" <gmcjetpilot@...>
wrote:
>
> ANY HELP OR ADVICE.
>
> I want to make a passive loop with a high and low
> range by tapping into the inductive winding in the
> middle and using a using a two-in-one ganged capacitor
> (some how).
>
> Size: 2' x 2' square loop on a X wood frame.
> Edge wound: 18 turns (144')
> Width: 3.5" (approx)
> Capacitor: 12 - 390 pf x 2 (ganged together)
> Connection: Inductive and/or direct feed w/ sense loop'(s)
>
> The AM loop calculator says the low end is about 400- 2250Khz.
>
> Tap 1/2 way (9 turns) the high end is 800 - 4500 Khz (in theory).

Why tap in the middle, 9 tunrs.  You would have a lot of wasted
overlap of the two ranges.

If instead you tapped off just 3 turns, you would have a range of
about 2000 khz - 11,000 khz.  I am probablly using the same
calculator you are,

http://www.mindspring.com/~loop_antenna/amloop_calc4.htm

and using 24" x 24", .75" wide, 3 turns, 12-390 pf.

So your low range would be 18 turns, and cover 400 - 2250 khz, and
high range would be 3 turns, and cover 2000 - 11,000 khz.

Paul C.
tenorman1952

At 11:19 AM 7/7/2008 -0400, you wrote:

>At 01:46 AM 7/7/2008 +0000, you wrote:
>
> >ANY HELP OR ADVICE.
> >
> >I want to make a passive loop with a high and low
> >range by tapping into the inductive winding in the
> >middle and using a using a two-in-one ganged capacitor
> >(some how).
> >
> >Size: 2' x 2' square loop on a X wood frame.
> >Edge wound: 18 turns (144')
> >Width: 3.5" (approx)
> >Capacitor: 12 - 390 pf x 2 (ganged together)
> >Connection: Inductive and/or direct feed w/ sense loop'(s)
> >
> >The AM loop calculator says the low end is about 400- 2250Khz.
> >
> >Tap 1/2 way (9 turns) the high end is 800 - 4500 Khz (in theory).
> >
>
>
>Yes, it is possible to use a 2 gang capacitor to simultaneously tune 2
>separate inductors. One inductor ... usually the one tuning the higher
>frequencies will be tuned by the 2 capacitors in a series
>configuration. The second inductor is connected across one of the
>gangs. If you are using a standard 2 gang capacitor which is 350 pfd each
>.... then the first inductor (usually the smaller one for higher
>frequencies) is connected across the 2 gangs in series ... eg maximum value
>of 365 pfd / 2 = 182.5 while the second inductor would be connected across
>one of the 2 gangs eg 365 pfd.
>
>The output would be via a link winding or link windings. It is certainly
>not a common method .... at least not in recent times. However, in the
>past this was a common method of constructing a mult-band output load for
>RF transmitters .... which reduces or avoids switching. You would have to
>look for this circuit in Radio Handbooks of a late 40's or early 50's
>vintage to see examples. It is also a similar concept for a version of
>antenna tuner (known as the Z-match) which is also a relatively old
>configuration (back when parallel open wire feed lines were standard). Now
>that multiband antennas fed with open wire line are starting to become
>popular again the Z-match is experiencing a resurgence. I have never seen
>the concept applied to small receiving loops.
>
>I think it would be an interesting project.
>
>Jim


   This is an addendum to my last posting .... I suggest a possible strategy
would to consider the Z-match antenna tuner circuit.  In that circuit 2
separate inductors are tuned by a single 2 gang capacitor as outlined above
... However, since you are using the inductors as antennas themselves
(loops) you do not need the input link windings.  In the Z-match circuit
the inductors/loops are coupled to the receiver via a series capacitor
which in effect produces a L match circuit.  You would need a second single
gang capacitor.  You would then have no switching at all.

You could wind a standard loop for MW and second loop for SW ..... fit one
inside the other and put them at right angles to each other to avoid
interaction.  Heh it sounds so good I may try it myself hi hi.

One capacitor (the 2 gang) would tune the loops, and the second capacitor
would match the input to the receiver.  You can find the Z-match circuit
on-line.  The number of turns on each loop would be experimental to some
degree. It would also be possible to use a single loop with an appropriate
tap ... however adjusting the relative inductances would take much more
careful experimentation.

