Anyone tried making a whistler receiver? They're VLF (200 - 10,000 Hz) and the idea is they catch the music of the earth. They pick up all sorts of natural disturbances like lightning, solar wind, etc. Kind of popular in the late 1900's.
Actually I recall an article in Popular Electronics from either the late 1950s or perhaps the very early 1960s for a whistler receiver project. It wasn't complex, but I do recall the antenna was a number of large loops of wire hung on a closet door. You could open or close the door to aim the antenna.
I never built that one, but I did build a very simple VLF converter. It was a simple Xtal driver thing, and whatever your Xtal freq was, your VLF showed up as a sum or difference signal either side of the fundamental on your short wave. I had some 7MHz or so Xtals, and listened to a lot of VLF traffic, mainly to use as code practice. There are some VLF broadcasts that were like UP or AP wire stories in morse code. Or there were back then, anyway.
I never built that one, but I did build a very simple VLF converter. It was a simple Xtal driver thing, and whatever your Xtal freq was, your VLF showed up as a sum or difference signal either side of the fundamental on your short wave. I had some 7MHz or so Xtals, and listened to a lot of VLF traffic, mainly to use as code practice. There are some VLF broadcasts that were like UP or AP wire stories in morse code. Or there were back then, anyway.
The Whistler was discussed in QEX a few years back, here's a link:http://www.radio-astronomy.org/pdf/qex/whistler-proof.pdf
The main thing about VLF receivers is antenna efficiency, and to get away from mains interference and fields. I used to run stuff like this for scientific purposes, some decades ago..... Antennas used to be multiturn loops with 100 sqm++ in crossection. Basically a good loop and a MC/line preamp without the RIAA should do the trick, and then a small amp to listen..... a tall tree and some multiwire cable could help in making a decent antenna
There are cheap small handheld receivers with simple whip antennas in the msrket, but I don't remember the make and name... have to check....
There are cheap small handheld receivers with simple whip antennas in the msrket, but I don't remember the make and name... have to check....
Thank you all for the input. I hadn't considered the 50/60 Hz interference factor from the mains. Easy enough to make a filter though. Probably no reason to get 1/4 mile from them.
Also surprised to hear about interference from cars driving by (static from tires) or interference from flying insects.
Very interesting articles.
Also surprised to hear about interference from cars driving by (static from tires) or interference from flying insects.
Very interesting articles.
I run a pro audio service shop. One day I had an amp on the bench, and it made a sort of buzzing sound every now and then for a short time, then it stopped. Otherwise it worked. But it regularly made this buzz for maybe 20 seconds, then it stopped for maybe 40 seconds. Cycled continuously. I could find nothing wrong with the amp, it drove me nuts. Then once while it was running, I took a break for a moment of fresh air on the front steps. I could hear it from there. Happened to catch my eye, down at the end of the block was a traffic light, and every time one color light came on in one direction, the noise resulted in my amp. So there was a noisy triac or something, in a traffic signal a block away, that was getting picked up by the amp.
One time as a young man, I was DXing on my radio late at night. That meant turning the volume up and listening hard to weak signals. Unfortunately I was also receiving loud static every now and then. Took me a while to find there was a noisy thermostat on my dad's fish tank.
While DXing on my car radio, driving down the interstate, static from truck tires as I passed them was common.
Point is, there is unexpected electrical interference all over the place.
One time as a young man, I was DXing on my radio late at night. That meant turning the volume up and listening hard to weak signals. Unfortunately I was also receiving loud static every now and then. Took me a while to find there was a noisy thermostat on my dad's fish tank.
While DXing on my car radio, driving down the interstate, static from truck tires as I passed them was common.
Point is, there is unexpected electrical interference all over the place.
Coincidentally, I was talking with a friend about this phenomenon just a few days ago. I recall a receiver project article in the '80s magazine Science Probe. I'll track down the specific issue in my files.
Cool stuff! I would not have suspected the truck tires. Tho I have had LED traffic lights cause static on FM.
A couple of years ago I was interested to find out what signals might be IN the ground. Turns out, there is a ton of 60Hz and harmonics in ground below the North American suburbs. Maybe I'll do some listening here in Hawaii.
A couple of years ago I was interested to find out what signals might be IN the ground. Turns out, there is a ton of 60Hz and harmonics in ground below the North American suburbs. Maybe I'll do some listening here in Hawaii.
I remember seeing a schematic for a superregenerative receiver for VLF that used a 6U8 and a TV horizontal oscillator slug-tuned coil. I might have the schematic written down in one of my notebooks from boyhood.
I haven't seen any mention of this particular schematic on the Net. It may have been in the of the old Golttlieb circuit compendium books that were floating around in the 60's.
I haven't seen any mention of this particular schematic on the Net. It may have been in the of the old Golttlieb circuit compendium books that were floating around in the 60's.
They put a 250KV transmission line system across the street from my house in Florida. That mess had harmonics up into the 80 meter ham band, 3.5 to 4 MHz. On a rainy or humid night the "S" meter on my Yeasu would sit at S9 making reception of all but the strongest signals impossible. Now that I am in the middle of nowhere, things should be much quieter.
Back when I was a kid, I read an article in one of the magazines about how hams that were forced off the air during WWII communicated by sending signals through the ground. I and a friend who lived a block away devised an experiment. I took my code practice oscillator and ran it through a tube amp of maybe 10 watts, and connected the speaker outputs to two pieces of rebar that had been pounded into the ground. My friend had two pieces of rebar in the ground connected to an amp feeding a pair of headphones. There amongst the 60 Hz buzz was the faint sound of my code. OK, it took 10 watts at 1KHz to travel maybe 1000 feet. A distance easily covered with a 3 transistor walkie talkie from Lafayette!
There are some SERIOUS high power VLF signals available to test your receiving equipment. We had a VLF receiver at work to pick up the standard time signal from WWVB at 60 KHz. They broadcast out of Colorado and can be heard around the world. NAA used to broadcast signals to submarines with 2 MEGAWATTS of power into an huge antenna system several miles long on 17.8 KHz. The frequency was changed to 24 KHz several years ago.
There are reports of people receiving these signals with a preamp, a 24/96 sound card and some software.
Ever wonder why school busses have chains toughing the ground from underneath? It's to discharge the static before a kid gets zapped by the bus when he touches it. Remember the zap in your car radio as you pulled up to a toll boot on a high speed road? Its that conductive plastic wiper sticking up out of the road just before you give your quarter to the attendant discharging your car so you both don't get zapped.
I haven't seen one in years, but back long ago a lot of cars had a grounding strap hanging down underneath. As I recall it looked like a huge piece of solder wick bolted to the chassis. We are talking 1950s now. My dad had explained to me it was to kill that static spark you got sliding across the car seat and stepping on the ground. remember bench seats?
I've read about such low frequencies (VLF and the even lower ELF) actually used for communication, as with submarines.
ZEVS, The russian 82 Hz ELF transmitter
http://www.oldradio.com/archives/jurassic/ELF.doc
ZEVS, The russian 82 Hz ELF transmitter
http://www.oldradio.com/archives/jurassic/ELF.doc
You can find a lot of practical information on VLF reception, as well as lots of other unusual analog circuits:
Electronics
Electronics
There are scores of guys in the US who track down the specifics of this interference -- we have it in NJ from HT lines, rail lines and traffic management systems.
It didn't take a rocket scientist to find the interference. On a hot humid summer night you could see the corona glow on the insulators. We are talking quarter of a million volts on a dusty dirt road in your back yard. They would fly by with a helicopter and spray the insulators, which would quiet the noise for a few weeks, then it would be back.
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