MW Loop Source Book

Compiled by Steve Whitt


Disclaimer: The Medium Wave Circle has no financial connection with any of the manufacturers or suppliers of the products shown on this page, nor do we endorse any product over another. The information on this page is provided for guidance only.


One of the pre-requisites for effective MW reception is a good antenna. Ideally the antenna should be located outdoors away from sources of local electrical interference (increasingly prevalent these days from electrical devices in homes).

Ideally the antenna should have directional characteristics meaning that it can enhance signals arriving from one direction whilst rejecting others from another direction. That way the antenna can help separate a desired signal from unwanted interference.

In the real world convenience and space often limit the possibilities for antennas, but fortunately the “loop antenna” is a very effective and convenient MW antenna. Every MW listener should have one even if they have larger outdoor antennas because a loop remains the simplest way of direction finding an unknown signal and nulling out an undesired signal.

MW loops antennas make good hobby projects and a simple loop can be built easily and cheaply. More sophisticated units can be built or purchased. But read reviews and check out manufacturers literature first; some loops are distinctly better than others.

AOR LA-380
AOR LA - 380

 

AOR LA-320
AOR LA-320

 

Currently available loops

All external links will open in a new window.

Model Features Indicative price Manufacturer/Supplier
Select-a-tenna: 541 I,P,T, • $59.95 Intensitronics Corporation, PO Box 28 Ashland Winconsin 54806 USA Tel: 800 382 4155 Fax: 715- 685 - 0474
Select-a-tenna: 541-M P,I/D,T, • $69.95 As above
Select-a-tenna: 541-S A,T,R,I/D,• $189.95 As above
Advantage - Indoor AM Antenna P,• $59.95 (sale price $39.95) Now marketed by Audiovox www.audiovox.com
Available from C Crane Company Inc. http://www.ccrane.com/antennas/am-antennas/terk-am-advantage.aspx
Active Loop Antenna ALA 1530 (aluminium) A,B,D,O,S,• £159 Wellbrook Communications The Farthings, Beulah, Llanwrtyd Wells, Powys LD5 4YD. UK Phone: 01591 620316 International Tel: 44 1591 620316 www.wellbrook.uk.com   
ALA 1530 (polyethylene) A,B,D,O,• £159 As above
ALA1530S (higher spec) A,B,D,O,• £200 As above
Indoor Loop Antenna LA5030 A,B,D,• £159 As above
Active Loop Antenna ALA 100 (large aperture) A,B,D,O £139 As above
Kiwa MW Air-Core Loop Antenna A,D,E,R,T,• Recently discontinued Kiwa 503 7th. Ave. N.E., Kasson, MN 55944 USA 507.634.6134 phone/fax kiwa@wolfnet.com http://www.kiwa.com (also sold via Universal Radio)
Kiwa Pocket Loop A,C,T,• $195.00 As above
PRM - Pocket Regeneration Module (other accessories also available) A,R,T $48.00 As above
AM Radio Loop Antenna T, I, P,� $48.75 MTM Scientific, Inc P.O. Box 522, Clinton, Michigan 49236, USA http://www.mtmscientific.com/loop.html
Quantum QX Loop v2.0 A,R,D/I,E,F,T,ƒ $199 Gerry Thomas KB4JFM, Radio+ Electronics, 3635 Chastain Way, Pensacola, FL 32504 USA; radioplus@bellsouth.net 904-434-3635 http://www.dxtools.com
Quantum QX Loop v2.0 + A,R,D/I,E,F, T,ƒ $239 As above
Palomar LA1 amplifier base + BCB Ferrite Loop element (other elements for LW & SW available) LC1 inductive coupler A,D,E,F,T,ƒ Base amplifier $135 LF element $135 VLF element $150 LC1 coupler $49.95 Palomar, Box 462222 Escondido CA 92046 USA www.palomar-engineers.com Phone: 760-747-3343 FAX: 760-747-3346 or order via Universal Radio, Inc
LA-320 comes with SW elements 320L longwave 320M medium wave A,D,F,T, ƒ,• Product discontinued by loop elements may still be available from Universal Radio AOR UK Ltd, Unit 9, Dimple Road Business Centre, Matlock, Derbyshire DE4 3JX England Tel: +44 (0) 1629 581222 Fax: +44 (0) 1629 580070 www.aoruk.com  http://www.universal-radio.com/CATALOG/sw_ant/3753.html
LA-380 SW & general coverage loop A,D,T,♦ £189 As above
ADDX MW-2 Mediumwave 40cm Loop + optional amplifier P,T,• Current prices not available Charly H. Hardt Funktechnik und Electronic Edelhoffstrasse 70, 42857 Remscheid, Germany Tel.: (0 21 91) 80 59 8 Fax: (0 21 91) 83 55 7 http://www.charly-hardt.de/eigen.html
ADDX MW3 travel loop P,T,• Current prices not available As above
Grahn Magnetic Loop GS2-SE base station 350DM, (less the MF converter 228DM) Ferrite modules: 69-109 DM, loops between 119-248 DM. Grahn Spezialantennen, Stuttgarter Strasse 215, 73230 Kirchheim/Teck, Germany Tel.: (0 70 21) 97 98 50 Fax: (0 70 21) 97 98 52 http://www.grahn-spezialantennen.de
Grahn Magnetic Loop GS3-SE (base) ML2 MW module 299Euro for base 149Euro for ML2 149Euro for VLF2 69Euro for LW1 As above
A-LOOP-TAM P,I,T,• A$60 Contact Paul and Louise Karlstrand, Victoria, Austrailia. http://www.amradioantennas.com E-mail:
A-LOOP-HI-FI B,A,S,D,• A$130 As above
Haverkamp Easy Loop A,C,• No current info available Ingenieurbuero G. Haverkamp, Spiessgasse 31, 64665 Alsbach-Haehnlein, Germany Tel.: (0 62 57) 41 17 Fax: (0 62 57) 41 17
Martens Mediumwave Loop A,R,T,♦ No current info available Juergen Martens Nachrichtentechnik, Zeppelinstrasse 38, 72800 Eningen, Germany Tel.: (0 71 21) 8 23 36 Fax: (0 71 21) 88 02 20

