DIY Magnetic Loop Antenna

Operating as a Ham in the city can definitely pose some challenges. I mean, think about it! With the increasing amount of wireless & digital communications found on the...

Operating as a Ham in the city can definitely pose some challenges. I mean, think about it! With the increasing amount of wireless & digital communications found on the airwaves now and all of the interference caused by electromagnetic radiation? Your typical wire antenna in the city just might not cut it! At least mine didn’t! So after hours and hours upon surfing the net, I kept reading about an option called the Magnetic Loop Antenna. So many other hams were swearing by their performance. A few redditors even noted that they were able to work the entire globe on just 5 watts on one of these things! The magnetic loop antenna is able to suppress a lot of the noise coming in, not only due to the narrow bandwidth, but has something to do with the physics of how one of these work. This is also a good option for hams who might be restricted due to living in an apartment, or living in an HOA, or a high rise condo! I stumbled on an article written by KF5CZO (DIY Magnetic Loop Antenna by KF5CZO), hey another KF5! It was destiny to find the article, lol. Here was a very well written article on how to make a DIY MLA (magnetic loop antenna).

Doesn’t look too hard right? Well, i’ll just consider this practice, and if for some reason, it turns out to be a ridiculous failure, I can always rely on companies who have already perfected the process (hence why their product is still sitting on shelves).

Parts list:
1. 1/2 in. soft copper tubing (comes in 10 or 20 ft. pieces usually @ Lowes or Home Depot)
2. 8 ft. 2×3
3. 8 ft. 2×4
4. MDF plywood piece (I had scrap laying around, you can use whatever will form a solid base)
5. 1 variable capacitor (mine has a rating of up to 350pf – generally about 500-600 is what you want if your going to run higher power), purchased from eBay
6. 1 SO-239 chassis mount
7. 1 24″ piece of 10AWG copper wire stranded
8. Electrical Solder & flux (to aid in melting the solder & copper together)
9. Screws
10. 1 ABS enclosure (I like to keep my electronics out of the elements – including the dust in my house)
11. Electrical tape (I use 3M Super 33)
12. 1 small piece of plexi glass to mount your SO239 to.

Tools needed:
1. Soldering gun
2. Drill & bits
3. Saw
4. Tape measure
5. String
6. Clamps
7. Hammer
8. Wire strippers or knife
9. Small propane torch (to melt solder to copper)

These are the items that I used, they can be substituted for whatever you have, or you think might work with this application, please just remember safety first! If you’ve never attempted soldering or constructing something like this, don’t be afraid to ask for help! Usually you’ll have to get two folks to assist while your doing the detailed soldering work up at the variable capacitor, just helps to have an extra set of hands! Adventure starts tonight!

(Edit: I’ve had a few folks email me asking about the instructions from these other hams, here are the links: KF5CZO- http://www.cvarc.org/tech/magnetic_loop_antenna.pdf & KK5JY- http://www.kk5jy.net/magloop/)

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HF AntennasMagnetic Loop
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