What a beautiful Setup. My Antenna Wire is the same Lenght 42,45m (42m and 45cm) and in most Cases I run a 2:1 Balun but also having a 4:1 in my portable Tool Bag for the Case of the Case. Good Job Almir, I can see you had a lot of DX Fun with this Antenna. 73 de Uncle Günter from across the Pond 💯🙋♂
@@DK5ONV Thank you Gunter! Since this was my first setup I cut it the wire a little too short so I added another meter is at 43m now I like to he more a the beginning of the band. Have a great week my friend looking forward to our first QSO. Best 73's uncle Gunter!
Thanks for sharing, nice spot for radio. Loops are great ants, especially vertical Loops. I only use resonant verticals now, but my old ant was a 40m half grounded loop, which was amazing. 73 zl3xdj.
Find me on the QRZ. Callsign KK6SPM. I used Stepper Motor HAT + Raspberry Pi. I can share the source code. If you use a 200-step motor you will need at least a 1:8 reducer.
VE3DAL, Thanks for the demo of your new Loop. Just wondering where you found the variable capacitor?... Never mind, I found it on an earlier posting.. Cheers!
I've made more than a few MLAs, but none looked nearly as nice as what you have here. I've probably made less than 10 contacts (no dx) with any of them in total. All qsos were ft8/4, except for one cw and that got me a 22 sig report. Still it is a lot of fun to build and learn from building an MLA. Mine is currently stashed behind a cabinet. I used 1/2 inch Heliax for the main loop and have experimented with many different feed coils. Hopefully I will come across a vacuum tube capacitor someday and I will give it another try. Thanks for sharing your experience.
@@user-hb5vp8jd9v Thank you so much I appreciate! My MLA in the city the results were terrible I did a few QSOs on ft8 one ssb and no dx. At the cottage was a lot better I did a quite few QSOs on ft8 dx as far as Alaska and eastern Europe. I really enjoyed to build them much more than operate them and is not my every day antenna for sure. Best 73's my friend!
Brilliant video and you are a very clever person. I just ordered the qdx for qrp ft8 80-20m, so I really do hope to hear you one day. I find ferrite clamps work as well as a 1 to 1 balun, but easier to connect. 73 zl3xdj
@@brianfields4479 Thank you so much I appreciate ! I used the 1:1 because is easier for me with that 3d clamp that I printed. Good luck with your new qrp antenna hope to hear you as well. 73's my friend
Good job Almir. Now you got a little Flamethrower to make your Signal skipping across the Pond. I can't await to finally make the 1st Contact with you on the Bands. Have a good new Week & 73 de Uncle Günter 💯🙏🙋♂
@@DK5ONV Hey Gunter ! Yes me too, this magloop is no that easy but sometimes magic happens with this antenna. Have a great week my friend and nice to see you doing well. Best 73's
A loop of 1 meter is about optimum for the 20 through 10 meter bands you are operating at this time. For lower frequencies such as 80m the loop would need to be a wider diameter. One thing to avoid when designing loops is to choose a diameter that avoids lumped current constants, which occurs typically when the loop diameter is too large for the frequency used. It's a fine balance. Larger is not always better when it comes to MLA's. Great work. I love your project.
@@danielzdanowicz6899 Thank you for the great feedback! It seems that I can't get to the 10m , my capacitance starts at 22pF with this system. Since this is my first MLA I will build some others for sure. Thanks again best 73's.
That loop should tune the low end of ten meters. You may need to reduce the capacitance to get higher in frequency. Possibly switch in a door knob capacitor in series. Also vary the coupling with the exciter loop moving it up or down the shaft a bit. If you smith chart it on a Nano VNA it should tell you what direction your experiment should go. One thing that might be worth trying too using a Delran plastic coupling between your gear works and the capacitor shaft which would further assure there is no coupling leakage at that end of the capacitor. Just some thoughts from afar. 73s
@@danimac3953 I will check that door knob capacitor for sure. I was thinking at first to reduce the size of the main loop and compromise the 20m and that would be ok because I'm thinking to build another one. There are so much into this antenna and that's what I like. Thank you so much for the tips. 73's my friend
@@VE3DAL reducing the size of the loop would definitely accommodate getting higher on ten but would compromise performance on 40 which might force a decision to be made as which end of the spectrum is more important in the scheme of things. One thing to keep in mind surface area is critical to loop efficiency. Do not use a thinner radiation loop. What you are learning from these experiments will make you the local authority on MLAs. Great work!
