My Low Cost Magnetic Loop Antenna For 10-12 Meters
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- Опубликовано: 12 дек 2011
- 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. 
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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!!
Just passed my Foundation so very new to the hobby but at some point in the future this is the type of a project I want to practice on. Thanks for posting
Wonderful video. Production quality is so great that it is a pleasure to watch. The dedicated mic really improves things. You do a great job of explaining the principles. Thanks, bill
Excellent video...Enjoyed the fact that you put your bloopers on the end...Not afraid to show ur mistakes is honorable...You have encouraged me to build my own with your simplistic explanation and walk-through...Thanks...73
thank you for being so generous .A very impressive demo- I have finally learned and understood something about loop antennas
Just picked up a realistic htx-100. Going to Lowes tomorrow. Great video.
Station from the city of São José, state of Santa Catarina (southern Brazil) very well picked up.
Great antenna. Congratulations!!!
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
'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!
Great presentation, the greatest audio ever! Thanks!
Very very cool, Love the bloopers at the end !!
Thank you for this video, and this is the best explanation I have come across for this type of antenna. 73
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
Thanks Howard and good luck with the projects! Hope things work out well for you there. 73
Will have to try a 20 meter loop antenna. Larry, you did a very good job explaining the antenna.
73's de Kilo Bravo Niner Wide Noisy Signal.
Thank you, yes, they are very easy to build and experiment with and they do work very well for the size.
this looks like just what I was wanting. looks great, thanks !
Excellent video, I'm going to try and build an 80 meter helical wound loop antenna. The signal strength demo is very impressive!
Nice vid and competently explained how to build a good quality loop antenna. Thank you.
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
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
KEØNJG.
VERY VERY NICE.
will be building as well. Grab your tools and get to work. Build it and show off.
Great fun
Congratulations!
Wonderful video. Production quality is so great that it is a pleasure to watch it!
73 de VA6POP
Vasile
Great video, I liked the Bloopers section at the end!
Thanks for the video. I used a 50uA meter I got on the internet, wish my meter was as small as yours.
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
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.
Thanks so much for the video and your time. I live in an apartment and trying to find the right antenna for HF is crazy if you don't have the space for it. I'll give the magnetic loop antenna a go and maybe find the one to fit my needs. Thanks again and 73.
Gwen - K6GRH
Thank you very mutch, mister! You'r a big help. I'll make try to make one for my Cb set.
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.
Nice I like your videos thanks for the hard work you put in
Thanks! Appreciate the comments very much. Have fun with radio...Larry
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.
Exellent presentation I just recently got into the 10 meter and was think I might try to build one of these loop antennas for my self
73's matt
Thanks and good luck with that project, sounds great!
Great video Larry and nice project. I just purchased a used 1012, and I have been rattling my brain on an antenna project for extended range. This just might be doable.
Thanks, yes , this antenna works great with my 1012, much better than even the long range rubber duck.
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
Thanks for this video. It's clear and well presented. I am in the process of making one as we speak. My configuration calls for a 22 pF tuning capacitor. Thanks again.
+Philip Gardner Thanks Philip, glad you got some use out of it and good luck with your loop, they can be a very fun antenna for the size of them!
+RadioHamGuy Hello Mr. WD0AKX, Thanks for your reply. I love your videos. They are really clear and informative. I did finished my project but is having some issues with the SWR reading. I cannot get it down below a 3. I used the calculator for the design and based on the results I made the antenna to spec. Here are my specifications. My conductor length is 8 feet soft copper tubing, Diameter of the conductor is .750 (3/4) ". The frequency intended to be used for is 27 MHz. My input wattage could be as high as 250 Watts. The tuning capacitor suggested is 22pF. I purchased the KP1-4 3-50 pF 25 Kv Military High voltage vacuum variable capacitor for this project but ended up with a 3 SWR match. Not sure what the issue really is at this point but is trying to try different things to see if it would go down but with no luck thus far. Just wanted you to know that I did go ahead with the project.
