On Fri, 13 Jan 2017 18:27:54 +1100, Kevin Foster <kfoster@internode.com> wrote:>I have tried various online calculators and get inconsistent results. >Maybe because the values are too high. > >Could someone please tell me the correct way determine how many turns >are required on a coil with the following specs to obtain a resonant >frequency of 8 (eight) Hz? > >30 awg enamel coated copper wire > >Laid multi-row, multi-layer into a 1 metre diameter hoop made of 25mm >wide by 16mm deep rectangular PVC trunk conduit. > > From this I can calculate the length and weight of wire required. > >Kevin FosterDon't know about plants, may be similar as watching paint dry. But about useful coils and their self resonance I have used this site and links there. http://www.g3ynh.info/zdocs/magnetics/part_1.html And there too is more you ever wanted to know.
Calculate Resonant Frequency Large Loop Coil
Started by ●January 13, 2017
Reply by ●January 13, 20172017-01-13
Reply by ●January 13, 20172017-01-13
On Saturday, January 14, 2017 at 3:45:55 AM UTC+11, mixed nuts wrote:> On 1/13/2017 11:26 AM, John Larkin wrote: > > On Fri, 13 Jan 2017 16:19:32 +0000, Martin Brown > > <|||newspam|||@nezumi.demon.co.uk> wrote: > >> On 13/01/2017 07:27, Kevin Foster wrote: > >>> I have tried various online calculators and get inconsistent results. > >>> Maybe because the values are too high. > >>> > >>> Could someone please tell me the correct way determine how many turns > >>> are required on a coil with the following specs to obtain a resonant > >>> frequency of 8 (eight) Hz? > >> > >> In the ballpark of at least 1000x more turns than would be needed to > >> make a coil that self resonates at a much more reasonable 8MHz. > >> > >>> 30 awg enamel coated copper wire > >>> > >>> Laid multi-row, multi-layer into a 1 metre diameter hoop made of 25mm > >>> wide by 16mm deep rectangular PVC trunk conduit. > >>> > >>> From this I can calculate the length and weight of wire required. > >> > >> Several truck loads at a rough guess. > >> > >> You would be a lot better off adding an external capacitor to it. > >> Back of envelope mental arithmetic suggests for 8Hz : > >> > >> eg. > >> > >> 400uF & 1H > >> 400nF & 1kH > >> 400pF & 1MH * this might be around the self resonant regime > >> (give or take an order of magnitude either way) > > > > I suspect that the q would be so low that the resonance is > > undetectable. > > He could use superconducting wire and soak it in liquid helium. Then it > will be terrific. You won't believe how great it will be. > > I seen a picture of something like that hanging from a helicopter and > got a good close look at the G10 dewar they put it in. > > http://library.seg.org/doi/abs/10.1190/1.2035912?journalCode=gpysa7Or he could use high-temperature superconducting wire and soak it in liquid nitrogen, which is much easier to get hold of. Our Dutch friend - Jan Panteltje - was posting about doing that, shortly before he stopped posting. I used buckets of liquid nitrogen when I was doing my Ph.D. - my vacuum line depended on liquid nitrogen-cooled cold traps to condense the gunk being pumped out before it could mess up the diffusion pump, and we never had any problems. In theory, liquid nitrogen exposed to air picks up oxygen from the atmosphere, and liquid oxygen is a potent oxidant and was - in times past - used with charcoal to make an industrial explosive, so he could have managed to blow himself up. -- Bill Sloman, Sydney
Reply by ●January 14, 20172017-01-14
On Fri, 13 Jan 2017 16:19:32 +0000, Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote:>On 13/01/2017 07:27, Kevin Foster wrote: >> I have tried various online calculators and get inconsistent results. >> Maybe because the values are too high. >> >> Could someone please tell me the correct way determine how many turns >> are required on a coil with the following specs to obtain a resonant >> frequency of 8 (eight) Hz?Trying to receive Schumann resonances ??>In the ballpark of at least 1000x more turns than would be needed to >make a coil that self resonates at a much more reasonable 8MHz. > >> 30 awg enamel coated copper wire >> >> Laid multi-row, multi-layer into a 1 metre diameter hoop made of 25mm >> wide by 16mm deep rectangular PVC trunk conduit. >> >> From this I can calculate the length and weight of wire required. > >Several truck loads at a rough guess. > >You would be a lot better off adding an external capacitor to it. >Back of envelope mental arithmetic suggests for 8Hz : > >eg. > >400uF & 1H >400nF & 1kH >400pF & 1MH * this might be around the self resonant regime >(give or take an order of magnitude either way)That 400 pF stray capacitance for a multiturn multilayer coil seems quite low. I have built several loop antennas into hola hoops, some with multiconductor (flat)cables connecting each conductor in series. The self resonance may easily drop below the MF broadcast band, so you could tune it only downwards with an external variable capacitor.>I have a sense of deja vu about this thread.
