Inaccuracy of the Stormscope with respect to distance estimate is a non issue IMHO. The later design units do a better job, but even the old Ryan 7 did what it needed to accomplish. It kept me out of thunderstorms. I have become quite adept at interpreting the radial spread and using it along with the rate of strikes being displayed to gage where it is and how intense. It is just a strategic planning tool and is not useful for tactical picking your way thru a line of thunderstorms. I also have satellite delivered lightning information based on ground sensors that are much more accurate and at the same time less useful as they are sparse and delayed several minutes. I use the Stormscope for what it was intended to be used for.
I have very good navigation equipment and Satellite NEXRAD weather, but if the Stormscope says I will have a good flight on my current path, that is what happens.
The magnetic loop antennae are used to find the direction of the strike. The outcome however is ambiguous with respect to 0/180 degrees. You then use the electric field (sense) antenna to disambiguate the 0/180 degree solutions.
At least that’s how it’s done in the ADF (and I thought all brits were experts about ADF 8-)), see this AvWeb
article.
I would expect this to be done the same way in a storm scope. So you need the E field (in addition to the H field) to get an unambiguous direction.
Low frequency it is then:
http://www.google.com/patents/US5263368
This report shows that the lightning spectrum at 100MHz is some 70dB down.
So yes, you can hear it in FM radio if the strike is close and the station weak, but you don’t need a stormscope to locate a strike hitting a few 100m away from you! You need a stormscope to locate strikes far away, where those highly attenuated parts of the waveform aren’t useful. Furthermore, the receive antenna will further attenuate these very high frequency parts.
Also, even 100MHz is well below the interesting atmospheric absorption above several GHz.
Yes, but all the interesting absorption effects start at the GHz range, while the lightning spectrum lies in the double digit kHz! So about 4 orders of magnitude in between.
You still hear lightning strikes on an FM radio – the bulk of the power may be in the KHz but not all of it. There was still a fair amount of attenuation at the FM frequencies – 100MHz or so.
Maxwell theory…I believe..
That’s what we’re talking about. Problem is, from the received signal strength, you can either work out the distance or the original signal strength at the source (lightning), but not both. So since you want the distance, you need to make assumptions about the original signal strength. And these guesses are not very reliable.
Satcomms is either expensive or unreliable or both.
And we’re having this discussion because stormscopes are cheap and reliable 
I must be doing something wrong with the thuraya phone, because so far it worked pretty well – ah yes I’m not using a Lenovo laptop from the last decade
f I remember it’s more of a distance based calculation based on the electromagnetic H and electrostatic E field computation. Maxwell theory…I believe..
Blitz used to support an API and I used to have a little prog (Lview) which gave me the image on my desktop (winXP). A few years ago that stopped, and the man said it was too much bother supporting it.
I wonder if one could transmit the short messages using some sort of “below noise floor” method, at GHz frequencies, and covering all of Europe? Satcomms is either expensive or unreliable or both.
Particularly in a damp atmosphere.
Yes, but all the interesting absorption effects start at the GHz range, while the lightning spectrum lies in the double digit kHz! So about 4 orders of magnitude in between.
Well AFAIK short (length wise) intercloud strikes can reach up to the single digit MHz, but AFAIK aviation stormscope can’t receive them.
So stormscopes measure the intesity of the arriving strike, and compare it to some “normative strike” to calculate the distance. Too bad if the actual strike didn’t comply to the “normative strike”.
My guess is that the fudge factor doesn’t come from different frequency attenuations, but they likely try to infer from the look of the time domain waveform how strong the original lightning was.
That’s why time of arrival methods like Blitzortung are vastly superior, IMO.
So I personally would (actually have) rather invest my money into a sat link to access blitzortung than to retrofit a stormscope. And that saves weight too.
