Hi All..... I have a question that I hope someone can help me with. I am planning to build an outdoor remote tuned loop antenna. I have read that you can find tuning diodes in the range of 40 - 700 pF. Does anyone have any experience with such diodes, and if so, where may I find them. Where I live, there are no electronic parts stores, so I will have to order them. Thanks in advance.


Nick Rumple
Kannapolis, North Carolina

Active AM Antenna With Twin Coil Ferrite by C. Crane Co.


JLKolb?s antenna links including the KRS AA-1 Active Antenna schematic, antenna preamplfiers, center-tapped loops, and a dual gate FET preselector.


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.


Kiwa - High Performance MW Air-Core Loop Antenna
High Performance MW Air-Core Loop Antenna by KIWA


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.


The Quantum loop antennas, now V2.0


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


WL1030 by the late Maartenhagg. Plans placed on this website by his friends in his honor.


C Crane Company
They sell the Justice AM Loop Antenna, Select A Tenna, Terk AM 1000


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


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


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



ALA-1530
Find the best UK LF/MF antenna here.


AOR
This is the site that sells the AOR loop


Kiwa Electronics
The maker of the air core loop antenna and other useful items that you may want on your wish list.


LF Engineering Company
A group of engineers, who make products for VLF/LF listening even ELF loops!


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
discontinued

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.


Torus Tuner Loop Company
A very specially made loop that is almost as big as a hula hoop
discontinued


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:
Use the Google Translate a web Page Tool to convert these webpages to English.



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.

* Twin Coil Ferrite AM Loop Antenna (Active)
- - -

* Torus Tuner 27" Loop Antenna (Passive)
- - - discontinued

* Select-A-Tenna Model #541M (Passive)
- - - discontinued

* Terk AM Advantage Loop Antenna (Passive)
- - -

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

* MTM Scientific AM Radio Loop Antenna (Passive)
*
- - - 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)

- - - discontinued

#2. * Torus Tuner 27" Loop Antenna (Passive)

- - - website gone

#3. * Select-A-Tenna Model #541M (Passive)

- - - website gone

#4. * Terk AM Advantage Loop Antenna (Passive)

- - -

#5. * RadioShack AM Loop Antanna # 15-1853 (Passive)

- - - Discontinued (Find 'used' on eBay)

* MTM Scientific AM Radio Loop Antenna (Passive)
*
- - - 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.


K9AY: How to Build the K9AY Loop Receiving Antenna
AY Technologies Antennas by K9AY. Excellent Antenna for Medium Wave Frequency DXing.


Six Foot Square by Six Turn Loop Antenna
New Mid-Size Loop Antenna by Graham Maynard with Matching Balanced Amplifier: Frequency Range 50KHz - 5000KHz.


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.



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


4 Foot Box loop antenna
Heres a 4 foot loop project by Bruce


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


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.


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.


Embrodary Loops
While these loop are for crafts, they can be a craft of art for improved AM radio reception!


Hard Core DXing
Here's what nordic dx has to offer in their discription of loops in this website


K5DKZ - Three Foot Box Loop Antenna Kit
Complete Parts and Plans for a 3 Ft Box Loop Antenna "Kit" ~$85+SH


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.


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.


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.



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.


"AM Loop Antenna Calculator" - by Bruce Carter
Here is a Great Tool for those Loop Antenna => "What Ifs...."


"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


* 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


Loop Antennas at Hard Core DX
TABLE: Number of Turns -v- Size of Loop in the Middle of this webpage.


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.


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


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


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



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.


Introduction to Broadcast Band AM/BCB/MW DXing
The International Radio Club of America (IRCA) WebPages



** 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.



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.



"3805er" 80-Meter balanced coax loop
Small shielded rx only loop for 80 meters


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


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


Shielded-Loop Receiving Antenna by N5FC
Shielded-Loop antennas have some nice properties that make them desirable as portable receiving antennas.


Antique Electronic Supply
A sorts of older variable tuning capacitors for your loop antenna that needs one bad.


Fair Radio Sales
A wide variety of electronic components, radios, and variable capacitors for your loop antenna


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.


The Crystal Set Society
Here are some capacitor available from a club that devotes to Crystal Set Radio


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



Dan Small Parts and Kits
Dan's wide selection from Canada.



American Science and Surplus
A big spool of wire here just about for AM


DigiKey.com
For ribbon cable and other sorts of wire.


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.


Litz-Wire,com
Welcome to Litz-Wire.com!


MCM electronics
They do sell wire and magnet wire here


MWS Industries
A place for all sorts of wire for business and industry


Magnet Wire from Radio Shack
This is what I use often


Mouser Electronics
Mouser has the biggest spools here for a great price, that makes sense


Ocean State Electronics
magnet wire at a good price


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).