+Philip Gardner Hi Philip, sounds good on the project, just off hand I am thinking the 8ft might be slightly too large with 3-50pf cap but I don't have the calculator handy so I will have to look into that a little more otherwise you should see a nice dip in SWR when tuning the cap that goes down to 1:1. Be sure all your connections to the cap are very solid and when testing, your loop is away from other objects. Also, start with very low power, 250 watts is a very high wattage for a loop that size so you may see arching on the cap but sounds like you have a large cap rated for high voltage like that. You do not want to be close to that loop if you run more than a few watts. Very high RF levels around those loops even with low wattage so be careful experimenting.
+RadioHamGuy Hi again Mr. WD0AKX. I have to let you know that I am being careful with this antenna. I am not going to put that wattage into it at this time because I need to find the reason why my SWR is up top 3. I did go through the calculator to design it. For some reason I do think that the cap required is not the correct value. I have found another calculator and for the same dims the cap required is 12pF (+/ - 10%). Here is the link to the other calculator I used. It's www.digitalskywave.com/mag_loop.html
Thanks so much for responding. Please keep up the great work that you are doing. I love all of your videos. You are greatly appreciated sir.
That's a neat little antenna
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.
@MrSuperheterodyne Thanks! Yes, very easy to make and works quite well for the size. Very close in performance to a dipole if done correctly.
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. :)
That sounds great, thanks and good luck with your antenna project!
Instablaster
Thank you for sharing and explaining things so clearly. Enjoyed the video. Subbed.
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.
Great project to experiment with.
Good to hear, good luck, should work well for you. Thanks for the comment!..Larry
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.
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.
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
@patchcords yes, I know some people do add a servo motor to tune remotely. Great idea for mounting remotely from the shack.
Still liking this now!
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
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.
Nice schematic, in the end! I'm going to build one too ;-)
Thanks, yes, it could be one solution for you in that situation, sure worth trying it out.
very good work.I Sub ed. looking forward to many good ham video's. Thanks, Fred
Excellent presentation. Thank you. You kind of focussed on transmission, how do I tune it for reception ?
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 ⚡️
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.
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?
Thanks so much!! I wonder if Large and small square shapes (for ease of construction) would work too in the transformer-type action.
@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.
Great video, I want to build a loop for 20m QRP and your video has giving me some ideas, I'm thinking of using a bicycle rim after taking the spokes and hub off for the main loop, I'll have to get experimenting!!
@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...
where did you get the red plastic tube used to adjust the capacitor?
Great video and well made.
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
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.
That sounds great, and the size of that rim should work out well for 20 meters!
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?
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.
Just superb!
Cool loop
Hello and thanks again! What should be the length of big loop for 40m tx?
very nice and clear..good work !!
Thank you! Glad to hear that you enjoyed it.
@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
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.
Thank you very much for this nice video, i learned from it, i want to make a loop antenna for my ft-857d, thanks again and 73s! Sander Verweij, Boskoop, The Netherlands ;-) no call yet :D
If you were to put a tuning capacitor on a dipole antenna in an analogue way where should you place it and how would you connect it?
Is there a reason you flattened out the tubing for the smaller loop? Does it affect performance?
Great video! Very very inspirational. I am definitely going to have a go at making this.
Seems like a good 'poor mans' directional ant, since most of it can be made out of scrap.
Even the airspaced capacitor like you say can be found in most junkboxes, and at worst is just a £5 investment. Thanks for this, very enjoyable!! 73
@kcscarecrow sounds great, they are a lot of fun to work with and play around with..easy project.
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!
Larry I would like to know is It possible to use battery cable for a car to construct a dipole or for a magnetic loop? It's good grade copper and insulated just wondering. thank you.
very nice presentation ty
Hey nice video. Think I will build some for my yeasy 817. Really like the bloopers section, got a good laugh. Take care. Dave W4GSM
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..
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 ...
How do you measure the variable capacitor in case you want to made the antenna perminate on the frequency?
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 RUclips explaining this, but I am confused about the correct way, please help
Hi Larry thats spot on buddy i must try make one top marks
Great video!
Hi Larry, which is the pF value of the capacitor variable you use in this video? sorry i m not speak english.
What difference - if any - would making the smaller loop movable relative to the larger loop? Some way to slowly move it closer or farther away? Any effect on transmit or receive efficiency?
Hi I was wondering if you know were a guy could get a Magnum 1012 or some kind of hand held radio like this one you are using
Thanks for the nice comment and 73!
SWR??? have you ever related the peek power out with the SWR the HT sees???
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.
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?