Data and prices checked February 2007 but always check with suppliers before ordering. Additional delivery charges are usually made.

Key: (information on features is included where known)

* A= Active, powered amplifier (needs batteries or other source of electricity)
* B = Broadband loop – no tuning necessary
* C = collapses easily for travel
* D = Direct cable/plug to receiver (essential if receiver does not have its own internal ferrite rod)
* E = Elevation adjustable (tilting) as well as rotatable
* F = Ferrite rod element (otherwise air cored)
* I = Inductive coupling to ferrite rod in receiver (see D above)
* O = Outdoor compatible (otherwise only intended for indoor use)
* P = Passive (no power needed, un-amplified)
* R = Regenerative amplifier for ultra sharp tuning
* S = Screened element (to reduce local electrical noise pick-up)
* T = Tuned (usually a tuning capacitor tunes loop to resonance)
* ??• = shape of air cored loop; ƒ = ferrite rod

 


Palomar LA - 1

 

Terk
Terk AM Advantage

 

Obsolete Loops

You might find loops and aerials on the second hand market from manufacturers no longer in business today. Many were made by hobbyists in small volume. Examine second hand loops for mechanical integrity and check if the electronics is repairable should it be faulty (some makers encapsulate the amplifier in epoxy resin). Obviously try the loop out, but not in a high interference location such as at a “bring & buy” stall at a radio show or ham fest (you’ll probably only hear the fluorescent lights and computers all around you!). Information in the following list may now be seriously out of date:

EGZ Costruzioni Elettroniche, CP 56, 27026 Garlasco, Italy
LPF-1 very large aperture ferrite rod (110cm long) ; 3 versions; VLF, LW & MW; 10kHz-2MHz tuned

Deutschlandfunk Cologne, Germany Magic Disc; passive pre-tuned loop issued free by DLF to listeners; 1269kHz only; size & shape of 12inch LP record

Eldon Electronic Enterprises, PO Box 713, Port Coquitlam, BC V3B 6H9 Canada Tel: 604-532-0170
EEE-195 desk top ferrite rod "loop" 540kHz-1700kHz; $Can 150
EEE-195TL desk top "tri-loop" 540kHz-1700kHz; $Can175

Fala Electronics, PO Box 1376, Milwaukee WI 53201-1376; Tel: 414-671-5203
Model 1701 tunes 530-1700kHz $48 + $5.50 handling

Forster Radio Technology, PO Box 2356, Reading RG6 7FQ Tel: 01734-261972 TL Loop; 90cm diameter active broadband loop 10kHz-30MHz; was £79

Graham Maynard, 16 Woodford Avenue, Newtownabbey, N. Ireland BT36 6TL, UK;
ATL-3 indoor spiral loop 140kHz - 32MHz optimised for MW + tropical bands
ALN-2 improved ALN1
ALN-1 large outdoor fixed loop 100kHz-17MHz with in-built local noise nulling
ATL-2 30inch square active tuned loop 50kHz-4.44MHz in 6 ranges (was £68)

Hewlett Packard Loop antenna for the HP117A VLF tracking receiver

Kiwa MW Air-Core Loop Antenna

Kowalski Loop The Kowalski Loop is an amplified MW ferrite rod type loop. It was built and sold on a very limited basis by former National Radio Club member Paul Kowalski. He only built them for people he knew, so there are not very many of them out there. The antenna consists of a base, amplifer unit, coil, and ferrite rod. The nulling capability, is definitely inferior to the Radio West Loop.