Jim

I have a 10 meter full wave loop. Apex at 25 foot each lower leg of
loop is 10 foot off the ground. It works real good what you hear you
can work. The only thing wrong is the rf in the shack it gets into my
rotor control box and a small tv monitor next to the radio transmitter.
This is the w5sdc Delta loop for hf with a 4to1 balum and fed with RG-8
coax it is also wound with 8 turns of the feed line under the antenna.
No tunner needed on all of the 10 meter band. My radio yeasu 847 is
grounded and the antenna tunner is also grounded but still some rf in
shack. Any Idea on what to do to keep the rf outside?
Thanks
Dan
N6TKW

At 07:02 PM 7/7/2008 +0000, you wrote:

>I have a 10 meter full wave loop. Apex at 25 foot each lower leg of
>loop is 10 foot off the ground. It works real good what you hear you
>can work. The only thing wrong is the rf in the shack it gets into my
>rotor control box and a small tv monitor next to the radio transmitter.
>This is the w5sdc Delta loop for hf with a 4to1 balum and fed with RG-8
>coax it is also wound with 8 turns of the feed line under the antenna.
>No tunner needed on all of the 10 meter band. My radio yeasu 847 is
>grounded and the antenna tunner is also grounded but still some rf in
>shack. Any Idea on what to do to keep the rf outside?
>Thanks
>Dan
>N6TKW


Hi Dan,

I believe W5SDC feeds his loop at the apex .... I assume you are doing so
as well.  I suggest you try feeding it at one of the lower corners and move
the feed line out of the loop aperture.  Since the bottom is only 10 ft off
the ground you should have little difficulty with the experiment.

Jim, VE3CI

To Jim & Paul.............

>Posted by: "Jim Dunstan" dunstan@... norlink88
>
>Mon Jul 7, 2008 8:21 am (PDT)
>
>Yes, it is possible to use a 2 gang capacitor to simultaneously tune
>2 separate inductors. One inductor ... >usually the one tuning the
>higher frequencies will be tuned >by the 2 capacitors in a series
>configuration. The second >inductor is connected across one of the
>gangs. If you are >using a standard 2 gang capacitor which is 350
>pfd each

Good idea I did not think of ganging the two together.

>It is also a similar concept for a version of antenna tuner (known
>as the Z-match) which is also a relatively old configuration (back
>when parallel open wire feed lines were standard). Now that
>multiband antennas fed with open wire line are starting to become
>popular again the Z-match is experiencing a resurgence. I have
>never seen the concept applied to small receiving loops.

You lost me a little but I'll do research. I really want to keep it
simple. I would love to have a two band loop. The going in position
is keep it simple, min parts, switches and so on.

I guess one way would be just make two loops on one frame with two
feed lines or may be a toggle switch to switch from a single to
ganged capacitor and loop A or B, but thanks for the great advice.



>Posted by: "tenorman1952" tenorman1952@...   tenorman1952
>
>Mon Jul 7, 2008 8:34 am (PDT)
>
>Why tap in the middle, 9 tunrs. You would have a lot of wasted
>overlap of the two ranges.

Thanks Paul makes sense. So if its just 3 turns, I'll just have a
full 3 turns + 18 turns, I have 900 feet of wire to play with. Great
thanks.



>Posted by: "Jim Dunstan" dunstan@...   norlink88
>
>Mon Jul 7, 2008 9:01 am (PDT)
>consider the Z-match antenna tuner circuit. In that circuit 2
>separate inductors are tuned by a single 2 gang capacitor as
>outlined above ... However, since you are using the inductors as
>antennas themselves (loops) you do not need the input link
>windings. In the Z-match circuit the inductors/loops are coupled to
>the receiver via a series capacitor which in effect produces a L
>match circuit. You would need a second single gang capacitor. You
>would then have no switching at all.

Thanks Jim that sounds interesting. Since this is my first real LOOP
(I'm going to try and may nice looking and sounding) I may set my
sights lower for a simple loop. However I'll save you post for my
next loop.

I leaning to just having too loops (really quite separate) on the
same frame, may be only sharing the same capacitor and sense loop
wire. I may use manual switching or a terminal to swap, changing from
Low to High range.