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.


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.


Amidon Ferrite rods, bars, plates, and tubes.


Bytemark Ferrite rods, bars, plates, and tubes.

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: Please crop in to the important parts. For photos, JPG saves smaller and looks better, for line drawings GIF is smaller and looks better. Please do not use TIFF/TIF or BMP files, the file size is way too big and I may delete without notice.

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:

Or for more complex stuff, another free program is GIMP:

Attachments are now allowed, but please use judiciously. Rather than going out with the messages, they will be stored on the list but you'll get a link with the message.

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@...

Thanks,
Steve Greenfield

You might want to email him directly.

That is a very good question, BTW.

Steve Greenfield AE7HD

But my feedline I use is a run of Cat 5 ethernet cable, with one pair carrying the signal and the
other 3 pairs sharing the +V and 0V load. So I need to reconfigure the amplifier's T6 output
transformer for separate power feed, and balanced 100 ohm coming out.

It's actually fairly simple, and can be accomplished with a few modifications. First, break the connection
between T6 and C20, then connect your power line to C6, Q6, etc. to complete the supply connection. Done.

Looking at the output side of T6, break all of the shown connections. The upper terminal of the upper
winding is your + output, and the lower end of the lower winding is your - output. Connect the lower end of
the upper winging and the upper end of the lower winding to ground. Done.

The collectors of Q3 and Q4 will now see load impedances of 200 ohms instead of the original 400 ohms, so
the power gain will be reduced by 6dB.

Thanks Chris!

Hopefully the 6dB reduction won't be too much of a penalty. I would have to go to a different design for T6 to get the gain back?

Not easily and it wouldn't be worth the effort, but you could add an additional 3:2 autotransformer after it that would raise the collector load impedances to 450 ohms, which is reasonably close and would actually raise the gain by about 1.0dB. I don't have a drawing set for that readily available as I've never had to describe one, but it's fairly simple.



Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE

On 30/01/2014, at 2:18 AM, Chris Trask wrote:

But my feedline I use is a run of Cat 5 ethernet cable, with one pair carrying the signal and the
other 3 pairs sharing the +V and 0V load. So I need to reconfigure the amplifier's T6 output
transformer for separate power feed, and balanced 100 ohm coming out.

It's actually fairly simple, and can be accomplished with a few modifications. First, break the connection between T6 and C20, then connect your power line to C6, Q6, etc. to complete the supply connection. Done.

Looking at the output side of T6, break all of the shown connections. The upper terminal of the upper winding is your + output, and the lower end of the lower winding is your - output. Connect the lower end of the upper winging and the upper end of the lower winding to ground. Done.

The collectors of Q3 and Q4 will now see load impedances of 200 ohms instead of the original 400 ohms, so the power gain will be reduced by 6dB.

Thanks Chris!

Hopefully the 6dB reduction won't be too much of a penalty. I would have to go to a different design for T6 to get the gain back?

Cheers,

Andy
ZL3AG

But my feedline I use is a run of Cat 5 ethernet cable, with one pair carrying the signal and the
other 3 pairs sharing the +V and 0V load. So I need to reconfigure the amplifier's T6 output
transformer for separate power feed, and balanced 100 ohm coming out.

It's actually fairly simple, and can be accomplished with a few modifications. First, break the connection between T6 and C20, then connect your power line to C6, Q6, etc. to complete the supply connection. Done.

Looking at the output side of T6, break all of the shown connections. The upper terminal of the upper winding is your + output, and the lower end of the lower winding is your - output. Connect the lower end of the upper winging and the upper end of the lower winding to ground. Done.

The collectors of Q3 and Q4 will now see load impedances of 200 ohms instead of the original 400 ohms, so the power gain will be reduced by 6dB.


Chris Trask
N7ZWY / WDX3HLB
Senior Member IEEE

Hi Team,

I'd like to try out one of these amplifiers on a 1.8m aluminium loop I have built. Not sure if the designer Chris Trask himself has time to answer questions right now, but I thought I'd put them out on the mailing list in case anyone else could answer as well, and others might be interested in the answers anyway.

The loop I have built has the feed point at the top, and the balance point at the bottom is grounded to earth. It's up that way to get the business end as far up as possible. The bottom part is actually strapped to an alloy pole that is clamped to the centre pole of the old rotary clothesline out the back of the house. Hopefully that's fine, although she who wears the pants isn't totally impressed because it removes the "rotary" function out of the rotary clothesline.