Reply by ●January 14, 20172017-01-14
On 13/01/17 18:27, Kevin Foster wrote: Yes, this is an ongoing research project, and someone here had previously indicated the self-resonance of such a coil would be in the ELF range. Actually, the person who originally suggested such a configuration to me is quite experienced in this field. The loop is an alternative to a solenoid-type coil that requires a lot more wire to achieve the same effect. Unfortunately, he is no longer contactable, so I am trying to understand the process of how he arrived at the specs so I can replicate or modify it. Any help along these lines would be appreciated. Kevin Foster
Reply by ●January 14, 20172017-01-14
Kevin Foster wrote:> > > Yes, this is an ongoing research project, and someone here had > previously indicated the self-resonance of such a coil would be in the > ELF range. > > Actually, the person who originally suggested such a configuration to me > is quite experienced in this field. The loop is an alternative to a > solenoid-type coil that requires a lot more wire to achieve the same effect. > > Unfortunately, he is no longer contactable, so I am trying to understand > the process of how he arrived at the specs so I can replicate or modify it. > > Any help along these lines would be appreciated. > > >** Did the guy who advised you look like this ? http://susers.thatsmyface.com/y/yksnoy/alfred_e__neuma_front_eyegREp0S1-largeThumb_a52f19ec.jpg .... Phil
Reply by ●January 14, 20172017-01-14
On Sat, 14 Jan 2017 11:02:18 +0200, upsidedown@downunder.com wrote:>On Fri, 13 Jan 2017 16:19:32 +0000, Martin Brown ><|||newspam|||@nezumi.demon.co.uk> wrote: > >>On 13/01/2017 07:27, Kevin Foster wrote: >>> I have tried various online calculators and get inconsistent results. >>> Maybe because the values are too high. >>> >>> Could someone please tell me the correct way determine how many turns >>> are required on a coil with the following specs to obtain a resonant >>> frequency of 8 (eight) Hz? > >Trying to receive Schumann resonances ?? > >>In the ballpark of at least 1000x more turns than would be needed to >>make a coil that self resonates at a much more reasonable 8MHz. >> >>> 30 awg enamel coated copper wire >>> >>> Laid multi-row, multi-layer into a 1 metre diameter hoop made of 25mm >>> wide by 16mm deep rectangular PVC trunk conduit. >>> >>> From this I can calculate the length and weight of wire required. >> >>Several truck loads at a rough guess. >> >>You would be a lot better off adding an external capacitor to it. >>Back of envelope mental arithmetic suggests for 8Hz : >> >>eg. >> >>400uF & 1H >>400nF & 1kH >>400pF & 1MH * this might be around the self resonant regime >>(give or take an order of magnitude either way) > >That 400 pF stray capacitance for a multiturn multilayer coil seems >quite low. > >I have built several loop antennas into hola hoops, some with >multiconductor (flat)cables connecting each conductor in series. The >self resonance may easily drop below the MF broadcast band, so you >could tune it only downwards with an external variable capacitor. > >>I have a sense of deja vu about this thread.When I was a kid I made a big non-resonated loop antenna and connected it to an amp and headphones. The atmospheric noises (lightning, chirps, whistles) were really cool to listen to. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●January 14, 20172017-01-14
On 14/01/17 21:52, Phil Allison wrote:> Kevin Foster wrote: >> >> >> Yes, this is an ongoing research project, and someone here had >> previously indicated the self-resonance of such a coil would be in the >> ELF range. >> >> Actually, the person who originally suggested such a configuration to me >> is quite experienced in this field. The loop is an alternative to a >> solenoid-type coil that requires a lot more wire to achieve the same effect. >> >> Unfortunately, he is no longer contactable, so I am trying to understand >> the process of how he arrived at the specs so I can replicate or modify it. >> >> Any help along these lines would be appreciated. >> >> >> > > ** Did the guy who advised you look like this ? > > http://susers.thatsmyface.com/y/yksnoy/alfred_e__neuma_front_eyegREp0S1-largeThumb_a52f19ec.jpg > > > > > .... Phil >He was an electronics engineer specializing in geomagnetics. A very helpful and respected guy. Kevin Foster
Reply by ●January 14, 20172017-01-14
In article <58nk7c15mko6h9tshts99bbomsnpooc32c@4ax.com>, jjlarkin@highlandtechnology.com says...> >self resonance may easily drop below the MF broadcast band, so you > >could tune it only downwards with an external variable capacitor. > > > >>I have a sense of deja vu about this thread. > > When I was a kid I made a big non-resonated loop antenna and connected > it to an amp and headphones. The atmospheric noises (lightning, > chirps, whistles) were really cool to listen to. > > >Until it got too close and made it your final.
Reply by ●January 14, 20172017-01-14
In article <72ee2fa3-a210-404b-ac5b-4702f0d64105@googlegroups.com>, pallison49@gmail.com says...> > Kevin Foster wrote: > > > > > > Yes, this is an ongoing research project, and someone here had > > previously indicated the self-resonance of such a coil would be in the > > ELF range. > > > > Actually, the person who originally suggested such a configuration to me > > is quite experienced in this field. The loop is an alternative to a > > solenoid-type coil that requires a lot more wire to achieve the same effect. > > > > Unfortunately, he is no longer contactable, so I am trying to understand > > the process of how he arrived at the specs so I can replicate or modify it. > > > > Any help along these lines would be appreciated. > > > > > > > > ** Did the guy who advised you look like this ? > > http://susers.thatsmyface.com/y/yksnoy/alfred_e__neuma_front_eyegREp0S1-largeThumb_a52f19ec.jpg > > > > > .... PhilGood one! ;)
Reply by ●January 14, 20172017-01-14
On Sat, 14 Jan 2017 16:29:44 -0500, M Philbrook <jamie_ka1lpa@charter.net> wrote:>In article <58nk7c15mko6h9tshts99bbomsnpooc32c@4ax.com>, >jjlarkin@highlandtechnology.com says... >> >self resonance may easily drop below the MF broadcast band, so you >> >could tune it only downwards with an external variable capacitor. >> > >> >>I have a sense of deja vu about this thread. >> >> When I was a kid I made a big non-resonated loop antenna and connected >> it to an amp and headphones. The atmospheric noises (lightning, >> chirps, whistles) were really cool to listen to. >> >> >> > >Until it got too close and made it your final. >That wasn't nearly as dangerous as the Kerr Cell. -- John Larkin Highland Technology, Inc lunatic fringe electronics