Cheers George

Chris e-mail the file to me, and I'll convert it to PDFs and then
split them so that they will load up on the site.

Best Regards
Bob

--- In loopantennas@yahoogroups.com, "Chris Trask" <christrask@...> wrote:
>
> >
> > Hi Chris,
> >
> > Do you have a pointer to the Russian document?
> >
> > Thanks, Jon W1MNK
> >
>
>     No, it's out of the journal "Experimental Astronomy" and you can't
> access it online except with an account.  I access it at the university
> engineering library.  I just tried uploading it into the group files
> section, but it didn't accept it, probably because it's a little
more than
> 3M in size.
>
> Chris
>
>      ,----------------------.       High Performance Mixers and
>     /    What's all this     \    Amplifiers for RF Communications
>    / extinct stuff, anyhow?  /
>    \  _______,--------------'           Chris Trask / N7ZWY
>   _ |/                                  Principal Engineer
>  oo\                                  Sonoran Radio Research
> (__)\       _                             P.O. Box 25240
>   \  \    .'  `.                     Tempe, Arizona 85285-5240
>    \  \  /      \
>     \  '"        \                 IEEE Senior Member #40274515
>      .       (  ) \
>       '-| )__| :.  \              Email: christrask@...
>         | |  | | \  '.       http://www.home.earthlink.net/~christrask
>        c__; c__;  '-..'>.__
>
>                        Graphics by Loek Frederiks
>

ANY INPUT COMMENTS OR SUGGESTIONS WOULD BE APPRECIATED
(please to not cut and past this whole long post in reply)

How should I test these three loops?

The tale of three Chinese loops
http://img525.imageshack.us/img525/7522/slide3copymh0.jpg

Terk and Tucsun MW/AM passive loops
http://img522.imageshack.us/img522/4841/slide2hh6.jpg

Kaito TG34 Active MW/SW loop
http://img522.imageshack.us/img522/1176/slide1fx3.jpg

I have more experience with the (DEGEN) TG34 loop, which I have owned
for many months. I have to say I am pleased with it and it always
impresses me, especially since it was only a $20 option bundled with
a DEGEN DE1103 radio I bought on eBay.

The two passive MW loops are the Terk AM Advantage and TECSUN AN-200.
I paid about the same $30 to $34 for them. The Terk is widely
avaiable in the US and the Tecsun is china and found on eBay (from
seller: liypn)

The TG34 can fit in a small bag when collapse and folded up, and it
has both MW and SW capability. It is not free standing and needs to
be hung from something, preferably in a window. The TG34 is an active
loop powered with two AAA batteries. My initial opinion or gut says
the TG34 is probably better than the two passive loops overall? I
still have to do some A, B & C comparisons.

All loops have the ability to connect direct or by "proximity" to the
radio. The active TG34 loop has the ability to directly connect to
the radio or passively with a repeater loop-stick.

The passive MW loops may do better than the TG34 when directly
connected to an AM radio with antenna terminals (I think). For
passive boost the TG34 may be better with it's cool little loopstick
repeater you can put right on-top of the radio, for best position
near the internal loop stick. On the other hand you have wires and
have to tape or hold that loop-stick repeater onto the radio. The
passive MW/AM loops sit next to the radio on one of 4 sides. I tried
putting them on top of a Sony (where I know the internal loopstick
was located). It did not work well with the loop sitting on the
radio, at least with this radio. It was better off to the front or
back with the edge of the loop ending where the loop stick started.
If I tried to "frame" the internal loop stick in the middle it did
not work well either.

QUALITY

The two passive loops are well made but the Terk seems a little more
stout (heavier) and has a nice rubberized base. The tuning knob on
the Terk is thumb type in the middle with a nice pointer and freq
scale (530-1600 but range goes past the scale).  The rubberized thumb
tuning dial is nice but a little harder to get at than the Tecsun.

The TECSUN AN-200 is pretty to look at (beauty in the eye of
beholder). They both have the same dia or very close, about 9" dia.
Counting the Tecsun it has 28 turns which is about 66 feet of
magnetic wire, 18 gauge? The winding is tight and may have some
adhesive holding them in position? The Terk winding is hidden and
assembled with recessed screws. The Tecsun has no visible fasteners
and looks snapped or glued together.

