My Low Cost Magnetic Loop Antenna For 10-12 Meters

I decided to build a magnetic loop antenna that would cover the ham radio frequencies from around 20 to 30 Mhz so I could use it on portable with my Magnum 1012 hand held radio. This is what I come up with.
Since those bands are heating up now with the progress of the new sun spot cycle, this should be fun to use with the low power output of the radio and should make a better antenna than the duck antenna since it is a very high-q tuneable antenna. This antenna would also work well for the 11 meter CB band, great for anyone with very limited space for antennas or for portable operations.

[@Pivotal_Moment]

Stumbled across this video all these years after it's been initially posted. And its the simplest, straightforward, and most accurate explanation of magnetic loop antennas. Thank you for this!!

[@MundoQRP]

'm riding a loop for 7-30 mhz but I want to use more power in transmission around 100 watts. Checked using the vacuum capacitors 10 to 500pf but the price is way high. Variables have the common problem of isolation. Found very interesting use of a VU meter for checking the output energy of the antenna. If you use a normal variable I will use a vernier adjustment knob. Congratulations for the video!

[@argentogoldspier5211]

Excellent clear interesting videos. I am going to make a magnetic loop soon for fun. Here is a web page I found for measurements www.66pacific.com/calculators/small_tx_loop_calc.aspx from what I can gather 27MHz with 19mm Copper Tube Between 1.3 to 2.69 meters Circumference, 28 MHz Between 1.3 to 2.6 meters Circumference , 3.5MHz Between 10.4 and 20.8 meters Circumference, 7 MHz Between 5.2 and 10.4 meters Circumference, 14MHz Between 2.6 and 5.2 meters Circumference, 21MHz Between 1.73 and 3.46 meters Circumference and like you say 1/5 smaller is the driving loop. They say the loop radiates from side on but yours gave best when the circle or face was in the direction of the field strength meter.Your soldering iron brings back memories of when I used that type back in the early 80's. Nice to see a blue Weller again. Thank you

[@UBIQUITAR]

KEØNJG. VERY VERY NICE. will be building as well. Grab your tools and get to work. Build it and show off. Great fun

[@RadioHamGuy]

Since it is hard to explain in words probably the best thing to do would be to search on KZbin here for "how to install a pl259 connector" or the type connector you have, I just did a search and see there are a lot of videos that will show you how to do that much better than words can say here so I would recommend that. You just want to make sure the center wire and the outer braid on the cable are not touching each other at all in the connector or it will be a short and will not work.

[@RadioHamGuy]

Thanks, well, the spacing is not critical, closer is probably better as long as they don't touch each other but yes, mine is probably about an inch or so apart. Of course you wouldn't want them several inches apart but nothing critical about it from my experimenting anyhow.

[@RadioHamGuy]

I am not really all that familiar with antennas for phone use I guess, I do know they make cell phone repeaters for use in buildings or homes with very weak signals, sorry I can't help more, maybe someone else can comment..

[@RadioHamGuy]

I can try and give you some pointers if you send a personal note and see how I can help..

[@buettstube]

Hi. What kind of diode i need exactly?

[@RadioHamGuy]

A small glass germanium signal type like a 1n34a works well. You don't want to use the rectifier silicon type diodes that are usually black in color, they will not work well.

[@buettstube]

RadioHamGuy Thank you! Should be no problem to get one here in Germany. ;-)

[@radiosification]

nice video, are you going to make one where you show some contacts?

[@CamoCrabby]

I was going to make a more detailed video about the loops I made. However, you beat me to it . . . and did a much better job! I love the meter addition, and I know what part I'm going to look for next ;~) For those thinking about making a loop, just go for it. Very simple project, and the most difficult part to find is the variable capacitor (easily available from a parts radio or eBay). 73, KC8JZO

[@user-uv4xe3cq2y]

Great presentation, the greatest audio ever! Thanks!

[@pu2clr]

I do not get tired in watching this video. By the way, accidentally I deleted your comment on my KZbin channel about my "Automatic Antenna Tuner for QRP". My apologies. It would be an honor to have your comment again there. 73's. PU2CLR.

