Hello Paul , thank you for all the great work you're doing about the making and showing the assembly of the antenna, BUT I got really lost and I wished you had shown a schematic diagram of the connection of the loop to the variable cap.. just saying... thanx & regards, Luigi VK3OLA
Thank you for the tutorial and especially that you went through each band and showed how to tune and which band it tuned on. Very nice to see. This antenna was quite practical in size. Could you consider doing a follow up episode to make a second version of this to expand its band width to cover more bands and maybe see if it helps if you expand its circumference (but within the size that fits on the wall). Hope to see more of this. Thumbs up!
Nice. I add comment that only the *stator* plates of the capacitor are used. One side of the loop is connected to one set of stator plates, and the other side of the loop is connected to the other set of stator plates. The rotor plates become the connection between the two loop ends. High current thus flowing back and forth in the loop do not experience loss in the "wipers" of the variable capacitor, the wiper is not used. This is similar in function to a *butterfly capacitor* and is very efficient. It also doubles the voltage handling capacity of the capacitor. During transmit, the voltage on the capacitor can be much higher than the feedline voltage, for a low power transmitter, the capacitor will likely have a few hundred volts.
I agree with your criticism. Several minutes of confused explanation could have been replaced by a couple of sketches, where series capacitors or series capacitors would have been commented. Maybe he underestimates his audience.
buenas noches Poul gracias por el video y tu trabajo para informar , te comento que me fabrique una loop magnetica para los 40 metros con tubo de aluminio y funciona bastante bien e tenido barios contactos con otros colegas radioaficionados. Saludos de CD3FZS ...73
Please give a schemtic on how the two loops are connected to the capacitor gangs. This looks like some kind of "mobious" loop but it is extremely difficult to see and follow the connection explanation. A schematic of loop to capacitor gang stator and rotator would be a big help. Thank you.🙂
Hi Paul - love it ! Would you ever consider building one of these for another ham radio operator ? My build skills are poor but have always wanted to try mag loops !
Great project, many thanks for the very detailed explanations. One minor observation, if you have the possibility to 3dit and upload again the material: at minute 19: 50, the SWR minimum value is 1. It never goes to 0. Cheers! 73 by YO2MNE
Question. When figuring the size of the small loop ( ie 1/5 diameter of large loop ), do you use the equation of the circumference of a single loop, or the circumference X2, since the two loops are wired in series? Thanks from Jim KA9TII
Thank you very much Paul for your always interesting videos. Would it be possible for you to make us a diagram as clear as possible of the two options you indicate to connect the two coaxial loops with the capacitor? Thank you very much in advance. 73 friendly from EA2BCT
Very interesting video! I'm very surprised that you were able to run 10 watts with that very narrow gap capacitor! I would have expected it to arc even at 5 watts. The double loop design also increases the voltage seen at the capacitor when compared to a single loop. I'm wondering why you used the center conductors of the coax, rather than the shield. My understanding is that the surface area of the loop is very important and therefore, using the shield instead would improve performance. I don't think I've seen the center and shield used to extend the effective length of the loop. Have you put one together that way to test, or are you speculating?
"I would have expected it to arc even at 5 watts." As shown, the "Q" is going to be rather low. But I agree, 10 watts is really pushing it if you have a good, high-Q construction. It would also almost be impossible to tune without vernier dial.
Id like to do this in a closet, attic or lay down flat 6” off the roof. Something where you can’t see. I’ve been wanting a huge Yagi but either my height in the backyard hidden in the trees or flat against the slope of my roof Not sure what direction I should go. I always google (highest DB gain antennas) I was thinking about making my entire roof an antenna or gutter, something where it’s massive but part of the house. Need to study study study theory and stop relying on others to think for me (I’m not a ham yet).
Hey Paul. Thanks so much for sharing your information. I like loops, they seem to perform very well for me in limited space. Just wondering though. I would like to place a loop permanently high up outside my house, but was wondering....can I run the variable capacitor remotely. Example, down line in the house. Thanks so much for your vids!