@@danimac3953 to tell you the truth I never try 40m on this antenna I only took a SWR reading because I knew the efficiency wasn't there due to the size. I have a quite a few feet of KMR400 coax cable to spare, where I'm thinking to do some sort of 8 figure loop to get that 40m back again. I took a quick look at door knob capacitor but I'm not to familiar how would that work comparing to the variable capacitor where you control the capacitance. I appreciate your knowledge.
Thank you for this video--great documentation of the mag-loop. Really considering going down this rabbit hole--you're reigniting my curiosity in antenna. Keep on with the awesome work (with all you videos)!!
I have quite a lot of experience with magnetic loops. You can see the two loops I have in regular service on my QRZ page. MFJ made a loop tuning box that was rated for 100+ watts. I have used one to make portable field antennas on many occasions with excellent results. It must be kept in mind that high voltages can develop across the capacitor. It is essential that you insulate the cap from the tuning knob or tuning motor particularly if you are tuning under power even a few watts. Ohmic resistances are a critical source of efficiency loss. You might do better by soldering a copper washer to the copper tubing. Alternatively, just using a screw with a large head and the smallest possible hole to connect the capacitor might be helpful. you can purchase a venier drive used to help with the small increments that tuning requires. It is generally recommended that you use a BUTTERFLY capacitor or a vacuum variable capacitor. Otherwise you will suffer ohmic losses at the wiper contacts. The effects of a very small angular change on the peak frequency is remarkable. With air variables you wiould have to use a reversible DC motor with gear reduction or even a stepper motor with gear reducion for romote tuning. My vaccum variable loop tunes remotely using a homebrew PWM motor control and a NanoVNA. Magnetic loops are surprisingly sensitive to ambient conditions; temperature changes and/or humidity changes will shift the position of the peak.
@@larrypicard5969 Thank you so much for the excellent feedback. I'm very new on MLA and any information is very helpful. My next goal is to figure out to make tuning remotely. I have a very small 12V motor with reduction gears with a controller forward and reverse that I used for my timelapse photography on rails, I'm thinking to give a shot with that. The gears that will be touching the capacitor I will make on my 3d printer. Also I will figure out how to do a better connection on the components by soldering. I will check your QRZ page. Best 73's my friend!
Nice project antenna. You may want to consider putting a 1:1 balun line insulation in the feed line coax at the antenna. MLAs are prone to common mode currents which will limit the amount of power you can apply to the antenna and limit the ability to get a good low swr. MLAs have very low radiation resistance so there can be 15 amps on the loop say at 30 watts plus thousands of volts on the capacitor. Soldering the loop to the capacitor will greatly improve efficiency and reduce mechanical resistance losses which is the biggest problem in loop design. I really like your project antenna. Great job and well engineered! Best 73s. Dan K1YPB - On the air since 1962
@@danimac3953 Hello Dani, thank you so much for your feedback! This was my first MLA , my skills on electronics are very limited and I have a lot of questions. You answer on of them that soldering the components are better than tie them with bolts and nuts. I been getting very good SWR 1:1 but I think the efficiency of this antenna is maybe 50% or less. I have some better ideas as the project still going. At the feed point I have some ferrite beads on the coax I'm not sure if helps. Wow you have been operating for a very long time that's awesome! Best 73's my friend!