The Terk base is wider but not much more stable because of the higher
weight of the loop housing and the base is not symmetric, in stops
short on the back side and is flat, not extending past the loop as
far as the base extends on the front. Minor point but it makes it
want to tip backwards more. The Tecsun is more symmetric and being
lighter helps, but has about the same overall stability. Neither are
going to fall over on their own.

Both have 1/8" jacks to connect a cable for direct connect to the
radio. The Terk AM Advantage's cable is long and terminates to bare
wire. The Tecsun supplies a short cable with 1/8" phone plugs at both
ends, which may or may not work with many radios AM/MW antenna
connection jacks. No big deal there are workarounds for that.


TEST SO FAR

My first test was trying the passive loops on my home mini stereo
that has an AM radio and no internal antenna but does have two
terminals to attach an AM antenna. The results where as  expected,
very good with both. I really can't say one shine above the other,
may be the Terk had an edge but the Tecsun AN-200 was easier to tune.
For one the knob on the side was easier to get at and tune than the
thumb knob. However the Terk does have a Freq scale that is pretty
good. When I saw the scale I thought it might be a joke and planned
on ignoring it. However its not bad for getting close. Most will just
spin the knob for best signal but I can see where the scale can
improve that shotgun technique add some quasi precision guessing at
where to set it.

One thing I notice is the Terk seems to have a sharper null node and
sweet spot. The Tecsun was not as sharp and had broader sweet spot or
less sensitive. Terk with its thumb knob and freq scale was
surpisingly close as I said. The Tecsun has a generic  0 - 10 scale.
Both had about 180 degrees of rotation. The Tecsun tuning knob was
easier to get at and easier turn, but may be more susceptible to
accidentally being changed. The Terk knob had more resistance or
friction. The Tecsun was easy to spin. The Terk feel was not bad or
hard to use, just not as easy.

I tried both loops in passive mode as well. I used a Sony AM/FM
portable/table AC/DC radio. The results where also as expected, good,
but nothing definitive yet.

I'm always impressed with LOOPS, its like PFM, Pure Freaking Magic. I
could pull in a whole new station (on a different freq) by just
tuning the antennas. That is amazing (can some one explain that to
me)? I have had the experience where the directional nature of a loop
has rejected a weak station and brought in a new station, but they
both where on the same freq.

I have not had a chance to really try them out and will report back.
Please let me know what you think.

Questions?

Can any one tell my why the Tecsun tuning is more mellow and seems
less sensitive or wider sweet spot? It is affective but different
than the Terk which is like the TG34, very sharp null and sweet.

Not enough experience to tell yet which one is better, but like I
said for the money, wider band, portability, with the experience I do
have so far. The TG34 sold under different names like Kaito, Degen or
Generic as I have is a deal and better for a radio hobbyist. However
the TG34 has many parts and has to be hung-up, and its not pretty to
look at. It looks like a hanger. Behind blinds in a window its not
bad.

The MW/AM Loops are very simple and free standing. When boosting a
radio by proximity there are no wires or batteries. For just AM
radio, home use, the passive loops are better in the MW band. The
Tecsun is pretty to look at (to me). The Terk is not bad looking
either; it sits lower on its base. Also the Turk's med gray tends to
blend with typically gray or black radios well. The Tecsun red
magnetic wire yells LOOK.

Overall all these antennas are bargains and do what you expect and
probably a more, especially for the money.

I don't think these store bought passive MW/AM loops are going to be
as good as a LARGE well made home-brew loop. However its hard to fit
a 2-foot-by-2-foot loop on the coffee table or next to the radio on
the night-stand. I recommend all three antennas, and if I get any
more info I'll pass it along.

ANY INPUT COMMENTS OR SUGGESTIONS WOULD BE APPRECIATED

Cheers George

> Can any one tell my why the Tecsun tuning is more mellow and seems
> less sensitive or wider sweet spot? It is affective but different
> than the Terk which is like the TG34, very sharp null and sweet.
>

An educated guess says the Tecsun is not as sharp because they used
(from looks of picture) many many turns of small gauge wire. They
probably chose this approach for aesthetic appeal (sure looks good
doesn't it) because it actually works against the performance of the
antenna.