The capacitor ought to be in the loop. High currents can flow in the loop and it becomes resonant with the capacitor. The capacitor end is high impedance and that means a feedline would have to be high impedance, ladder line might work. Remote tuning capacitors are usually used for this purpose. HOWEVER, it appears loop antennas do not require the height above ground compared to dipoles. Generally speaking, one loop width above ground is sufficient. It couples to the magnetic field, not the electric field (mostly) and thus does not have a mirror image in the ground (physical earth, dirt). More or less. I get very good results with a mag-loop. It makes a BIG difference how much area is encompassed; one big turn is a LOT more effective than two turns adjacent. At lower frequencies space constraints mean you might have to double the turns. Anyway, it *probably* does not require to be mounted high, just high enough to clear electric and/or magnetic shielding. Being able to rotate it would be handy to take advantage of its ability to "null" an offending signal. It mostly ignores a signal arriving axially, which is to say, directly through the center of the loop. Best reception is when the signal hits the edge first and as shown is vertically polarized and looking down from the top, would be a figure-8 lobes.
I do this ignoring the center conductor and using only the shield. You need lowest possible resistance in the loop and skin effect means the signal penetrates only a few microns. The effect of that is the center conductor at radio frequency has much higher resistance than would be measured by an ohm-meter. The shield has more surface area hence less resistance.
Hello Paul. I cant access those kinds of capacitors on my QTH. Whats the alternative or recomendation (if any)? Would you be so kind as to share link to it as well? many thanks and 73s
If you choose the four loops option, won't be importat that two of them would be shielded by the two others? Will they receive signals well? For example if we use just as reception antenna only.
Ahoj Pavol, prosím, odkiaľ berieš tie ladiace kondenzátory? Prosim, máš nejaky link na konkrétny kondik pre túto aplikáciu ktorý vydrží QRP? Ďakujem veľmi pekne! 73, de OM1AMP
Hello Paul, nice GDR-made capacitor you have here. Made in 1989, TLG aproved, a 'good' one! Very old stock, I think I still have a view of them in my drawer! Is it not 'possible' to use it for 'QRPp-TRX action' ? (sending with less than 1W?) Do you try this? Thanks a lot for an other interesting video! 73 de Markus - db9pz (JN39fq - 3miles/5km east of LX)
I don't see the point of a loop antenna. I tested one, a GOOZEEZOO MRA-821, using an Eton Elite 750 receiver but it didn't pick up as well as the radio's built in whip antenna and also gets more noise!
"I don't see the point of a loop antenna." A properly built magnetic loop antenna intercepts the magnetic field of the arriving signal, whereas a dipole or whip intercepts the electric field. At a few wavelengths from the antenna, either works fine and about the same effectiveness. But up close, the loop tends to ignore electrical interference from motors, LED and CFL lamps, things that have electrostatic interference but little or no magnetic interference. Loops are effective indoors and in apartments.
@@thomasmaughan4798 The key words here are "properly built magnetic loop antenna"! The GOOZEEZOO MRA-821 and 3 others like it that I tried are just rubbish!
You have to be able to reach the tuning knob to be able to tune it and that's one of the main drawbacks of this type of antenna so you wouldn't want to put it outside where it's out of reach or in a snow storm.
![40M UltraLight QRP magnetic loop antenna + TEST [ XIEGU X5105 ]](http://i.ytimg.com/vi/dcs5srMJamE/mqdefault.jpg)
![40M UltraLight QRP magnetic loop antenna + TEST [ XIEGU X5105 ]](/img/tr.png)
Detailed instructions on how to make metallic plate holder were very helpful 😉
Hello Paul ,
thank you for all the great work you're doing about the making and showing the assembly of the antenna, BUT I got really lost and I wished you had shown a schematic diagram of the connection of the loop to the variable cap.. just saying...
thanx & regards,
Luigi VK3OLA
Thank you for the tutorial and especially that you went through each band and showed how to tune and which band it tuned on. Very nice to see. This antenna was quite practical in size. Could you consider doing a follow up episode to make a second version of this to expand its band width to cover more bands and maybe see if it helps if you expand its circumference (but within the size that fits on the wall). Hope to see more of this. Thumbs up!
Excellent project and presentation. I have all the parts for this weekend's project. The closet door in my office will make a good rotator. John K0EBC
Nice. I add comment that only the *stator* plates of the capacitor are used. One side of the loop is connected to one set of stator plates, and the other side of the loop is connected to the other set of stator plates. The rotor plates become the connection between the two loop ends. High current thus flowing back and forth in the loop do not experience loss in the "wipers" of the variable capacitor, the wiper is not used. This is similar in function to a *butterfly capacitor* and is very efficient.
It also doubles the voltage handling capacity of the capacitor.
During transmit, the voltage on the capacitor can be much higher than the feedline voltage, for a low power transmitter, the capacitor will likely have a few hundred volts.
Paul, you are very talented. Thanks for this instructional video. I may just try and build one.
Hello, loops connections explanations are a little bit confused, and not realy clear, just a simpke schematic should be better isnt it?
I agree with your criticism. Several minutes of confused explanation could have been replaced by a couple of sketches, where series capacitors or series capacitors would have been commented. Maybe he underestimates his audience.
@@NamasenITNpub
Same here. I cannot understand how the loop is connected to the capacitor gangs.
Excelente explicación!....👏👏👏👏
Great build and work Paul. You are very talented
73
Looks interesting, but what's the difference from a two-turn loop using a single 1648mm coax? It was not clear enough how the 2nd option was built.
buenas noches Poul gracias por el video y tu trabajo para informar , te comento que me fabrique una loop magnetica para los 40 metros con tubo de aluminio y funciona bastante bien e tenido barios contactos con otros colegas radioaficionados. Saludos de CD3FZS ...73
Buenas tardes......Hola colega podrías pasarme info de tu loop?...Saludos desde 🇦🇷
Awesome stuff Paul!! 👍👍👍👍
Please give a schemtic on how the two loops are connected to the capacitor gangs. This looks like some kind of "mobious" loop but it is extremely difficult to see and follow the connection explanation. A schematic of loop to capacitor gang stator and rotator would be a big help. Thank you.🙂
Nice little antenna! Thank's for this very good video! The best from LB1NH 🙂
Looks very interesting Paul I give it ago over the weekend
Hi Paul - love it ! Would you ever consider building one of these for another ham radio operator ? My build skills are poor but have always wanted to try mag loops !
Great project, many thanks for the very detailed explanations.
One minor observation, if you have the possibility to 3dit and upload again the material: at minute 19: 50, the SWR minimum value is 1. It never goes to 0.
Cheers!
73 by YO2MNE
Thank you. I am sorry but is not possible to edit already updoaded videos, but I am sure people will understand the point 😃👍
Question. When figuring the size of the small loop ( ie 1/5 diameter of large loop ), do you use the equation of the circumference of a single loop, or the circumference X2, since the two loops are wired in series? Thanks from Jim KA9TII
Pavol Briliant!!! Thanks a Lot
Thank you very much Paul for your always interesting videos. Would it be possible for you to make us a diagram as clear as possible of the two options you indicate to connect the two coaxial loops with the capacitor? Thank you very much in advance. 73 friendly from EA2BCT
Very interesting video!
I'm very surprised that you were able to run 10 watts with that very narrow gap capacitor! I would have expected it to arc even at 5 watts. The double loop design also increases the voltage seen at the capacitor when compared to a single loop.
I'm wondering why you used the center conductors of the coax, rather than the shield. My understanding is that the surface area of the loop is very important and therefore, using the shield instead would improve performance.
I don't think I've seen the center and shield used to extend the effective length of the loop. Have you put one together that way to test, or are you speculating?
"I would have expected it to arc even at 5 watts."
As shown, the "Q" is going to be rather low. But I agree, 10 watts is really pushing it if you have a good, high-Q construction. It would also almost be impossible to tune without vernier dial.
Id like to do this in a closet, attic or lay down flat 6” off the roof. Something where you can’t see.
I’ve been wanting a huge Yagi but either my height in the backyard hidden in the trees or flat against the slope of my roof
Not sure what direction I should go. I always google (highest DB gain antennas)
I was thinking about making my entire roof an antenna or gutter, something where it’s massive but part of the house. Need to study study study theory and stop relying on others to think for me (I’m not a ham yet).
Hey Paul. Thanks so much for sharing your information. I like loops, they seem to perform very well for me in limited space. Just wondering though. I would like to place a loop permanently high up outside my house, but was wondering....can I run the variable capacitor remotely. Example, down line in the house. Thanks so much for your vids!
The capacitor ought to be in the loop. High currents can flow in the loop and it becomes resonant with the capacitor. The capacitor end is high impedance and that means a feedline would have to be high impedance, ladder line might work. Remote tuning capacitors are usually used for this purpose.
HOWEVER, it appears loop antennas do not require the height above ground compared to dipoles. Generally speaking, one loop width above ground is sufficient. It couples to the magnetic field, not the electric field (mostly) and thus does not have a mirror image in the ground (physical earth, dirt). More or less. I get very good results with a mag-loop. It makes a BIG difference how much area is encompassed; one big turn is a LOT more effective than two turns adjacent. At lower frequencies space constraints mean you might have to double the turns.
