Audio Asylum Thread Printer
Get a view of an entire thread on one page
|For Sale Ads|
That's a bit of the rub, isn't it?
After all, quarter wave would STILL be beyond gigantic.
I've seen little spiral antennas fabricated on a PC board.
And while length is important, resistance and other measurables also come into play to match the drive from what ever is used to generate the frequency in the first place.
Too much is never enough
The best antenna is just a loop and it doesn't have to be very big. I'll attach a picture of one rather than go the thousand word bit. (the major squares are 1")
You can calculate the B field using the Biot-Savert law but the upshot is that the field strength is proportional to the area and the ampere-turns.
I played around with this several years ago and found that a smallish loop hooked to a Fn generator produced a noticible effect > 10' away. But it wasn't a good effect, more of a woozy one. So I changed the frequency slightly and the woozyness cleared up.
Now my field strength was probably considerably greater than the commercial units. The antennas of the two that were pictured on-line were garbage. The spiral one has almost no effective aperture for most of the turns, they could have stopped at the eight outer ones. The other was, to the best of my recollection a wadge of wire wadded up and stuffed in a box. Garbage basically.
My take-away from my dinking is two-fold:
1. I suspect that needed to lock my local source to the current Schumann frequency but I couldn't think of an easy way to accomplish it.
2. The local field really seemed to have an affect but depending on the frequency (at least) perhaps not always beneficial.
It's really rather an interesting affair. The engineering is easy but the target pretty important and personal so it may not be the safest thing in the world to dink with.
t a loop is directional right? So one should play with positioning. The Schumann from lessemf.com used to come with an external loop (as well as adjustable gain and frequency) and now comes with something that looks like an old telephone pickup coil.
Schumann frequency varies constantly. Time of day? Local Thunderstorm? Sunspot / Flare activity? All cause shifts in the shape / size of the Ionosphere which shifts the frequency.
Nailing it down to a SINGLE frequency would necessarily be some kind of a local average, maybe, but certainly difficult to match even hourly.
Pictured antenna appears to be 28" in diameter. This is about 88" per 'lap'. 10 winds would be about 75 FEET of wire.
Wire pictured appears no heavier than 20 or 22 ga.
Would it help to FLAT wind? bunch up as in the photo?
MAJOR SQUARES = 1" ? If i read that correctly, the antenna pictured is only about 5 1/2" in diameter and makes it MUCH easier to fabricate. The big version I speculated on above, would work hung behind a wall hanging of some sort! But should be up high enough.
Too much is never enough
You've got the right dimensions of the loop I used. It wasn't anything optimum, it was just laying around from a project I did some years ago and looked like it would be good enough for a quick test. The main thing I wanted to convey via the picture is that the current should flow about the perimeter to generate the most far-field for a given diameter.
"Schumann frequency varies constantly. Time of day? Local Thunderstorm? Sunspot / Flare activity? All cause shifts in the shape / size of the Ionosphere which shifts the frequency."
That's my understanding also. I THINK the notion of using a "Schumann generator" is to generate a stronger local field that is not as "contaminated" by various beats from the power grid and such to sooth the listener's furrowed brow. Since it is near-field it shouldn't have to be very strong to prevail.
My sense of it is that most folks dump them in the long haul apparently ultimately deciding that they are not worth the effort. Perhaps a good part of their allure is novelty.
"My sense of it is that most folks dump them in the long haul apparently ultimately deciding that they are not worth the effort. Perhaps a good part of their allure is novelty."
You must either have ESP or be the reincarnation of Carnac the Magnificent. What leads you to that bizarre conclusion? I mean other than being a card carrying tweakaphobe? Lol
"What leads you to that bizarre conclusion? (that folks quit using Schumann generators).
Jess' from reading the threads on AA when it was an active topic. Do you still use one?
R. of O.
So what frequency cleared up the wooziness? If you can remember....also, how finely can you tune the thing?
"So what frequency cleared up the wooziness?"
I don't recall exactly but it was in the direction of the nominal frequency, maybe about 1 Hz.
"how finely can you tune the thing?"
Well, I didn't know so I just tried. It's an old analog Fn Gen. with an internal counter having 1Hz resolution in the 2-20 Hz range. But it looks like you can get 0.1Hz deltas fairly well if you use an external counter. The limit is just the resolution of the single turn pot which covers a decade of frequency along with the patience of the shaky ol' knob turner. I didn't assess drift but I suspect it's OK after a warm-up.
"I don't recall exactly but it was in the direction of the nominal frequency, maybe about 1 Hz."
Can you please translate that. What I was asking was what was the frequency relative to 7.83 Hz was the one that didn't make you woozy - 7.85 or 8.10 or 7.75 or some other frequency? What frequency made you woozy, the 7.83 Hz? Just curious.
The generator was lower than the "nominal" frequency but I'm not sure just how much.
I was in the middle of something else and just did the trial for the hell of it. I was shocked as could-be that there was ANY effect and there it stands. Try it! We've already spent far more time chatting about it than I did doing it. My little "experiment" was just of the poke it and see what happens nature and it took all of maybe ten minutes to set up.
It might be interesting to try different modulations to the source both AM and FM. I bet there would be a good market for electronic doormats that make peddlers feel uncomfortable and decide NOT to ring your doorbell...
....would it work on the Jehovah's Witnesses who seem to find our country abode quite an attraction, apparently. (I didn't even know they had JWs down here in NZ; I thought they were a strictly northern hemisphere phenomenon.) ;-)
You'd prolly have to switch the drive cable polarity. Or just lay it upside down.
The "Doormat of Discouragement" (tm) has a grand future worldwide...
Both good questions.
AND, which schemeatic did you work from to get a stable =~8hz?
Making a loop as in the photo is very easy. A little shelac or epoxy and it would even be fairly mechanically stable.
Too much is never enough
Post a Followup:
Post a Message!
This post is made possible by the generous support of people like you and our sponsors: