I am anxiously awaiting part 2. My favorite part of this hobby is antenna building. I have wanted to build a mag loop antenna for a while and you have inspired me to get off my couch and do it. I also went back to some of your older videos and really enjoyed them. My father worked with the team that designed and built the Digital PDP-8. I remember the old memory cores like the one you showed in one of your videos. Subscribed and can't wait for more!
Okay, I've been holding my breath for part 2 for over 3 years now. Fortunately, I have a cardiopulmonary bypass machine hooked up to my femoral artery that allows me to do this but I am still getting tired of waiting.
So very happy to see you posting videos again; you were quite an inspiration back when I was in undergrad :-) I have an unfinished loop of similar diameter, though I opted for a single turn comprised of copper foil wrapped around 4" flexible poly drain hose, with (in theory) all the seams soldered. I really ought to get back to it, as it worked very well for reception, and now I have a 1000pF vacuum variable good for a few kV...
Howdy Jeri, K4IVE, Kevin here... Your loop looks very similar to mine, except I used 3/4 inch copper water pipe and couplings to form a giant 6.5 foot octagon. I have 50 or so photos and videos of the build, so I know exactly how much work it is to chronicle a complicated build like this. It's amazing how well the modeling of the antenna system resembled the finished product. My capacitor is a massive homebrew contraption using 3/4 inch and 1/2 inch copper pipe in a compound trombone configuration. My tuning mechanism is all hydraulic, using all plastic components and water... What a crazy project, huh? 73! de K4IVE
I've been off air for about 3 years, and you are giving me motivation to get back to it, kb1pvm here, and I say thank you. I can't wait till we cross each other on the waves
Hi Jeri, good to hear that you uploaded a new video. Thanks. And also a video useful for radio listeners and radio amateurs like me. The magnetic loop has good properties, small/tunable bandwidth etc.
Excellent work Jeri. I built my first magnetic loop in 1982. After I did and brought it to the local radio club meeting, an avalanche of loop home-brewing began. It is good to see some well-made contemporary loops.
Nice build! A person doesn't need all of that hardware high in the air and a Mag-Loop has good gain and a low noise figure. I've been building and experimenting with several different designs of them for several years and a signal can be heard while the noise from a beam or dipole masks the signal. The biggest drawback is, they have a real high Q-factor and narrow bandwidth. A variable capacitor needs to have a wide spacing on it's plates depending on the power level ran into the loop otherwise the plates will arc over. That is where a vacuum variable comes in handy. Drawback on them is that they are fragile, high-priced, can bottom out, leak off the vacuum seal and the mechanical adjustments wear out. A good gear reduction drive system needs to be added for tuning on the Mag-Loop if a few kilohertz of frequency is needed to be changed. Most of the Hams just string up a dipole since it's easier to contend with and doesn't take any knowledge and expertise working with tools and materials. A Warning to experimenters and Hams transmitting on them, a lethal voltage is present on a loop when transmitting at even a low wattage level. I built a single turn 5/8" copper tube loop using a 1,000 pf air variable capacitor. The loop was good for the 80 and 40 meter bands. The plates on the variable were not spaced far enough for any kind of wattage over 20 watts. A nice large HV butterfly capacitor with wide plate spacing would be nice. I was real impressed your project and thanks for your review!
Thanks for taking the time to show how to build this type of HF antenna. Being a condo dweller has made HF a non-starter for me, I see magnetic loop antennas for sale but more than what I want to spend. I didn't think of building my own (how I missed this concept as amateur radio is all about DIY/build/experiment). I see other youtube vids on building magnetic loops, your construction practices show how to make it look really nice along with pointers how to make it endure weather.
Wow! Glad you're doing videos again. You're a ham now, and you're doing a series on mag loops. This is the trifecta of awesome! Love the detail and video production work too. I look forward to the upcoming vids, and may tackle this in a scaled down QRP-ish in the future. Thank you, this is pretty rad!!!
Jeri, I've only just found out about your videos, you are absolutely amazing.the perfect example of what a radio ham should aspire to, I'm so happy to see so many young women in the hobby, thanks Scott 2E0 IOJ
Outstanding video. I'm starting to think I live at the North Pole or something, I've never seen your channel before. Excellent build and looking forward to the next one. 73 Julian oh8stn
I built a Magnetic Loop back in 2004. It was awesome. It worked great on 40m. I have the parts to make another one with a Vac. Variable and a motor drive. It's my winter project. I have a 50 foot vertical but honestly, I want the best power and match. I also like how selective the loop is. I work Qrp and love weak signal. Thanks for the video ! I am also watching and brushing up on my electronic basics. It has been fun watching your channel. cheers.
Jeri, love your videos. One thing though I want to point out ( @ 3:26 in the video) is that Hams don't "broadcast", we "transmit". Broadcast is generally accepted as a one way transmission where there is no expected reply like in AM or FM radio stations that broadcast their signals. Hams are almost always looking for a reply or communication with another Ham thus we transmit to each other.
One exception I found where a low 160m dipole works well is for greyline into Western Australia and New Zealand from the UK when the refracting layers are steeply inclined roughly perpendicular to the path. All that high-angle radiation is a benefit, but only in that one case. Back in the 1990s, I built a 16 foot diameter magloop for 160m from 2 inch aluminium tube, TIG welded at the joints, but I used a big ceramic-cased vacuum capacitor and I think that was a mistake because of the contact losses. If I did it again, I'd fabricate a parallel-plate air-spaced capacitor, with all welded joints, and use the mechanical flex of the loop with an insulated ballscrew actuator for tuning, but I'd also use much larger tube. I'm lucky to have a couple of acres of land for big antennas, but I've always been fascinated by tiny ones. I've worked the east coast US from my 160m mobile, running 100 watts of SSB. These days I'm more into LF and microwave/mmWave but I'll always have a soft spot for Top Band
Hi, A slight improvement in the signal can be noted by pointing the "holes" of the loop to the generating source. The plane of the nulls of this antenna are parallel to the construction of the larger circle. You can use this feature to improve more good signal and attenuate noise source. Part of the noise can reach the tank tuned circuit by the coax cables through the common mode currents. A simple BALUN 1:1 installed before the smaller coupling loop can also greatly reduce noise. The balun must be BAlanced UNbalanced ... with turns ratio in 1: 1. Only producing the lag between the unbalanced antenna and the balanced coaxial line. 73 DE PU2SRZ
I think there needs to be more enforcement of shielding and drives to move back to the idea of fiber optic implementations and less wireless that isn't so well managed. Seems can create more jobs also that aren't so dangerous for enforcement operations. I suppose the JFK pervs next generation has taken hold and deviated systems to cause more jamming (not just Hollywood's), static, noise and interference. I'm sure there is more than one root cause.
The noise is lower for me using various loops than any other antenna. I usually have built full wave loops, some vertical, some horizontal. I have a decently sized piece of property. Could easily fit a 160 full wave loop. Dipoles have always been very noisy for me.
Great to see you posting again. Thought we had lost you permanantly to the big time corporate world. Sorry C-AR didn't work out as hoped, but truly happy to see you making videos again. Doc
Cool - nice build! I've got just enough room for a 80m dipole, but not nearly high enough for DX. I'll be really interested to see what kind of Q (bandwidth) you get, especially on 160m. I'm liking it so far! 73 de Alan W2AEW
The Q was interesting because it changed radically with the coupling method I used. Using a gamma match was fairly high Q on both bands. I plan on exploring if I can get the 1/5th diameter loop and ferrite coupling method to behave better.
Hmm - that is interesting. I wouldn't have expected the coupling method to have that much of an effect. I hope you explore this in future videos - great job (and proud to have you among the ham community) 73 de W2AEW - Technical Coordinator for the NNJ Section of ARRL.
Great build. I can't wait for part 2 !! Please talk as much as possible about the math behind your design. I am currently working on loop made with 4" copper ribbon - hopefully maximizing surface effect but we shall see.
I've actually had pretty good luck with the 1/5-sized coupling loop, getting bandwidths similar to those predicted by, e.g., AA5TB's spreadsheet which can be found on-line. But, that calculator and my loops are all single-turn, and I'm not sure what the double-loop design does to the bandwidth. Good luck and 73, K7HKR.
This is fantastic. Just walked through a motorcycle shop in Rochester, NY--you know, the old "cool" style shop with only old classic bikes--anyway, what did I find on the floor in the frame section? A tubing roller exactly like the one Jeri shows us in this video. Owner grants use with his blessing! I am in old-man heaven! Thanks Jeri!
Very good instructions! The white cutting boards made of polyethylene(milk jug plastic) are a good cheap source of insulation material. And it takes threads well.
