Trying to understand the lightning signals
#1
Hello Group I'm new to the group, my Name is Bill and I live in Yuba City, CA, USA. I have always had a big interest in storms and lightning and have made several detectors, just simple pulse detectors with a beeper and flashing LED. Well I have had it on the back burner to build a detector that would give me azimuth too. I was on the web page from Holland I thing for the Lightning Radar LR detector. Well I noticed it was no longer being used due the the passing of the guy who developed it, rest his sole. 

Sense I had the parts I made a PCB and put it together and Have been playing with it trying to learn from it. To my surprise I can pick up lightning a lot father away than I thought I could. From California I can see storms from the east coast of the US. My setup is  a pair of opamps and 2 fairrite loop antennas both about 200mm long. I have the antennas shielded they are connect to the opamp board in a water tight box right next to the antennas and I have cat 5 cable running to the ham shack right below it. Antennas are running NS and EW and both are tuned to 10 khz. 

OK here is where my question comes in. right now I'm connected to a digital Oscope and I set the trigger high enough so only a lightning pulse sweeps it. But I noticed that most of the time one trace is out of phase with the other one 180 degrees. I took care to make sure both antennas are connected the same ie ground and signal. Is this normal that the NS and EW signals would be out of phase 108 degrees or do I need to swap the leads on one antenna? 

I plan on connecting it to my sound card and play with it on Spectrum Lab but want to make sure it is connected right to begin with. Every once in awhile I get a signal that looks to be in phase. I hope to soon to setup the system used here using TOA, but for now I want to learn as much as I can and maybe write some software to use this setup as a portable system I can use while RVing. 

Thanks and I hope this post is OK here on this Forum, if not delete and let me know, I want to stay in good terms with the group. Also Have been watching the Biltzortung real time maps and I have to say Wow! what a great system.
Bill Verstelle
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#2
Hi Bill...
Yes, if two loops are phased correctly, and at right angles, and both signals can be viewed at the same time, it is possible, theoretically, to get at least a 'rough' azimuth by comparing the signals... Yes, there will be 'signal phase' differences between each loop, depending upon direction the signal cuts the loops.  This is NOT true for a single E field Probe, which is omnidirectional.
Some time ago, Richo, one of the developers, loaded a diagram on this forum, which I modified for my own use, Rolleyes which illustrates this.... attached.... this is basically a 'DF" (direction finding) technique, as opposed to a 'locating' technique.

Thus the Noise Signal in the third image would be sourced generally SW, assuming the antennas were NS/EW oriented... 
Note that Blitzortung does not care about azimuth.  The signals are actually 'same polarized' automatically by our processing servers, and the Time of Arrival of the discharge impulse and the computed Time of Group arrival of associated impulses is calculated against other station signals to produce a location for the sferic. This is a 'network' system, and no station stands alone. 

Cheers!
Mike


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Stations: 689, 791, 1439
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#3
Hi,  and welcome to the group.
Everything related to lightning and lightning detection are welcome
The setup you are using is designed for long range bearing.
Your antennas can easily be used to our system, but WITHOUT tuning
Depending on the direction, the phase is shifted - therefore one can detect direction.
We use the Time Of Arrival (TOA) and uses a much wider frequency range, typically 3-30 (100) KHz. We do this to get a more accurate representation of the lightning discharge.
In your experiment, you can remove the capacitor of the antenna coil, and put a resistance of 2-3 KOhm instead. You get a weaker signal, but a more correct.
If your oscilloscope can be connected as X-Y scop, you can also try it with an antenna on each channel.
Stations: 584, 585, 2017
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#4
(2016-01-30, 09:38)Cutty Wrote: Hi Bill...
Yes, if two loops are phased correctly, and at right angles, and both signals can be viewed at the same time, it is possible, theoretically, to get at least a 'rough' azimuth by comparing the signals... Yes, there will be 'signal phase' differences between each loop, depending upon direction the signal cuts the loops.  This is NOT true for a single E field Probe, which is omnidirectional.
Some time ago, Richo, one of the developers, loaded a diagram on this forum, which I modified for my own use, Rolleyes which illustrates this.... attached.... this is basically a 'DF" (direction finding) technique, as opposed to a 'locating' technique.

Thus the Noise Signal in the third image would be sourced generally SW, assuming the antennas were NS/EW oriented... 
Note that Blitzortung does not care about azimuth.  The signals are actually 'same polarized' automatically by our processing servers, and the Time of Arrival of the discharge impulse and the computed Time of Group arrival of associated impulses is calculated against other station signals to produce a location for the sferic. This is a 'network' system, and no station stands alone. 

Cheers!
Mike

Thank you Mike this is some great info and nice to know. I do realize that Blitzortung is a TOA system and I hope to have one of their systems up and running here in the future. But this setup is good to play with and learn from. 
Again Mike thank you for the post,
Bill
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#5
(2016-01-30, 10:01)RichoAnd Wrote: Hi,  and welcome to the group.
Everything related to lightning and lightning detection are welcome
The setup you are using is designed for long range bearing.
Your antennas can easily be used to our system, but WITHOUT tuning
Depending on the direction, the phase is shifted - therefore one can detect direction.
We use the Time Of Arrival (TOA) and uses a much wider frequency range, typically 3-30 (100) KHz. We do this to get a more accurate representation of the lightning discharge.
In your experiment, you can remove the capacitor of the antenna coil, and put a resistance of 2-3 KOhm instead. You get a weaker signal, but a more correct.
If your oscilloscope can be connected as X-Y scop, you can also try it with an antenna on each channel.

Thanks Richo great information and it gives me something to try and experiment with. I do have a Scope that does XY, my lovely Wife bought me a 4 channel Rigol for Christmas and I'm having a lot of fun learning it, so much better than my analog scopes. 

I have been reading about your systems, from green, red to blue and have to say what a great progression. Very well designed and the real time lightning maps are now my goto maps, they work so well. 

Thank you and others who have put in so much time to make a system that works so well in is so polished, can't wait to get involved in setting up a station here myself. 
Chears,
Bill
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#6
Welcome to the Blitzortung forum Bill.

As you poke around this website there is another one you might want to look at and join. It is an anything-weather related forum (and a lot more...) that also has a Blitzortung section. See the following link to get to the WXFORUM.NET There are quite a few hams on the WXFORUM to so you might want to use your call-sign as your username like you have here.

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