[@choppergirl]

I made a loop antenna today with a bucket, wire, and a variable cap from an AA5 and a swtich, and it totally does nothing. I think I need to double my loop for my 1 foot diameter bucket.

[@zonacountrytv]

Hi Larry, which is the pF value of the capacitor variable you use in this video? sorry i m not speak english.

[@1903A3shooter]

Worked most of a week trying to get my loop to act like it should. At 6 ft. the best I got was 22 Meg.Hz swr of 1, resistance of 50 and reactance of O. not bad but at wrong freq. as I reduced the value of Cap the freq. went up but so did the SWR and Reactance. Tried many Caps even a Butter Fly. took the antenna out side to get it away from metal in shack but no change. Finely gave up. Jest saw another way to feed the loop so I might try that. W4GSM

[@h2otek312]

Curious that these still seem popular. I hear that routing the coax can be critical with these since the majority of actual radiation is via the feedline. The "antenna" proper is effectively just a decent tuning section, according to most of the best antenna engineers. But hey, if it works for you isn't that the bottom line? Who cares what the theoretical shortcomings might be when you can still make contacts?

[@mark33545]

I ran into tons of noise with my fan dipole in the attic, I was able to make a few contacts a few hundred miles away but I get around s9 noise so its very difficult. I am now going to try a magloop instead, I ordered a quality variable capacitor and hoping it might solve my issues.

[@namdogtag]

Nice video! I Just got a Magnum 1012 radio last week with accessories ..... I went to HRO afterwards and got the MFJ 1810T telescoping antenna (this antenna was actually made for the Yaesu FT 817) for 10 meters......the 10 meter band hasn't been open since I got the rig and antenna to really test her out....that loop antenna looks very interesting!....Do you have any feedback regarding the MFJ 1810T performance?.....thank you and again Great Videos!. 73 ... K8ESE Hal

[@cowboy6591]

As for the bloopers at the end. Get a teleprompter!! There cheap now. Nice job sir, the prices for pre manufactured ones are an immoral rip-off!! This DIY makes sense.

[@masken72]

i am tottaly crasy can jo maby make some kind of esy help file to bild it i am using 27.555 but i cant have anny kind of antenas outside very nice loop can you please help me to make one ????

[@combatwombat71]

@RadioHamGuy Some low band loops, 80m etc. with a high Q are not wide enough bandwidth to even accommocate an SSB signal! I built a loop with a vacuum capacitor that will do from 30m to 10m, it's about 1.4m dia. 73 VK2GOM

[@lifeonewave]

hello friend. how i can make an external antenna and a receiver which can give signal of mobile phone network without connect with mobile phone. because no signals available in my room

[@VE7QRZ]

Thank you for this video, and this is the best explanation I have come across for this type of antenna. 73

[@muhammadslwaey8829]

Greetings to you dear friend, how can I make a very powerful external antenna .... I went in the past few days to the old used radio market and got one with a variable metal capacitor like the one you are explaining on now, in addition to the ferrite column and the wire around it and after removing it From the old radio, I did not know how to connect it to make an antenna for the radio, knowing that there are many and many videos on KZbin explaining this, but I am confused about the correct way, please help

[@phillipneal8194]

Excellent presentation. Thank you. You kind of focussed on transmission, how do I tune it for reception ?

[@RadioHamGuy]

I have not tried over about 25 watts or so into this loop and not really sure what it could handle but it would mostly depend on the variable cap used. I just use these loops with lower power output. Sorry that is about all I can tell you, kind of experimental for me with power levels. It might handle more. I would guess that it would just start to arc over on the cap with too much power.

[@RadioHamGuy]

In the configuration it is in, the most energy transfers from the primary loop to the secondary larger loop, so that is most efficient, turning the smaller loop or moving it farther away would make for less signal coupling so it would become less efficient, however I have not really tried that experiment first hand, so if anyone has other ideas please comment and correct me I guess..but I think that will be the case.