Hi Jeri, I just built a Mag Loop antenna using 4 inch aluminum dryer vent tubing as the main loop and copper gas tubing as the sense with a roughly up to 300 pf capacitor that was a tuning capacitor thus double ganged. Once, I increased the sense loop's circumfrance to 6 feet or roughly 0.375 times the 16 foot in circumfrance square created by the vent tubing it began to have an impedance that allowed for about a 1.3 swr in the 40, & 30 meter bands. I was hoping for 20 meters too, but no go. I am thinking that if I use a smaller capacitor I can get it to work well on 20 meters. Yep, the tuned interval is very narrow. I had built likely 5 of these style antennas before, but they were all receive only thus I was pleased that by trial and error plus a found hint that a loop size that offered a good impedance was found. I'd like a 160 and 80 meter antenna, but it seemed the circumfrance needed for this was likely to be very expensive if I used dryer vent tubing. As it was the dryer tubing came in at $80 by itself. Nice video, kc2wvb
Whilst I understand why Jeri has constructed her loop with the tuning capacitor at the bottom of the antenna, be aware that the greatest loss in the system is Ground Loss. Placing the high impedance portion of the antenna very close to the ground will reduce the antenna’s efficiency markedly and possibly affect the Q. Also, placing the antenna in any orientation too close to the ground will have a deleterious effect on efficiency. (A quote from the late Leigh Turner VK5KLT) “The major contributor here being the steep variation in the ground loss resistance due to the very close-in induction field sensitivity. The Rgnd component falls quite rapidly with increasing height; whereas the Rrad radiation resistance changes quite benignly (image-plane reinforcement reduction), and the intrinsic antenna structure Rloss remains virtually constant with changes in height.” The answer here is to invert the antenna and get the bottom of it as far away from the ground as practical, thus reducing the ground losses. Steve Adler VK5SFA
I was unsubscribed from the channel because I assumed it was a abandoned. Now I'm glad to see your channel is alive again. Very excited to see your new videos. Bye the way your video regarding the bulb for feedback resistor in the oscillator is one of my favorite electronic/science videos. That video made me to rethink how I approached the design and funny thing I'm not even an engineer or technician . I'm an artist.... Thanks again
Awesome! Looking forward to the next video. I once made an octagonal 21ft perimeter mag loop, but making a spiral is a great idea. Thanks. What's the efficiency on either bands?
Hi Jeri, I build a second 160 meter magnetic loop antenna. I improved the match and using new feed line. I use Kenwood TS-50s, Yaesu FT-897D and Drake SPR4 for receiving. Big improvement on 160 meter receive. Also I home brew 1296 and 10 GHz for EME Moonbounce . Thanks Jeri. 73 Andrew WB4BKC .
Dearest Jeri Ellsworth: Love your stuff, and want to build this antenna-but I'd like YOUR advice/dissent on sourcing a variable capacitor (I'd rather not fail often and buy the wrong parts over and over (fail often) as my time and funds are somewhat limited and I have to fish too). You speak of them, but not _about them_ it in this video. Hope you are well and we get to see a PART 2 sometime soon. I'd like to build, test and tweak before Winter of 2018. You make really great videos. Thanks so much, 73.
I knew this was going to be as much fun as race car frames, and then the hole saw comes out. Just like the race car! As I was sitting here listening to skip from Michigan land in Boston. Rock on Jeri.
Hi Jeri, I have enjoyed your in depth videos in the past and am happy to see you are posing once more. Your knowledge and subject expertise is very broad and informative. Please keep up the good work and know that it is appreciate by many. Regards, Don
carabela125 Is this figure based upon the assumption that 90 extra megawatts is the difference between mere time travel (1.21GW a la Doc Brown) and an intergalactic wormhole?
Ok now there is hope for me to use 80 and 160 m as I have a very small back yard. I will be waiting for video number 2 to see how well it works and if I can use your design. Thanks so much for giving me a new prospect for the 2 bands I like.
Hey! Great to see you making videos again Jeri. I never cared much for radio but with was my Dad's obsession so ultimately it is how I got started in electronics.
I've recently been talking to guys at our radio club about getting onto 160mtrs so this project looks great it would fit nicely into my rather small back garden, I'm sure others in our club will be interested to see your project aswell.... 73, G7MNP
Have no idea what brought me here, maybe it's the building cool stuff you tube algorithm in effect, as this was/is cool to see. Can't wait to see the rest of this series.
Awesome build! Some time ago I found a 1 inch rigid copper coax cable on a junkyard nearby and used it to experiment as magnetic loop. I never finished the project, but it had promising initial results.
Great stuff.....My Granddad as a boy showed me how they used this Loop for AM radio in the war to pickup distant stations placing the radio inside the loop a right angles with a tuning Cap hooked up to about 40 turns of .5mm copper wire about 300mm diameter or how ever big your radio is to fit inside.... Cheers Brett
Fantastic Quality Video! And now we know why verticals are so popular on the low bands - take off angle. Looking forward to the full loop saga. Mike WU2D
I just bought 35 feet of 5/8" copper pipe to make a 40m mag loop antenna (single loop). It's for dedicated use for a solar powered QRP JS8 message server so it'll be tuned once with a parallel combination of 3KV fixed capacitors.