I'm getting fairly good results with the lz1aq amp I have installed at present, but have IMD problems with BCB stations. I'm interested in 0 to 30MHz, so would rather avoid a BCB filter. The plan is to orientate the loop so the 2 local AM BCB transmitter sites are sitting in the null. (~90 deg at 2km and ~60 deg at 5km)

But my feedline I use is a run of Cat 5 ethernet cable, with one pair carrying the signal and the other 3 pairs sharing the +V and 0V load. So I need to reconfigure the amplifier's T6 output transformer for separate power feed, and balanced 100 ohm coming out.

Suggestions gratefully received.

Andy
ZL3AG

good luck ! I would like to suggest adding a notch filter..i have one on my old Drake R-4b. It works so well it's my all time favorite reciever. de Mike, N9LSD

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Today I took the 4 foot tunable loop antenna down and am in the process of putting up a "Low Noise Vertical (I hope ;-)



I put the loop up in 2012 as an experiment in the hopes that I could null out interfering beacons and add to my beacon score. ? It was a big disappointment though.? Yes, it did pick up beacons OK, but the nulls were very poor.? I first tried connecting the fet pre-amp to the high side of the tuned loop, but for all practical purposes there were no nulls.? I suspect that the "antenna effect" of the unbalanced loop, along with environment (just above a sheetmetal roof)? was the main problem.? Later I disconnected the pre-amp from the high side of the tuned loop and used a single pickup turn to the pre-amp.? Yes, there was an impedance mismatch, but that shouldn't have affected nulls, just the gain.? The "Q" was high as the varactor tuning was very sharp. . .

Well, that worked better, I could get shallow nulls (around 10dB or so) on some beacons, but not others.? Not good enough to sneeze at, or even to actually use the thing as the "active whip" could hear most of the weaker beacons much better.

So today I took it down so that I could install a 30 foot "low noise vertical" (I hope) in it's place.? I figured that I'd offer to GIVE the loop to somebody IF they wanted to experiment further with it.? Well, that didn't work out!? As soon as I lifted it and the rotator off the push-up pole it got away from me and went crashing to the ground some 15 feet down!? The result was a crumpled mass of PVC pipe and tangled copper wire.? The thing literally came apart at every glued & screwed joint!? It landed top side down and the weight of the rotator and metal TV mast probably didn't help preserve it any.

Anyway, after that little escapade I went ahead and installed the vertical section on the top of the Push-up pole.? It consists of a Hustler MO-3 mast section (aluminum) with an 80 Meter resonator and stinger mounted on it (I figure that the inductance of the coil MIGHT help a bit).? That is mounted on top of about a 7 foot piece of 2 inch PVC pipe, sitting over the top of the push-up pole.? There is a 20 foot section of 5 conductor 18ga rotator cable coming down at an angle from the bottom of the Hustler mast to an insulator at the roofline of the mobile home (angled to get it away from the metal push-up pole.? The total length is right at 30 feet and gives me a 30 foot vertical above the roof.? The matchbox containing the toroid (about 80:6 turns or so) will be mounted right at the roofline and provide the balanced output running into the radio room.? The primary side of the toroid will be grounded to an 8 foot ground rod separate from all the station grounds. ?

Tonight I'll wind the toroids (80:6 antenna section and 1:1 turns in the shack), put them in suitable housings, and hopefully install that tomorrow.? I'm to "bushed" to do any more today.? At 70 I'm almost too old to be running up and down ladders and shoving those poles way up in the sky, lol!? ?

The toroids I'm using right now.? They're "unknowns" from a switching PS, seem to work well at LF, but later I'll purchase a couple of new ones with known characteristics.? It won't be too hard to change them out at a later date.

-- 
73 de Phil,  KO6BB
  (Web Page)

RADIOS:
Grundigs:    S-350 (~2006) &  G6 (~2011).
Heathkit:    GC-1A "Mohican".  Analog Solid State (circa 1965).
Icom:        R-75 Receiver with 2 Cascaded 250Hz CW Filters.
Icom:        R-71A With 500Hz CW filter (circa 1986).       
Icom:        IC-735 HF Transceiver (circa ~1990).
Radio Shack: DX-380 digital portable (circa ~1990).
Zenith:      Royal-7000 Transoceanic Analog Portable (circa ~1969).

ACCESSORIES:  Homebrew LF-MF Pre-Amp, MFJ-993B HF Auto-Tuner.
              Homebrew 6 Hz Audio Filter.

ANTENNAS:  88' Long Ladder-line fed dipole at 35 feet AGL.
           Active Mini-Whip at 36 Feet AGL for LF/MW.
           4 Foot/side Tuned Rotatable Loop at 15 Feet AGL for LF

Merced, Central California, 37, 18, 37N   120, 30, 6W CM97rh

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Good evening Dick, I was outside today trying to get a good pic of the building and balcony but the weather was not co-operating. It was snowing so bad that the building really was not usable in the pic. It's now getting dark so will have to wait until tomorrow.
Mike

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