--- In loopantennas@yahoogroups.com, "gmcjetpilot" <gmcjetpilot@...>
wrote:
>
> ANY INPUT COMMENTS OR SUGGESTIONS WOULD BE APPRECIATED
> (please to not cut and past this whole long post in reply)
>

Thanks, George... very nice reviews!

Paul C.

CORRECTION I mislabled the pics

How should I test these three loops?

The tale of three Chinese loops
http://img525.imageshack.us/img525/7522/slide3copymh0.jpg

Terk and Tecsun MW/AM passive loops
http://img522.imageshack.us/img522/1176/slide1fx3.jpg

Kaito TG34 Active MW/SW loop
http://img522.imageshack.us/img522/4841/slide2hh6.jpg

--- In loopantennas@yahoogroups.com, "airchecklover" <mdh@...> wrote:
>
>
> > Can any one tell my why the Tecsun tuning is more mellow and
seems
> > less sensitive or wider sweet spot? It is affective but different
> > than the Terk which is like the TG34, very sharp null and sweet.
> >
>
> An educated guess says the Tecsun is not as sharp because they used
> (from looks of picture) many many turns of small gauge wire. They
> probably chose this approach for aesthetic appeal (sure looks good
> doesn't it) because it actually works against the performance of the
> antenna.
>

** TOO MANY TURNS **

???????? "many many turns of small gauge wire" ????????

It has 28 turns, which is about right according to the Loop Antenna
Calculator.

I just noticed on the inside of the loop there are three turns in the
middle, under the induction winding; this  must be the sense wire for
the direct connection.

You say too many turns of small gage wire? Does wire gage have
anything to do with it? If limited to 9" dia loop than how many turns
do you need?  With the loop calculator a 10-365 pf cap 28 turns gives
550 Khz -3380 Khz around a 7" x 7" frame (the calculator is for
square loops, so 7"x7" is equiv to 9" round in circumference or wire
length per turn).

I wounder what the TERK has inside. There are screws to disassemble
but something tells me not to to take this one apart.



** TUNING SENSITIVITY **

I have to say the Tecsun AN-200 has about the same gain as the Terk
in performance, from what I can tell. I am hard pressed to say there
is a big difference between the two passive loops. It is just that
the Tecsun has a less sharp edge tuning characteristic. I don't want
to say less sensitive, just not AS SENSITIVE to tuning the CAP.

Speaking of tuning sensitivity, the TG34 active loop is SUPER
SENSITIVE and with a tiny thumbnail tuning dial, it takes a precise
touch to get it dialed in.




** TEST CONTINUES **

Since I last wrote, I tried all three loops with my Degen DE1103. The
Degen must be maxed out already with the existing internal loop
stick, because none of the loops produce a significant gain. The
DE1103 does have an antenna jack input but not for MW, only for SW.
I'll try the MW loops on 160 meter.

I also revisited the Sony AM/FM portable/table radio. All loops
produce obvious and some times dramatic difference.  I got the TG34
out for side-by-side comparison to the passive loops.


** UPDATED CONCLUSION SO FAR **

As I thought and remembered, the TG34 does a little better with its
amplification and loop-stick repeater for "proximity" signal boosting
on the Sony table AM radio. The down side are the exta wires and
trying to position the soft loop in the window, which can be a pain.
Some stations are better with the loop perpendicular to the window (N-
S), other stations are better with loop flush to the window (E-W)
direction. I have to jury rig a support out from the top of the
window to hang the loop from, than tether to keep it from turning.

Tuning sensitivity of the TG34 with a small thumbnail dial on the
small amplifier module (the size of a large pack of gum) makes tuning
more touchy and harder than the others, at least with out practice.
Its easy to overshoot (again). Very small movement of tuning dial
makes a big difference. Of course the TG34 can do SW and is pretty
good up to about 9-13Mhz.

The passive loops are just right for the portable or table top AM
radio on a table. They are both nice, the Terk AM advantage and
Tecsun AN-200 are worth a look. I'm probably going to keep both, and
if have to decide on one, the choice would be hard. I would lean more
towards the Terk only because it comes with a better cord to connect
to radio and may be (?) a tad bit more gain (may be). However style
wise, the Tecsun AN-200 is pretty flashy. If the wife is involved
this would be a good one for her to decide based on style aesthetics
alone, since they perform pretty close.

MORE test to come? I'll keep you posted if I find anything else.

Cheers George