[@MrRudywing]

I made it for the 11 meter band, why is it bigger than yours? can you share the formula how to calculate it? i have tried, but the swr is high ...

[@RadioHamGuy]

Hi John, thanks. I took a look at that on ebay and that is called a cubical quad antenna, it works much different than the type of magnetic loop I have on my video, but they work very well also, they are a type of beam antenna, there is a yagi type with the straight elements, then the quad like that one you are looking at. He has a video also, you can see the link at the bottom of that ebay page. If you search for quad antennas on google, you will find a lot of info. Can be square or round.

[@RadioHamGuy]

@johnkc8jzo Thanks for the comments, yes, the loops are actually very easy to build and fun to play around with and it is interesting to see how the loop really does tune and work. Would probably be a good project for a ham club or something as a learning project...

[@PatAutrey]

Can you please clarify which direction the signal goes from the loop does it imitate outward perpendicular or does it go by directional based on the way the hole is pointing in other words how do aim it?

[@RadioHamGuy]

@fordbroncodave I think it helps some with bandwidth to use larger diameter pipe but not a great deal, they are still very narrow, this one will work about 20 khz bandwidth or so without re-tuning.

[@RadioHamGuy]

It is within an inch or so of that, but it is not real critical if you are off a few inches or so, the tuning capacitor will still adjust for frequency ok..

[@centu2000pr]

nice for apartments or just to do radio mobil. funny bloopers............ bla bla bla ja ja ja. good work.

[@CB-RADIO-UK]

Thank you for sharing and explaining things so clearly. Enjoyed the video. Subbed.

[@RadioHamGuy]

I have not had any first hand experience with the MFJ antenna but would think that it would work well for that purpose. Yes, 10 meters has not been in that great a shape lately so it is hard to test things out. Let me know what you think of it when the band is in good shape again if you want, would be interesting to see how that antenna works out.

[@RadioHamGuy]

Yes, that should work out well then, have fun experimenting and if you search out magnetic loop antennas on the internet you will find a lot of good info also as you may have already done. Thanks again and good luck.

[@RadioHamGuy]

Yes it can be used for CB radio, great for limited space or portable use. You would probably have to tweak the tuning to cover top to bottom of the band but if you just hang out on certain channels you could just mount it and leave it in one spot if you wanted.

[@RadioHamGuy]

Thanks. Sounds great, yes, a loop might be a very good solution for apartment use, I would think much better than a ham stick since you need good grounding on them. Let me know how it works out if you build one. At least they are cheap and easy to build and try. If it works out, you might want to either add a motorized tuning device or purchase one that is all set up with that to make tuning easy and faster.

[@RadioHamGuy]

I would probably use a small capacitor meter that will measure capacitance, they look like a digital dvm. Maybe others could leave some suggestions on that also..

[@RadioHamGuy]

Good luck with the experimenting, that is half the fun. Hopefully you will be able to get a loop going, they do work well for the size. 73...Larry

[@RadioHamGuy]

@8592291613 sounds great!

[@RadioHamGuy]

Thanks, I may do a video on a 40 meter loop in the future as I think I will need one for a qrp rig I am building. You do not want to use an external antenna tuner on a magnetic loop since the antenna needs to be tuned by the variable capacitor attached right to the loop. 73..Larry

[@CBRadioWayBack10-4]

10 to 12mtrs, so he means 11mtrs CB really then :)

[@ВячеславГороховатский]

Большое спасибо за видео ! Какие размеры ? US7ITC 73!

[@RadioHamGuy]

I cut a slit in the pvc for the flat part of the small loop to fit into, I just cut a little less than half way through. Holds it in place but I also used some hot glue around that to help keep in place.

[@RadioHamGuy]

That sounds very good, I will check out that website and take a listen, thanks for the info and also thanks for adding the links to the videos here, much appreciated! 73..Larry

[@RadioHamGuy]

Oh, I think it might be around the 50 pf range, I don't remember for sure now, but it is not critical, you can try what you have on hand.