Great video. Here in the UK a lot of us use plastic kitchen chopping boards as insulators and easy to cut to shape. They are cheap and available in many thicknesses. I cannot comment on continual exposure to UV however. I am Looking forward to the next video 73 Robert De M0RCX
Very nice work Jeri. I am a huge fan of the magnetic loop, I have built 4, and I am just getting started. The simulation work you did is really informative for people just getting into this special type of antenna.
I made a 5 ft with 1/2" soft copper about 5 ft off the ground, I bought a 13" Cardwell 9 to 10 kv air variable, on Ebay, however, very touchy compared to a vacuum variable, that's next on buy purchase plan. So far there is nothing out there close to this size that performs as well on 80, 60, 40, and 30 meters, also made a 3 ft 20 through 10 meter 1/2" soldered octagon loop using a Russian surplus vacuum variable, put a scrapped printer motor as kind of a stepper with a 3 watt potentiometer as a voltage divider to control speed with a double pole double throw three position switch to change direction, have worked all over in challenging propagation conditions, and very good at cutting down the noise.
So...you're a QRPer! It's fun if you enjoy designing and building your own antenna systems. A lot of times, achievable distances can be highly atmospheric conditions dependent, but still, when you get that 1,000 mile shot at .25 watts....it's kind of awesome. Then again, there's also a rather satisfying feeling of having 70kw of RMS RF at your fingertips especially when you've designed and built it all yourself too. =)
Would be GREAT to establish a series of this type of illustrative videos as part of a concerted, collaborative Elmer/mentor program... LOTS to consider!!
Good to see more videos from you. Looking forward to the rest of this series.
I am anxiously awaiting part 2. My favorite part of this hobby is antenna building. I have wanted to build a mag loop antenna for a while and you have inspired me to get off my couch and do it. I also went back to some of your older videos and really enjoyed them. My father worked with the team that designed and built the Digital PDP-8. I remember the old memory cores like the one you showed in one of your videos. Subscribed and can't wait for more!
I’ve been waiting years for part 2. I guess if it hasn’t happened by now it’s not going to?
A new Jeri Ellsworth video. Life is good.
Okay, I've been holding my breath for part 2 for over 3 years now. Fortunately, I have a cardiopulmonary bypass machine hooked up to my femoral artery that allows me to do this but I am still getting tired of waiting.
Bummer .... Oh dear just got interested in this kind of antenna and as I also have a background in racing cars I were hoping she would lead the way..
@@kristhompson8112 Try M0MSN's channel. Mike is building a lot of Mag Loops.
What about joining forces and research the next steps ourselves? She will be happy to have inspired others.
Me too .... but nothing found
Bummer, won’t bother watching or giving it a like or follow
So very happy to see you posting videos again; you were quite an inspiration back when I was in undergrad :-) I have an unfinished loop of similar diameter, though I opted for a single turn comprised of copper foil wrapped around 4" flexible poly drain hose, with (in theory) all the seams soldered. I really ought to get back to it, as it worked very well for reception, and now I have a 1000pF vacuum variable good for a few kV...
For those curious: the larger diameter of the conductor should lead to improved bandwidth.
zinckensteel
So 3/4 inch tubing will give better bw than 1/2 inch?
Yes, but that small of a change might not be noticeable in practice.
Howdy Jeri, K4IVE, Kevin here... Your loop looks very similar to mine, except I used 3/4 inch copper water pipe and couplings to form a giant 6.5 foot octagon. I have 50 or so photos and videos of the build, so I know exactly how much work it is to chronicle a complicated build like this. It's amazing how well the modeling of the antenna system resembled the finished product. My capacitor is a massive homebrew contraption using 3/4 inch and 1/2 inch copper pipe in a compound trombone configuration. My tuning mechanism is all hydraulic, using all plastic components and water... What a crazy project, huh? 73! de K4IVE
That's awesome!
Finally she's back !!!!!! Missed your video's Jeri.
I've been off air for about 3 years, and you are giving me motivation to get back to it, kb1pvm here, and I say thank you. I can't wait till we cross each other on the waves
Let's do it!
Waiting for next "Magnetic Loop Antenna -Part 2".......WAITING! WAITING! WAITING! WAITING!
ME TOO AND HALF THE HAM GLOBE
I've been sat on the edge of my seat for a year waiting for part two. Hopefully I will not be too old to enjoy it.
Hummm been awhile,,she's working on better stuff now lol
@@m1cxf dont stop breathing lol
Me too! Did the studio cancel the series?
Welcome back!
Hi Jeri, good to hear that you uploaded a new video. Thanks. And also a video useful for radio listeners and radio amateurs like me. The magnetic loop has good properties, small/tunable bandwidth etc.