Anyway, it *probably* does not require to be mounted high, just high enough to clear electric and/or magnetic shielding. Being able to rotate it would be handy to take advantage of its ability to "null" an offending signal. It mostly ignores a signal arriving axially, which is to say, directly through the center of the loop. Best reception is when the signal hits the edge first and as shown is vertically polarized and looking down from the top, would be a figure-8 lobes.
A question - what You do with shields of main loop coax? Are they connected somewhere?
built mine and it works 40-10, no shield connection required anywhere, hope this helps
I do this ignoring the center conductor and using only the shield. You need lowest possible resistance in the loop and skin effect means the signal penetrates only a few microns. The effect of that is the center conductor at radio frequency has much higher resistance than would be measured by an ohm-meter. The shield has more surface area hence less resistance.
This models wall loops antenna will be suitable for hand held k5 quensheng ?
Great antenna
What sort of rotator do you suggest for moving the wall around?
Hmm good question 😆
Hello Paul.
I cant access those kinds of capacitors on my QTH. Whats the alternative or recomendation (if any)? Would you be so kind as to share link to it as well?
many thanks and 73s
If you choose the four loops option, won't be importat that two of them would be shielded by the two others? Will they receive signals well? For example if we use just as reception antenna only.
The shields are electrostatic, not magnetic. So, it will still work. However, a physically larger loop works much better than two small loops.
What are the measures for that antenna for 14250KHz without an extra tuning capacitor ?
Very nice video. Nice antenna. Thank you. KW4PW
Ahoj Pavol, prosím, odkiaľ berieš tie ladiace kondenzátory? Prosim, máš nejaky link na konkrétny kondik pre túto aplikáciu ktorý vydrží QRP? Ďakujem veľmi pekne! 73, de OM1AMP
Ahoj. Zdroj nezverejnujem, ale na ebay sa daju najst take tiez, ale iba v kusovych mnozstvach.
Hello Paul, will it work on 11 meter also ?
yes mine works well on 27mHz
How to make similar but for 40 20 15 10 meters for 2 wat digital ft8 trx?
Hi OM0ET, what is the voltage on this capacitor during TX?
Hello Paul, nice GDR-made capacitor you have here. Made in 1989, TLG aproved, a 'good' one!
Very old stock, I think I still have a view of them in my drawer!
Is it not 'possible' to use it for 'QRPp-TRX action' ? (sending with less than 1W?)
Do you try this?
Thanks a lot for an other interesting video!
73 de Markus - db9pz (JN39fq - 3miles/5km east of LX)
Very nice ! 73 👍
god job
I don't see the point of a loop antenna. I tested one, a GOOZEEZOO MRA-821, using an Eton Elite 750 receiver but it didn't pick up as well as the radio's built in whip antenna and also gets more noise!
"I don't see the point of a loop antenna."
A properly built magnetic loop antenna intercepts the magnetic field of the arriving signal, whereas a dipole or whip intercepts the electric field. At a few wavelengths from the antenna, either works fine and about the same effectiveness. But up close, the loop tends to ignore electrical interference from motors, LED and CFL lamps, things that have electrostatic interference but little or no magnetic interference. Loops are effective indoors and in apartments.
@@thomasmaughan4798 The key words here are "properly built magnetic loop antenna"! The GOOZEEZOO MRA-821 and 3 others like it that I tried are just rubbish!
Couldn’t you use auto tune to reach 40M?
mine tunes 10-40 easily but its 2 x 84cm loops
UNCLEAR! DO YOU MEAN THAT CONDENSER SECTIONS CAN BE CONNECTED IN PARALLEL OR SERIES???
На відео не зрозуміло під'єднання петель до конденсатора.Хотілось би побачити сематично на малюнку обидва варіанти під'єднання.
Já bych na anteně přidělal ještě jeden závit koaxu
I don't understand indoor antennas unless you live in North Korea.
The best indoor antenna will struggle against the worst outdoor antenna.
You have to be able to reach the tuning knob to be able to tune it and that's one of the main drawbacks of this type of antenna so you wouldn't want to put it outside where it's out of reach or in a snow storm.
Some people are not allowed to put up antennas outside.
@@PIasmaZombie DOH! Didn't even think of that. Sound obvious now. 🙄
DEBERÍAS HACER UN CIRCUITO DIBUJADO, NO SE DISTINGUE BIEN EN EL VIDEO.