@@VE3DAL Thanks for the reply. Your efforts are commendable for the first attempt. You are doing the right things. The diameter of a meter is about optimum for 40 through 10. Any longer and you would start getting lumped constants of rf current which should be avoided. A loop like yours with soldered connections and minimized mechanical IR losses can be up to 88% efficient on 20 meters even with as much as a 1.5:1 SWR. With 50% efficiency I might suspect higher than normal mechanical losses. This would usually result in "heat loss" due to the high currents normally flowing through the loop components. This can be tested quickly with extended key down time and say 35 to 40 watts, while watching the SWR meter slowing creeping up as the elements heat up. With the size of your variable cap, I would suspect it could easily handle 25 watts digital, 45 watts cw and 75 watts of SSB, and maybe even 90 watts of SSB with a balun in the feed line. However at those power levels the voltage on the cap would be in the thousands and many amps of RF on the loop. Needless to say... never contact any component of the loop under power, as the RF burns would be extremely severe. Even at 5 watts it will render a "bite" that you will not forget for a long time. RF exposure is also a concern with these types of antennae, so it is recommended to stay perpendicular to the loop plane, where the deepest null (approximately 20dB) is for safety. IF the loop is hard to tune, or the SWR changes when you touch or get near the feed line coax, and / or changes with rotating the loop you would most like have common mode currents (CCMCs) on the coax and should use the balun I mentioned earlier. The MLA magnetic "H" field is effective for a distance of about three or so loop diameters from the loop making it less bothered by surrounding (unless those surroundings are metallic), after which it starts performing like a regular antenna "E" field there out to its destination. If the "H" field is vertical, the "E" field will be horizontal. Being a Mag Loop everything is backwards from an ordinary antenna. Such as... ordinary short antennas are capacitive and need a coil to load (ie a short coil loaded vertical such as a Buddistick) where as... a small MLA is inductive and needs a capacitor to load it to resonance. The vertical mounted MLA sends out a vertical "H" field, but then dissipates and the horizontal "E" field takes over giving the small vertical ground mounted loop the equality of performance of a dipole "at height". In some cases the MLA will actually out perform a dipole, which makes the MLA a big favorite for portable ops. The MLA some times gets a bad rap from the grouchy old timers out there because they don't understand anything other than a dipole and are not willing to explore the technology of this type antenna. (Some OTs will never change... hi hi) If you can put up with the high Q of a MLA, it can be your best antenna solution for many circumstances, such as stealth ops in an antenna restrictive HOA or POTA ops where trees are limited or don't accommodate an EFHW wire. I have personally worked 7800 miles on an Alexloop one loop diameter above the ground with 10 watts on FT8... Not bad in my book. Best of luck on your continued experimentation. Have fun! 73s, Dan K1YPB
@@danielzdanowicz6899 Hey Dan, thank you so much for the info very helpful! I love to explore new technology and the challenges that comes with it, and MLA is one of them. This afternoon I changed the capacitor to be on top and the coupling at the bottom and I didn't noticed much of difference. I'm aware of the danger from this antenna, but is always great to know even more information about it. Thank you again I loved your comment. Best 73's my friend!
Great information. I was thinking about a monoband loop antenna for 20m CW portion. Would it work with smaller capacitor or a RG213 as a capcitor? Is there a way to find how much capaticance is needed?
@@geirha75 Thanks for the feedback! I very new on magloop antennas, yes it does work with a smaller capacitor it will be limited on output power. I'm still try to learn what band needs how much capacitance.
The vageries of magnetic loop antennas take a lot of learning . They are very effective in conditions where normal antennas struggle due to noise and poor propogation and the directionality of their gain means that you can pull signals out where none seem to be. I love mine ,especially for QRP , and have had some very surprising results . Keep at it - you will learn to love it as you get to know it better. (I now adjust mine instantly entirely by ear !). It's a bit like learning a musical instrument. 73 M7BLC
@@johnnorth9355 Hi John, thank you for your feedback. For me definitely still a mystery everything about it, and that's what I liked. It will keep me going for future modifications. My next goal is to test at the cottage can't wait for that! Best 73's my friend.