Excellent work Jeri. I built my first magnetic loop in 1982. After I did and brought it to the local radio club meeting, an avalanche of loop home-brewing began. It is good to see some well-made contemporary loops.
This and Applied Science are my two favorite channels! In a perfect world you’d have done a collaboration by now :).
We're both in Silicon Valley now. :)
i love ben!!!
Nice build! A person doesn't need all of that hardware high in the air and a Mag-Loop has good gain and a low noise
figure. I've been building and experimenting with several different designs of them for several years and a signal
can be heard while the noise from a beam or dipole masks the signal. The biggest drawback is, they have a real
high Q-factor and narrow bandwidth. A variable capacitor needs to have a wide spacing on it's plates depending on
the power level ran into the loop otherwise the plates will arc over. That is where a vacuum variable comes in handy.
Drawback on them is that they are fragile, high-priced, can bottom out, leak off the vacuum seal and the mechanical
adjustments wear out. A good gear reduction drive system needs to be added for tuning on the Mag-Loop if a few
kilohertz of frequency is needed to be changed. Most of the Hams just string up a dipole since it's easier to contend
with and doesn't take any knowledge and expertise working with tools and materials.
A Warning to experimenters and Hams transmitting on them, a lethal voltage is present on a loop when transmitting
at even a low wattage level. I built a single turn 5/8" copper tube loop using a 1,000 pf air variable capacitor. The loop
was good for the 80 and 40 meter bands. The plates on the variable were not spaced far enough for any kind of
wattage over 20 watts. A nice large HV butterfly capacitor with wide plate spacing would be nice. I was real impressed
your project and thanks for your review!
Awesome! Looking forward to the next part!
GadgetUK164 - Retro Gaming Repairs & Mods
Clearly we have the same great taste in channels.
It's getting tough to not see you on here. lol
+ElectronAsh LOL! Yep! Another great channel that we both watch lol
Looking forward to the rest of the series. How's it coming along ? KG5KYM.
A
That's quite the spiffy intro Jeri! Thanks for sharing your projects with us in such an enjoyable and educational form!
So glad to see you back :)
I'm really excited to see this series and more videos from Jeri! Thanks for the upload.
this was so cool!
Thanks for taking the time to show how to build this type of HF antenna. Being a condo dweller has made HF a non-starter for me, I see magnetic loop antennas for sale but more than what I want to spend. I didn't think of building my own (how I missed this concept as amateur radio is all about DIY/build/experiment). I see other youtube vids on building magnetic loops, your construction practices show how to make it look really nice along with pointers how to make it endure weather.
Wow! Glad you're doing videos again. You're a ham now, and you're doing a series on mag loops. This is the trifecta of awesome! Love the detail and video production work too. I look forward to the upcoming vids, and may tackle this in a scaled down QRP-ish in the future. Thank you, this is pretty rad!!!
Jeri, I've only just found out about your videos, you are absolutely amazing.the perfect example of what a radio ham should aspire to, I'm so happy to see so many young women in the hobby, thanks Scott 2E0 IOJ
Jeri, it was great to meet you at Pacificon. Looking forward to the following videos.
Someday we'll have more than 30 seconds to chat.
I'm just a tech class, but I've been searching for something this thorough (and yet concise) for a while! Thank you!
Outstanding video.
I'm starting to think I live at the North Pole or something, I've never seen your channel before.
Excellent build and looking forward to the next one.
73
Julian oh8stn
I built a Magnetic Loop back in 2004. It was awesome. It worked great on 40m. I have the parts to make another one with a Vac. Variable and a motor drive. It's my winter project. I have a 50 foot vertical but honestly, I want the best power and match. I also like how selective the loop is. I work Qrp and love weak signal. Thanks for the video ! I am also watching and brushing up on my electronic basics. It has been fun watching your channel. cheers.
Jeri, love your videos. One thing though I want to point out ( @ 3:26 in the video) is that Hams don't "broadcast", we "transmit". Broadcast is generally accepted as a one way transmission where there is no expected reply like in AM or FM radio stations that broadcast their signals. Hams are almost always looking for a reply or communication with another Ham thus we transmit to each other.
10-4 Good buddy... Sorry I couldn't resist poking a little.
LOL, I do the same thing= cb vernacular, your response made me bust out with a chuckle
You're one of my all-time heroes and finding you back on TH-cam made my day!