Lowe Electronics, Chesterfield Road, Matlock, Derbyshire DE4 5LE; Tel: 01629-580800; http://www.lowe.co.uk
UL1000 small desktop loop 500kHz - 30MHz

McKay Dymek, 111 So. College Av, Claremont CA 91711 USA; Tel: 1-800-854-7769
DA5 shielded MW ferrite rod antenna; amplified; adjustable elevation; tuned

Mike B Evans, 120 Loughton Way, Buckhurst Hill, Essex IG9 6AR, UK
Amplified box loop; ~£35

Phasetrack Ltd, 16 Britten Road, Reading RG2 0AU, UK; ? 01734 752666
Liniplex Loop outdoor broadband amplified loop 50kHz - 30MHz; ~£400
Unique patented design; patents have run out now

Radio+ Electronics, 3635 Chastain Way, Pensacola, FL 32504 USA; Tel:904-434-3635
Models: tuned ferrite rods; Quantum Loop (was $165) and Q-Stick, QX and QX Pro

RSM Communications (Ray Moore), Box 1046, Key Largo FL 33037 USA
RSM-105 1m passive square loop for precision direction finding, models for 150kHz-7.6MHz
Radio West Loop; The loop consisted of a base, amplifier unit, coils and a three piece ferrite rod that was 15" long. It was fully rotatable and tiltable. The loop was produced from the late 70's - early 90's. (It was superior to the Space magnets; inferior to Quantum Loop 2 & Kiwa Loop).

Sanserino Loop (by Ralph Sanserino)
Amplified ferrite rod loop; 2 coils 540-1700kHz & 1700-5000kHz

Torus Tuner was made by Edek Electronics, 622 Deer Park Avenue, Oakland, MD 21550 USA Tel: 301-334-5228 edek@mail.gcnet.net

VEA (E C van der Ecken and Eric Force), Sicklerville, NJ, USA; eforce@dobe.com
Model VEA MW-1812: Tuned Inductively coupled loop $79
Model MW-1812VE: Improved version of MW 1812 + direct receiver connection.
24 in high x 12" wide loop Discontinued Sept 1999

Worcester Electronics Laboratory,
Models SM-1 and SM-2 Space Magnet (popular in 1970s)
Shielded 12 inch ferrite rod with 2 stage pre-amplifier

Worldcom Technology, 1118 Raymond Avenue, Ft Pierce FL 34950 USA; Tel ; 407-466-4640
Model NXL 250A = Amplified shielded loop, standard model covers 540kHz - 30MHz, choice of 20 or 12 in loop and 500-1700kHz MW version; MW version was $85

 

Wellbrook LA5030 Wellbrook 1530
Wellbrook LA5030 & Wellbrook 1530

 

 

Questions to ask when buying a loop

Physical: how big? how easy to rotate? is it tiltable? how stable are mechanics for accurate nulling? indoor or outdoor use? Is a support provided or stand or a turntable needed?

Connection to receiver: direct coax cable to antenna socket on receiver? direct inductive coupling to internal ferrite rod of portable receiver? indirect coupling wand to link to receiver's whip?

Power: self contained batteries? on/off LED indicator? mains power adaptor? battery life?

Amplifier: Differential amp.? low noise design? overloaded by strong signals? is gain controllable?

Low intermodulation or High Intercept Point essential for broadband (un-tuned loops).

Loop: air core or ferrite? dimensions? collapsible for transportation? electrostatically shielded winding? switchable tuning ranges? reduction gearing on tuning capacitor for precision tuning?

Overall Performance: bandwidth (Q) of a tuned/resonant loop? dynamic range or intercept point of a broadband amplified loop? Accuracy and symmetry of nulls?

Cost/availability: includes cables to connect to receiver? includes power adaptor? includes postage/tax? ex-stock or custom built? how long for delivery? Shipping charges – particularly overseas.

The best loop choice for a given DXer will be determined by the receiver, location, and type of DXing to be done. Sensitivity is not critical for night use, except in auroral conditions or at very remote quiet sites. Strong signal handling is very important at an urban site nearer high power transmitters, but less so in the country. Active loops are much more likely to generate inter-modulation distortion products in the urban environment. The physical size of the loop is important to those who take it "in the field" or who have very small DX "shack" rooms. Good nulling is important to most of us, except perhaps for the steel-frame apartment dweller, who can only receive stations with the loop pressed up against a window. And a not-insignificant factor is, of course, price.

Select-antenna 541 Select-antenna 541S
Select-a-tenna 541 & Select-a-tenna 541-S

 

Footnote

If you spot any errors or omissions we’d like to know about them. Please E-mail us to let us know.

Grahn GS3-SE Kiwa Pocket Loop
Grahn GS3-SE with ML2 module & Kiwa Pocket Loop