Nice MagLoop Almir, good Job on that. The capacitor should be on top and the small loop on the bottom. This reduces the receiver noise.Or Am I mistaken? Happy Weekend & 73 de Uncle Günter from across the Pond 💯🙋♂
@@DK5ONV Hey Gunter! Absolutely I will try that because one thing I was getting a lot of noise as it is. At first I thought it was my neighborhood. My next goal is to take to the park but this type of antenna some logistics good sense has to happen. I hope you are doing better and good luck my friend 73! Gunter buddy
Thats a great receiver antenna! I can hear another signal coming through while you were talking to someone, amazing! I can hardly wait till i set my loop up.
@@VE3DALyou could see if you can receive 2 meter signals and not transmit for now. Listen on FM and ssb if possible. I used to do a lot of 2 meter ssb. I could reach out to max 400 miles.
So Ive been reading 15 ft low point for the 40 meter loop. So I was thinking 7.5 ft for the 20 meter loop. I read too high increases the lobes and weakens the main lobe. What do you think,Almir?
I think this way of thinking it works better if you have a free environment around, if you don't like myself at home it will pickup a lot noise level like s5 s7 where I'm.
@@VE3DALThe good thing at the lake you can turn the loop! I was going to ask you did you have trouble with the tripod falling over without guy wire. I could see if you a peg or something in the ground under the tripod?
Almir, I plan to put up a vertical plane 20 meter Delta loop antenna fed with 450 ohm window line. I know you used a 4:1 balun. I was thinking maybe I should use a 9:1 balun with the 450 window line? What do you think? Also I want vertical polarization. The horizontal will be on top V configuration.
Like I said I never worked with window line yet and I heard that the window line can't have any type of metal close by to work properly, that would be an issue for me. I'm also planning to put a 20m delta loop where I have the 10m loop instead.
Nice project and place to be Almir! By the way,try next time monoband Hexagon loop! Less complicated, less sensitive about height, better SWR, more quiet and VERY effective. It only takes 15min to set up for mobile / portable use. Stay well & 73, S51X
Thank you so much ! I actually tried already and I agree is much easier sometimes with the multiple bands setup you end up using one or maybe two bands. Best 73's my friend.
I forgot to ask you how long was your wire for 20 meter Delta loop antenna at the cottage? I was going to try 1005-5% then add a couple of inches. I will have the feed point at .25 wavelength . also I'm using 450 ohm window line,4:1 balun. My hardest chore is finding 45 degree pvc elbows!😮😅
My is at about 68 feet and I have to adjust every once a while. I never used a window line yet maybe in the future. I'm sure you can find the pipes online, good luck.
You may be right. Before I had this loop just about 6 feet above ground and the SWR was flat. Now at this high the SWR is not that great. I will check his article, Thank you.
The direction is front and back but also works with some side radiation as well. Sometime ago I deploy horizontal using some trees at the cottage and worked even better than vertical. I will try that again when ever I have a chance. Let me know how the 450ohm line works for you. 73's my friend.
Hello, I used a small 4 inches zip ties to secure the wire all around the fishing rod including the tips. The wire is 18 gauge and pvc sched 40. Thank you 73's.
I elevated the feed point about 18 feet with a mfj mast and the other two corners of the triangle at the same height with some help of trees that gave me the horizontal polarization.
When your swr is high, it comes back inside. 2 ferrite beads are almost useless. You need about 10. At 15 ft up the swr shouldn’t read 9:1. The 10m wire is too short. Closer to the ground should read longer due to ground. I would re measure again
Hi Jay, I didn't have more beads and I will add more. After this first test I noticed that I have to re measure the wires. Hopefully I will get better results next time. Thank you for the comment. 73 my friend!
Hi Almir Enjoyed your video. I do have Mini Hex covering from 6m to 15m bands. Made lots of contacts. But not tried 6m. Presently in USA on vacation. Once back will again be on hex. Take care SAM VU2USA
Hi Sam, thank you so much I appreciate! I love the hex with the convenience of multiple bands. I will keep developing this project and add more bands in the future. Best 73's my friend!