I can't find part 2
One exception I found where a low 160m dipole works well is for greyline into Western Australia and New Zealand from the UK when the refracting layers are steeply inclined roughly perpendicular to the path. All that high-angle radiation is a benefit, but only in that one case. Back in the 1990s, I built a 16 foot diameter magloop for 160m from 2 inch aluminium tube, TIG welded at the joints, but I used a big ceramic-cased vacuum capacitor and I think that was a mistake because of the contact losses. If I did it again, I'd fabricate a parallel-plate air-spaced capacitor, with all welded joints, and use the mechanical flex of the loop with an insulated ballscrew actuator for tuning, but I'd also use much larger tube. I'm lucky to have a couple of acres of land for big antennas, but I've always been fascinated by tiny ones. I've worked the east coast US from my 160m mobile, running 100 watts of SSB. These days I'm more into LF and microwave/mmWave but I'll always have a soft spot for Top Band
HI Jeri. Very nice work! How is the "noise" at your location? I'm located at a very high point as well.
Noise on 160m is fairly bad on the dipole, but the high Q of the mag loop helps a lot.
It's pretty high here as well, even with underground power lines. Lots of noisy consumer electronics. It's good to see you making video's again... 73
Hi,
A slight improvement in the signal can be noted by pointing the "holes" of the loop to the generating source.
The plane of the nulls of this antenna are parallel to the construction of the larger circle. You can use this feature to improve more good signal and attenuate noise source.
Part of the noise can reach the tank tuned circuit by the coax cables through the common mode currents.
A simple BALUN 1:1 installed before the smaller coupling loop can also greatly reduce noise.
The balun must be BAlanced UNbalanced ... with turns ratio in 1: 1. Only producing the lag between the unbalanced antenna and the balanced coaxial line.
73 DE PU2SRZ
I think there needs to be more enforcement of shielding and drives to move back to the idea of fiber optic implementations and less wireless that isn't so well managed. Seems can create more jobs also that aren't so dangerous for enforcement operations. I suppose the JFK pervs next generation has taken hold and deviated systems to cause more jamming (not just Hollywood's), static, noise and interference. I'm sure there is more than one root cause.
The noise is lower for me using various loops than any other antenna. I usually have built full wave loops, some vertical, some horizontal. I have a decently sized piece of property. Could easily fit a 160 full wave loop. Dipoles have always been very noisy for me.
Great to see you posting again. Thought we had lost you permanantly to the big time corporate world. Sorry C-AR didn't work out as hoped, but truly happy to see you making videos again. Doc
Nah. I was just napping.
YOU’RE BACK!
Welcome back !
Love your teaching method and enthusiasm.
Cool - nice build! I've got just enough room for a 80m dipole, but not nearly high enough for DX. I'll be really interested to see what kind of Q (bandwidth) you get, especially on 160m. I'm liking it so far! 73 de Alan W2AEW
The Q was interesting because it changed radically with the coupling method I used. Using a gamma match was fairly high Q on both bands. I plan on exploring if I can get the 1/5th diameter loop and ferrite coupling method to behave better.
Hmm - that is interesting. I wouldn't have expected the coupling method to have that much of an effect. I hope you explore this in future videos - great job (and proud to have you among the ham community) 73 de W2AEW - Technical Coordinator for the NNJ Section of ARRL.
Great build. I can't wait for part 2 !! Please talk as much as possible about the math behind your design. I am currently working on loop made with 4" copper ribbon - hopefully maximizing surface effect but we shall see.
Absolutely. I had a lot of compromises around loop diameter and matching that surprised me.
I've actually had pretty good luck with the 1/5-sized coupling loop, getting bandwidths similar to those predicted by, e.g., AA5TB's spreadsheet which can be found on-line. But, that calculator and my loops are all single-turn, and I'm not sure what the double-loop design does to the bandwidth. Good luck and 73, K7HKR.
Extremely well shot and narrated.
Incredible amount of info without droning on, i like, will keep an eye out for P2
Jeri.. where are the other parts to this video.? I want to make one too.. :)
this video pops back in my suggestions ALL THE TIME and I still have not seen part 2 after 2 years...
It's Jeri!
This is fantastic. Just walked through a motorcycle shop in Rochester, NY--you know, the old "cool" style shop with only old classic bikes--anyway, what did I find on the floor in the frame section? A tubing roller exactly like the one Jeri shows us in this video. Owner grants use with his blessing! I am in old-man heaven! Thanks Jeri!
Watching her is like watching The Return of the Jedi the long waited leader who finally returned
:D
Nice project, glad to see you back Jeri!
Newsflash: we love you!
You can contact with Poland now. :)
Siana Gearz I
Very good instructions! The white cutting boards made of polyethylene(milk jug plastic) are a good cheap source of insulation material. And it takes threads well.
Did part two get lost in the ether?
Hi Jeri,
I just built a Mag Loop antenna using 4 inch aluminum dryer vent tubing as the main loop and copper gas tubing as the sense with a roughly up to 300 pf capacitor that was a tuning capacitor thus double ganged.
