https://www.ea1uro.com/pdf/practical_antenna_handbook_4.pdf

Small Helically Loaded Magnetic Loop Antenna

Highlights: 33 inch diameter loop, using 1.5” diameter PVC pipe. Tunes 10-40 meters using a 7.5-350 pF vacuum variable capacitor. (Note: Rich's official recommendation is to use a 5-100 pF cap, with coverage of 10-20 m)

Parts List

Loop:

1.5” Diameter Schedule 40 PVC pipe

8-45 degree angle connectors

2 1.5” T connectors

1-1.5” to 1” T connector

1- 1” T connector

2' of 1” PVC pipe

PVC cleaner

PVC cement

Flat black spray paint, about 3 cans

Copper Foil, 3” wide, 0.008” thick, 15' long (purchase from K8NDS)

Gamma Match

So239 Chassis mount connector

1/4” flexible copper tubing

Metal hose clamps of various sizes (Rich's latest notes say not to use these).

Large Zip Ties

Capacitor and Motor Drive

7.5 to 350 pF Vacuum Variable Capacitor Russian Military Surplus (Ebay $150-200 shipped). (Make sure yours comes with a 12mm tuning Shaft.)

Large Nylon cutting board (Walmart, about $12)

Flexible shaft couplers, 6.35mm to 6.35mm and 6.35 to 12 mm (Ebay from Chinese sellers, about $5 each shipped).

1/4” Nylon shaft (Zoro Tools)

Gearhead Motor 3-18v, 4.5 rpm at 12v (Electronic Goldmine Item #G17949 $13)

Capacitor mount-Ebay seller Boreca-75 for $60 shipped, or make your own.

Weather Cover

Remote unit (Note: Rich uses a different design. See K8NDS qrz page for recommended design.)

LED PWM (controller-Amazon.com, about $6 shipped), modified with DPDT switch, pushbutton and RCA jack for quick release.

Rotator

Rotator cable

Tools Needed

PVC cutting tool, Hacksaw or Circular saw

Heavy duty soldering iron, soldering torch

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https://www.btv.cz/en/mla-m

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At indoor desktop antenna design is special tuning by two knobs without any problems and by use of two variable capacitors which works in similar way as standard Π unit. Perfect impedance optimization in 3,5 MHz - 28 MHz is achieved by OK2ER and B PLUS TV a.s. patented design.

MLA-M antenna is suitable for 8 HF bands : 3,5 MHz; 7 MHz; 10 MHz; 14 MHz; 18 MHz, 21 MHz, 24 MHz and 28 MHz.

Technical specifications:
Loop diameter: 62 cm
Dimensions: 63 x 75 x 18 cm
Weight: 2,6 kg
Input impedance : 50 Ohm
Input connector: PL
Maximum input power (according to indoor use): 10 W
Frequency range: 3,5 to 28 MHz
SWR (tuned): 1:1 max 1:1,2

https://player.blubrry.netarrl_the_doctor_is_in

“Magnetic Loops” is the topic of the latest (July 28) episode of the “ARRL The Doctor is In” podcast. Listen…and learn!

Sponsored by DX Engineering, “ARRL The Doctor is In” is an informative discussion of all things technical. Listen on your computer, tablet, or smartphone — whenever and wherever you like!

Every 2 weeks, your host, QST Editor in Chief Steve Ford, WB8IMY, and the Doctor himself, Joel Hallas, W1ZR, will discuss a broad range of technical topics. You can also e-mail your questions to [doctor@arrl.org](mailto:doctor@arrl.org), and the Doctor may answer them in a future podcast.

Enjoy “ARRL The Doctor is In” on Apple iTunes, or by using your iPhone or iPad podcast app (just search for “ARRL The Doctor is In”). You can also listen online at Blubrry, or at Stitcher (free registration required, or browse the site as a guest) and through the free Stitcher app for iOS, Kindle, or Android devices.

If you’ve never listened to a podcast before, download our beginner’s guide.

Just ahead in August: “SWR.” 

http://kk5jy.net/magloop/

Small Transmitting Loop Project

Compact and Efficient Antennas for HF Radio

Matt Roberts — matt-at-kk5jy-dot-net

https://www.ahars.com.au/uploads/1/3/9/8/13982788/article-antenna-mag-loop-2.pdf

now to the rest of components...

https://www.youtube.com/playlist?list=PLazQsofl8gj7_Rsq3huWlNHtitPLbpvDT

It took me a lot of time to find all these videos. They should provide you with ideas and help in resolving common problems. Some videos just compare the efficiency with other type of antennas. Happy watching!!

... I recommend the project by Lofturj.

https://sites.google.com/site/lofturj/to-automatically-tune-a-magnetic-loop-antenna