[@RadioHamGuy]

@MrSuperheterodyne Thanks! Yes, very easy to make and works quite well for the size. Very close in performance to a dipole if done correctly.

[@RadioHamGuy]

Good to hear, good luck, should work well for you. Thanks for the comment!..Larry

[@RadioHamGuy]

Yes, that is a very good idea, I would like to do that when we get some good band conditions again on 10 meters, so I am planning on it on some future date here.

[@RadioHamGuy]

@patchcords yes, I know some people do add a servo motor to tune remotely. Great idea for mounting remotely from the shack.

[@RadioHamGuy]

@kcscarecrow sounds great, they are a lot of fun to work with and play around with..easy project.

[@applevalleyjoe]

Can you post a parts specs sheet and procedures for us to follow, please.

[@frequencywatchers]

How Do You Calculate Loop Antenna Parameters?

[@RadioHamGuy]

Thanks, yes, it could be one solution for you in that situation, sure worth trying it out.

[@happymark1805]

instead of copper tube you can use 1/2'' cellflex, it is cheap to find.

[@RadioHamGuy]

Thank you, yes, they are very easy to build and experiment with and they do work very well for the size.

[@RadioHamGuy]

Thanks! Appreciate the comments very much. Have fun with radio...Larry

[@thecobraman]

Hi Larry thats spot on buddy i must try make one top marks

[@pagansunburn470]

Where can I find a 50pf air variable capacitor?

[@RadioHamGuy]

@WECB640 Thanks, plenty of projects with no end in site here, lol..

[@RadioHamGuy]

Thanks Howard and good luck with the projects! Hope things work out well for you there. 73

[@arsbadmojo]

Do you know what property of this design makes it resonant at the target frequency? It sounds from what I've seen that the small loop is always 1/5 size of the large loop - does the large loop determine the frequency? This doesn't seem to be talked about much. I know the capacitor is going to fine tune, but I'm really only concerned with 28.0-28.5 MHz, so if I wanted to design for that specific range, how should I go about it?

[@George10767]

I have found that Magnetic Loop Antennas are very tolerant about dimensions. I have a rule-of-thumb that says the distance around the periphery should be about one-quarter the wavelength at resonance. But there is nothing precise about it. The only important things are to get the resonant frequency correct (by tweaking the tuning capacitor), and also to make the input impedance about 50 ohm by measuring the VSWR. (I would not accept a VSWR greater than 1.5). Also don't apply high power unless the the frequency is correct, otherwise you can damage your transmitter. Also with high power don't get too close, you could "microwave" yourself. (There are not enough safety warnings about this).

[@soldadodecristo9254]

HOLA PODRÍAS COMPARTIR LOS PLANOS POR FAVOR 73

[@8592291613]

thanks going to make one just like yours 73DE KS4WW John

[@1903A3shooter]

You sound a bit like "C.B. radiomagazine.com

[@fordbroncodave]

i think i want one of these! i wonder how well it would work in a large scale like 10 feet across on a platform and rotor. does changing the diameter of the larger ring pipe help with being more broad banded?

[@GordonHudson]

Thanks for this video. I built one of these years ago, but had forgotten all abut it. Just getting back into ham radio after a few years of restricted operation. May look into this idea again. 73 Gordon GM4SVM

[@OH8EFI]

What is the smallest diameter or length for main loop that I can get, even with changing to different capacitor? It would be cool to have as small as it could be to use it QRP somewhere where I may go backpacking..

[@francisd.8129]

Hi radioHamGuy, thanks for your video. I rent a flat on the third floor and the landlord has summoned me to remove my base antenna from the roof of the bulding. On my balcony there is no room for a gpa antenna! Since then I have been struggling with all kinds of antennas. I build my own inverted V! It's a good antnna, good swr etc., but transmitting with that antenna is hardI So in my search of a good antenna I came across your video. I have a few questions though. Does the variable condensator has a maximum of 50pF ?. What about scatter at my neighbors, can you tell me something about that? Will any germanium diode on the watt meter do?. thanks Francis

[@RadioHamGuy]

