If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #809
Joined: Wed May 30 2007, 08:59AM
Location: Melbourne, victoria
Posts: 114
Hey guys, my friend and I have had an idea (Not new idea) of using a super high gain amplifier that would detect the EMP from the lightning strike, and amplify it enough to be useful, like flashing a LED.
I have a little USB interface board with 0-5V analog input, and I was thinking, of the strikes further away would generate less of m EMP, so lower voltage, so I could even use that to roughly estimate, or compare the distance of the strikes.
Has anyone used this simple method before, or any links, circuit diagrams you know of? I have tried google but they seem a bit over-complicated for what I am trying to do.
Registered Member #531
Joined: Sat Feb 17 2007, 10:51AM
Location: Burlington, Vermont
Posts: 125
Try This is Charles Wenzel's much copied detector.
Ranging of the strike is more complicated than simple peak detection, but the "stronger is closer" rule applies in general.
Note that you do not need a super high gain amplifier at all, there is plenty of energy to be detected. In the past, using a high impedance unity gain "active antenna", I have scoped lightning induced pulses on a short whip "antenna" that ranged into the 100s of mV and occasionally hit 1V in amplitude. This was from a storm that the weather service claimed was 500 km down the east coast from me.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
kv wrote ...
Hey guys, my friend and I have had an idea (Not new idea) of using a super high gain amplifier that would detect the EMP from the lightning strike, and amplify it enough to be useful, like flashing a LED.
I have a little USB interface board with 0-5V analog input, and I was thinking, of the strikes further away would generate less of m EMP, so lower voltage, so I could even use that to roughly estimate, or compare the distance of the strikes.
Has anyone used this simple method before, or any links, circuit diagrams you know of? I have tried google but they seem a bit over-complicated for what I am trying to do.
Range wouldn't need to be any more than 100km.
Hi there Lad!
Welcome to the world of Natural Radio! - the world of sometimes strange and erie radio signals produced by our Atmosphere - the world of tweeks, whistlers, spherics, and growlers.
First, can we brush talk of 'EMP' out the back yard? 'Electro-Magnetic Pulse' is a technical term for the interaction of our Earth's geo-magnetic field with Compton electrons knocked out the Air by high energy gamma in a nuclear strike. It is not just a little squirt of electromagnetism!
Now to take your excellent idea of a Natural Radio to pieces and show you how it can very easily be put back together in a way that will really work.
Everyone's been to see a band and heard the awful shrieking of feedback from the loudspeakers to the microphones. In fact, if you took the mike and pressed it upon against the speaker the howling would grow to such a strength it could easily burn out the whole system.
So what's this got to do with your Natural Radio Mark One? Imagine the radio signal produced by a lightning bolt as the tiniest whisper in the microphone. You amplify it one million times to play it through your speakers - and whadya get - that terrible howling! As the sound of the signal in your speaker grows, the microphone will pick up more and more of what is coming out the speaker, which will then be amplified and put out through the speakers faster and faster till we have a situation called uncontrollable oscillation.
So this is why you can't simply pick out the air with antenna, amplify it and put it through a speaker. One way or another some of the amplified signal will get back into the input, only to be amplified all over again, in a never ending loop we call "positive feedback." Your receiver will actually have become a transmitter - the founding plank of two way radio.
Friend above has directed you to Charlie Wenzel's excellent site for simple, inexpensive natural radio projects Charlie can do almost anything with a couple transistors, and is a natural teacher with a heart of gold - he regularly sends out and at his own expense - less easy to find parts for some of his circuits, and it's a shame there aren't more like him.
Good Luck with it, Lad, and do please get back to us with further questions for tips and ideas arising from your first experiments listening for whistlers and growlers.
Registered Member #531
Joined: Sat Feb 17 2007, 10:51AM
Location: Burlington, Vermont
Posts: 125
I should have posted this link also, Renato's website (and book) are a tremendous resource for the natural radio hobbyist. What you are endevoring to do falls into the category of sferics detection. This is an old term from early radio history, a shortened form of "atmospherics" or lightning generated impulsive noise.
Registered Member #1829
Joined: Sun Nov 30 2008, 01:06AM
Location: Raleigh N.C.
Posts: 74
I've often wondered if something like a Hertz detector could work here. Basically a large coil or antenna with a small (look at it under a magnifying lens) spark gap. Hertz could detect the radio from a one or two inch gap discharge from across his lab so I'd think you could detect lightning strikes from at least a few kilometers.
Registered Member #531
Joined: Sat Feb 17 2007, 10:51AM
Location: Burlington, Vermont
Posts: 125
But then you have the problem of NOT detecting the closer strikes!
An interesting factoid - Popov used a coherer as a lightning detector in the mid 1890s. Tesla, of course, did the same during his Colorado Springs period.
My personal preference would be to build "Franklin's Bells". Stunningly reckless and unsafe by modern standards but what the heck....
Registered Member #580
Joined: Mon Mar 12 2007, 03:17PM
Location: Melbourne, Australia
Posts: 410
works for me, make sure the coil is of about 30cm or so in diameter. A lightning strike will appear as a wideband noise signal. If you examine the signal you can see that 1 'strike' contains several separate bursts.
Registered Member #1223
Joined: Thu Jan 10 2008, 04:32PM
Location:
Posts: 133
Lightning stike makes highest amplitude radiowaves around 10kHz. Simple OP amp board and pretty small antenna can detect lightning strikes from 4000km range with large enough loop antenna. I have 40x40cm antenna and it detects lightning at 2000km range easily.
Registered Member #531
Joined: Sat Feb 17 2007, 10:51AM
Location: Burlington, Vermont
Posts: 125
Thanks for that link Tonskulus. I like the sound card based take on the old orthogonal loops idea. Note that adding a third channel for the vertical E field would resolve the 180 deg ambiguity he shows. I suppose that's not an issue if the plan is to compare data from two different stations as he is doing.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Making a lightning detector?
As the sound of the signal in your speaker grows, the microphone will pick up more and more of what is coming out the speaker, which will then be amplified and put out through the speakers faster and faster till we have a situation called uncontrollable oscillation.