Once, I increased the sense loop's circumfrance to 6 feet or roughly 0.375 times the 16 foot in circumfrance square created by the vent tubing it began to have an impedance that allowed for about a 1.3 swr in the 40, & 30 meter bands. I was hoping for 20 meters too, but no go. I am thinking that if I use a smaller capacitor I can get it to work well on 20 meters.
Yep, the tuned interval is very narrow. I had built likely 5 of these style antennas before, but they were all receive only thus I was pleased that by trial and error plus a found hint that a loop size that offered a good impedance was found.
I'd like a 160 and 80 meter antenna, but it seemed the circumfrance needed for this was likely to be very expensive if I used dryer vent tubing. As it was the dryer tubing came in at $80 by itself.
Nice video,
kc2wvb
Are you working on part 2
Travis
K5HTB
Whilst I understand why Jeri has constructed her loop with the tuning capacitor at the bottom of the antenna, be aware that the greatest loss in the system is Ground Loss. Placing the high impedance portion of the antenna very close to the ground will reduce the antenna’s efficiency markedly and possibly affect the Q. Also, placing the antenna in any orientation too close to the ground will have a deleterious effect on efficiency. (A quote from the late Leigh Turner VK5KLT) “The major contributor here being the steep variation in the ground loss resistance due to the very close-in induction field sensitivity. The Rgnd component falls quite rapidly with increasing height; whereas the Rrad radiation resistance changes quite benignly (image-plane reinforcement reduction), and the intrinsic antenna structure Rloss remains virtually constant with changes in height.” The answer here is to invert the antenna and get the bottom of it as far away from the ground as practical, thus reducing the ground losses.
Steve Adler VK5SFA
Ha Jeri , thanks for this build but when are we gonna get part II !
Best regards Carl.
I was unsubscribed from the channel because I assumed it was a abandoned. Now I'm glad to see your channel is alive again. Very excited to see your new videos. Bye the way your video regarding the bulb for feedback resistor in the oscillator is one of my favorite electronic/science videos. That video made me to rethink how I approached the design and funny thing I'm not even an engineer or technician . I'm an artist.... Thanks again
Awesome! Looking forward to the next video. I once made an octagonal 21ft perimeter mag loop, but making a spiral is a great idea. Thanks. What's the efficiency on either bands?
Impressive. The use of tools or the view from the back yard. Not sure what I like most.
Hello Jeri, which tool are you using for the radiation pattern simulations?
EZNEC which is easier than most, but not super easy.
@@jeriellsworth even better is "4nec2" which can interface with ITSHFBC to produce signal strength prediction maps
Hi Jeri, I build a second 160 meter magnetic loop antenna. I improved the match and using new feed line. I use Kenwood TS-50s, Yaesu FT-897D and Drake SPR4 for receiving. Big improvement on 160 meter receive. Also I home brew 1296 and 10 GHz for EME Moonbounce . Thanks Jeri. 73 Andrew WB4BKC .
Great video. When will the Part 2 video be available?
I was wondering myself
Glad to see you back and what an awesome project. Will be following and building with great interest. Thx!
Jeri is back :)
Totally cool build so far in this video. Must watch all of this series. Thanks.
Dearest Jeri Ellsworth: Love your stuff, and want to build this antenna-but I'd like YOUR advice/dissent on sourcing a variable capacitor (I'd rather not fail often and buy the wrong parts over and over (fail often) as my time and funds are somewhat limited and I have to fish too). You speak of them, but not _about them_ it in this video. Hope you are well and we get to see a PART 2 sometime soon. I'd like to build, test and tweak before Winter of 2018. You make really great videos. Thanks so much, 73.
I've seen loops like that before, but I never guessed they were antennas. Learned something new again. :-)
Hi Jeri when will we see the next episode of your loop antenna make
I knew this was going to be as much fun as race car frames, and then the hole saw comes out. Just like the race car! As I was sitting here listening to skip from Michigan land in Boston. Rock on Jeri.
she back
Hi Jeri,
I have enjoyed your in depth videos in the past and am happy to see you are posing once more. Your knowledge and subject expertise is very broad and informative. Please keep up the good work and know that it is appreciate by many. Regards, Don
fantastic tutorial
Please, Jeri, do not stop making videaos for us! All The Best!
Looking for 'build a 160/80 meter magnetic loop antenna - part 2'
Same here :)
It's GOOD to see you making videos again!!! I'm ALWAYS at my Happiest when I'm MAKING Gizmos!!!
If I apply 1.3 gigawatts of power will that open a wormhole into another universe? Just kidding, welcome back !
carabela125 Is this figure based upon the assumption that 90 extra megawatts is the difference between mere time travel (1.21GW a la Doc Brown) and an intergalactic wormhole?
Nice project ! It might be a good idea to cut slots in plastic hangers for avoiding water bridges under rainy conditions.
Thanks for the suggesting. Very good point.
6 months and still nothing. You are a tease.
Ok now there is hope for me to use 80 and 160 m as I have a very small back yard. I will be waiting for video number 2 to see how well it works and if I can use your design. Thanks so much for giving me a new prospect for the 2 bands I like.
OMG, she's a HAM now!
... and according to the FCC site she has an "amateur extra" license - that's the
Premium Unleaded Gasoline of amateur licenses.
Good job Jeri! Looking forward to the rest!
Wow! I've missed you and I would still marry you xxx
Hey! Great to see you making videos again Jeri. I never cared much for radio but with was my Dad's obsession so ultimately it is how I got started in electronics.
I've recently been talking to guys at our radio club about getting onto 160mtrs so this project looks great it would fit nicely into my rather small back garden, I'm sure others in our club will be interested to see your project aswell....
73, G7MNP
Right ON Jeri! Nice to meet you at SEA-PAC. Can not wait for part #2
WELLCOME BACK!!! GLAD TO SEE YOU! STILL LOOK GREAT!!!!!!!
Have no idea what brought me here, maybe it's the building cool stuff you tube algorithm in effect, as this was/is cool to see. Can't wait to see the rest of this series.
Great to have you back.
Hi Jeri, Doug Kovach here. I'm glad to see you're once again back! Been missing your shenanigans!
Nice to see something new from you! I really like your approach to explaining your projects.
Awesome build! Some time ago I found a 1 inch rigid copper coax cable on a junkyard nearby and used it to experiment as magnetic loop. I never finished the project, but it had promising initial results.
Great stuff.....My Granddad as a boy showed me how they used this Loop for AM radio in the war to pickup
distant stations placing the radio inside the loop a right angles with a tuning Cap hooked up to about 40 turns of .5mm copper wire about 300mm diameter or how ever big your radio is to fit inside.... Cheers Brett
that was some grandpa indeed
Very good editing and clear information, look forward to part two.
Great job, this is definitely something I need to build. I have the same issue with my 160m dipole. I can only get a few hundred miles
You are the most awesome chick that ever lived. I pray one of my daughters ends up being half of what you are.
Fantastic Quality Video! And now we know why verticals are so popular on the low bands - take off angle. Looking forward to the full loop saga. Mike WU2D
As long as you do not crash alien spaceships with that antenna. J/K! I look forward to seeing more of your projects! Keep it going!
Nice project. Looking forward to next in series as inspiration to build mag loop for my own limited space back yard.
I just bought 35 feet of 5/8" copper pipe to make a 40m mag loop antenna (single loop). It's for dedicated use for a solar powered QRP JS8 message server so it'll be tuned once with a parallel combination of 3KV fixed capacitors.
Jeri, good to see you back. Looking forward to more in this series.
So glad to see you back Jeri!!!
This is EPIC!!!!!! I love the mysterious mad scientist look of these antennas.
Great video. Here in the UK a lot of us use plastic kitchen chopping boards as insulators and easy to cut to shape. They are cheap and available in many thicknesses. I cannot comment on continual exposure to UV however.
I am
Looking forward to the next video
73
Robert
De M0RCX
Very nice work Jeri. I am a huge fan of the magnetic loop, I have built 4, and I am just getting started. The simulation work you did is really informative for people just getting into this special type of antenna.
I made a 5 ft with 1/2" soft copper about 5 ft off the ground, I bought a 13" Cardwell 9 to 10 kv air variable, on Ebay, however, very touchy compared to a vacuum variable, that's next on buy purchase plan. So far there is nothing out there close to this size that performs as well on 80, 60, 40, and 30 meters, also made a 3 ft 20 through 10 meter 1/2" soldered octagon loop using a Russian surplus vacuum variable, put a scrapped printer motor as kind of a stepper with a 3 watt potentiometer as a voltage divider to control speed with a double pole double throw three position switch to change direction, have worked all over in challenging propagation conditions, and very good at cutting down the noise.
So...you're a QRPer! It's fun if you enjoy designing and building your own antenna systems. A lot of times, achievable distances can be highly atmospheric conditions dependent, but still, when you get that 1,000 mile shot at .25 watts....it's kind of awesome. Then again, there's also a rather satisfying feeling of having 70kw of RMS RF at your fingertips especially when you've designed and built it all yourself too. =)
Would be GREAT to establish a series of this type of illustrative videos as part of a concerted, collaborative Elmer/mentor program... LOTS to consider!!