Hi Francis. This antenna could work for you, it will not be as good as an outdoor antenna but you could still make contacts with it as long as you do not have steel siding on the building or something that would limit your signal from getting out of the building. If you could get it on the balcony it should work quite well, I have used mine just outside my house and even inside the house. I am not sure if your neighbors would see any RFI problems or not but I am guessing not, so give it a try. It is somewhat directional so you would want to be able to rotate it by hand for best reception or to null out noise. The capacitor is somewhere around 50pf max but not critical, you can experiment with what you have and just see where it resonates at, the low and the high freq. A 100pf would work but the tuning would be a little more sharp I would guess.An antenna analyzer is a big help but not needed, just tune receiver for max noise to start with by tuning the cap back and forth, if you hear no change, it probably isn't covering that range, then try another band. pretty much any germanium diode should work fine, and the the meter is just an optional thing I added to make tuning easier but not necessary. Hope that helps and good luck!

[@epier66000]

Awesome Video... I See You Have A Motorola Mocat CB In Your Shack... Just Wondering If You Have Any Others Or If You Are Selling It I Collect Also Vintage Radios.. 73's From Cape Cod Ma. N1WCO...

[@polarbear5464]

Whats the dbi gain in 10 degrees or so?

[@skycarl]

Thanks Larry, this will be just what I need to work some qrp with my HW-8. No place outside for any antenna so this will help. Great vids, keep them rolling. 73

[@RadioHamGuy]

nice page you have and also on qrz.com, thanks..

[@vasilepop4369]

Congratulations! Wonderful video. Production quality is so great that it is a pleasure to watch it! 73 de VA6POP Vasile

[@dalemyers9265]

what size loop would you suggest for 40 to 80 or 40 to 160. also would larger diameter copper tubing be more suited for lower band freq's? larger diameter copper would make a lower band loop more sturdy in bad weather. and i can only imagine that it would be good to paint it or plate it with gold to reduce oxidation.... that is if you plan to leave it out once set up for permanent use.

[@jkbish1]

I just bought a Siltronix Comanche 1011D on line. (Of course I hope it actually works :-) ) In any case, I think I will try this mag loop idea.

[@dalemyers9265]

another great thing about the loop antennas. it being narrow banded means the antenna becomes a filter itself. so your equipment can have a certain amount of harmonics and the radiator can't effectively radiate them. then they are trapped and spent as heat.. and heat isn't that bad, when the antenna can de-ice itself. great video sir. i will be making one soon. but i first must buy a hf rig. after all these years and finally passing the amateur-extra. i have yet to work hf other than 10 and 11. 73's kf4dcy

[@DustInTheWindAZ]

Since I have only a CB radio, I have a couple of questions for variations: 1) Can it be set up without the variable capacitor (tuner) for just the CB band; and 2) Can you make it omni-directional by adding another loop 90 degrees from the original, perhaps sharing the primary coil (diagonally and interweaved?) between the two main antenna loops?

[@hainstiktok8013]

Hello sir. I am glad that I have found this video. It is really a good video. Actually, I am doing my final year project and i have searched the calculations to build this antenna. But, i couldnt find it. I hope i can learn the calculation from you, sir. Thank you. And the frequency that i need to analyse is 1 MHz to 10 Mhz . And again sir, thanks. :)

[@theodoresears4679]

My Qrm is a jammer on 27.209 and utility companies broadband. He insists on broadcasting radom music at grayline propagation time. My utility companies in my home. Are lazy about fixing to noise source. Century internet and phone company and Portland general Electric. My landowner is not willing to fix the trees on the utility wires. Please help.

[@marcomartini9239]

OK gentleman. In the case of a magloop for 11m cb, what are the types of varicaps that should work. I mean, if it is say 50pF, does it vary from like 20pF to say 80pF? please help me.

[@purplemutantas]

I tried a loop once. The capacitor I used was a pain to tune. I have a capacitor with a reduction gear that should be easier to tune. I have been thinking of making a loop antenna based on the Alex Loop walk ham. I like the idea of a loop that breaks down for transport.

[@KenWoodTS480]

Excellent ! this is far the bes magnetic loopt i have seen looks mint....BTW just wondering if these radiate same as a yagi with driven elents etc. looks to be so to me so the possiblitities are endless in construct thanks for posting M6MRG 73/

[@zarzosaandoni]

Hi, I want to build this same antenna but I don't have much money and In spain those type of capacitors are very hard to find. So I thought I could make one. I found some tutorials to make air gap capacitors and they seem to work great. I'm only going to use this for recieving so I don't really know if I have to use an air gap capacitor or if I can use a regular FM radio variable capacitor. Could you please confirm that? And by the way, would it be bad if the capacitor I end up making its more than 50pf? I made the calc to make it 50pf but I'm sure it will end up being more than that. Thanks for the video!

[@revoadan618]

Thanks, what value of Air Caps will i use to TX 50-75watts with 1inch tube at 13ftloop? bit so confused of the PF and Voltage value. I know theres a lot on the internet but still confused.

[@KU9L]

This looks like a good home brew project for QRP portable use, too bad the Magnum 1012 is no longer available. Dave - KU9L

[@rayday007]

Awesome video, although I made one as yours, I put mine on a Delorean, and had to replace your capacitor with a flux capacitor that was enough to handle and help generate 1.21 Jiggawatts from a bolt of lightning ⚡️

[@RadioHamGuy]

That sounds great, and the size of that rim should work out well for 20 meters!

[@namdogtag]

radiohamguy Thank you for responding....Yes, I will absolutely let you know the performance results using the MFJ 1810T 10 meter antenna when conditions get better....I also have a MFJ 1812T telescoping antenna with the bnc connector to run on 12 meters....I check the QRZ propagation report daily looking for that opportunity...I have the MFJ 259B to check these antennas out with and they are a perfect match dead center of the bands ....I also got a hamstick dipole to check out later.....73's

[@rodrigosantaliestra8246]

Thank you so much for the time to share your project. I have a sailboat and am wanting to put an SSB radio to use 20m or 30m of bandwidth. I understood how it works but I was in doubt about the power meter with the germanium diode. How would he fit into your scheme? Which direction does the diode need to be installed? On the polarity of the meter?

[@RosssRoyce]

Thanks so much!! I wonder if Large and small square shapes (for ease of construction) would work too in the transformer-type action.

[@RadioHamGuy]

@wb0zur Thanks there Denton..fun to do, lol..

[@steven123483]

The trouble with using a fixed capacitor is that these antennas have an extremely high Q. What this means is that if you are using. A fixed cap the band width will be very narrow. Very narrow. Also another issue is that you need a very high q capacitor and one with low dielectric loss Remember that the voltage at the cap is very very high. Higher than you might expect so use caution when operating this antenna.

[@NH7L]

I'm a longtime user of small magnetic loops antennas, but anyone considering using one to transmit really should first read up on loop safety issues online. Even at QRP power, they can burn you or deliver multi-hundred-volt shocks. Their near fields ... again, even at QRP power levels ... can be a danger also. On receive, as you might expect, they're entirely safe. They're the best small HF antennas around, but you really have to be careful if you transmit with one.

[@VE3RKP]

I love playing around with antennas too, Maybe adding a servo motor to the plastic shaft you could remotely tune it from outside or perhaps an attic. you could add a rotor too :-) It sure is cheaper to build your own. 73, VE3RKP

[@hevans1944]

What a wonderful video! I just bought four ten-foot lengths of 3/4" hard copper tube (used normally for plumbing), eight 45 degree "street" elbows and two 90 degree elbows to make a hex loop with 5' sides for 80 m and 40 m. Bought two 3/4" x 2' pipes, and two 1" x 2' pipes to make two series-connected bazooka tuning capacitors. I hope to be able to feed this mag-loop with my KX3 tranceiver driving a KXPA-100 final. You have given me great hope that I can actually make it work! 73 de AC8NS - Hop

[@akepatinagaraju8564]

Sir Ssb Bluener about plz