Lightning Scatter Propagation

[NN2E]

Bored? No E-skip? No tropo? Need something to do? Why not try Lightning Scatter?

What you'll need...

A good UHF antenna with a rotator.

A receiver capable of tuning the upper UHF channels (frequencies) in SSB or CW mode.

Another receiver to monitor for lightning events. (an analog TV, tuned to channel 2, or a broadcast band radio, tuned to an open frequency, will work)

A cluster of thunderstorms about 150 to 200 miles from you.

A fairly high powered, upper UHF channel, DTV (or, if you're lucky, analog) station, 300 to 500 miles from you, in the same direction as the thunderstorms.

Here's what I've been doing...

As I type, I have the antennas aimed at KGAN 51/2 Cedar Rapids, IA. (420 mi) through a cluster of storms in eastern MO. Using the Icom R-7000 receiver, in SSB mode, I'm tuned to the DTV channel 51 pilot carrier frequency of 692.31. I also have the analog TV parked on channel 2 so I can watch the picture jump when lightning events occur. Via normal tropo scatter, I can hear a very weak carrier on the Icom receiver. During lightning events (as monitored with the analog TV) I hear a rapid, fluttery, enhancement of the DTV pilot signal. I've moved the antennas towards KPXE 51/50 Kansas City (365mi) and I'm getting similar results. (it's a large line of thunderstorms)

A few weeks ago I did this with the antennas aimed through a cluster of storms in eastern TN. During the lightning events I could hear a chorus of channel 51 DTV pilot signals.

Back in the days when there were plenty of high-powered UHF analog transmitters I'd actually get bursts of picture by using the Lightning Scatter mode. WGBO channel 66 near Chicago (350 mi) was my favorite Lightning Scatter, "guinea pig." I've tried this same Chicago path using WPWR 51/50 as the signal source and the Zenith DTT-901 DTV box as a receiver. I've seen the signal, "meter," on the DTT-901, jump to 1/3 scale during lightning events but have yet to get a decode out of it. I'll keep trying, though.

Why the upper UHF channels? I've had the best luck with them over the years.

Will this work with FM? Yes, so I've been told. (I don't pay any attention to FM)

There's no shortage of thunderstorms this time of year so why not have some fun with them. Try it and see what happens. Share your results.

73, Ed NN2E
Owner / Operator - Murphy's Law Test Site & Thunderstorm Proving Grounds

[egrabow]

Florida gets more than its share of T-storms so I might be able to try this. Unfortunately 50 and 51 both have due-north locals. I could always focus on 46-49.

Does SSB/CW help you tell the pilot carriers apart? I've only heard them as an unremarkable hiss in AM mode.

[NN2E]

Yes. It's rare that two stations will end up on the exact same frequency so there are almost always slight variations in their DTV pilot frequencies.

73, Ed NN2E
Owner / Operator - Murphy's Law Test Site & Thunderstorm Proving Grounds

[egrabow]

I found two targets I could try for: WTVY-36 in Dothan, AL and WSAV-39 in Savannah, GA. They're each omnidirectional 100kw stations about 375 miles from here. Unfortunately, southern Georgia doesn't offer much on my open channels. But I'll be happy to try next time they're T-storms over Orlando. (Preferably without them also being here. Florida, y'know.)

[NN2E]

Had more Ls propagation this morning...

Aimed the antennas southeast, through a squall line, and again, had a chorus of signals on 692.31 (DTV ch 51 pilot carrier) during lightning events.

73, Ed NN2E
Owner / Operator - Murphy's Law Test Site & Thunderstorm Proving Grounds

[NN2E]

It's thunderstorm season, again (for the next three months we'll have a good idea of what it was like to live in London during the second world war) so, now's a good time to experiment with Lightning Scatter.

This link...

http://wiki.radioreference.com/index...on_Frequencies

...should get you to a TV frequency chart.

Pick a good DTV pilot frequency, aim your antennas through a thunderstorm and see what you can find.

Last night, I was using the channel 20 DTV pilot frequency (506.31) and getting some results by aiming through a cluster of storms in the southeastern U.S.

73, Ed NN2E
Owner / Operator - Murphy's Law Test Site & Thunderstorm Proving Grounds

[amfmtvdtvbrla]

hi Ed, thanks for posting about Lightning Scatter Propagation again. I am going to try this Lightning Scatter experiment on XEFB-59 in Monterrey Mexico in the hope of receiving there signal before it is shut down. mp11, Danny and Pat may have better luck than me of receiving their signal. Ed, does the line of thunderstorms need to be ahead in front of the receiving station or do the line of storms need to be behind the receiving station?

[NN2E]

amfm,etc...

You'll want the thunderstorms to be at the mid-point between you and the station you're trying to receive.

As I type, I'm aimed through a cluster of storms in the middle of Missouri hoping one of the Kansas City stations might chime in.

73, Ed NN2E
Owner / Operator - Murphy's Law Test Site & Thunderstorm Proving Grounds

[NN2E]

Aiming north this morning, through a line of storms, more or less in central IL..

I'm hearing a chorus of ch 51 DTV pilot signals (692.31) in parallel with lightning events.

Occasionally, one of the signals will really jump up in strength. I suspect it's WPWR Gary / Chicago at 350 mi.

On the DTV box ch 51 shows a few, very brief, flashes of signal to 1/3 scale but that's not enough for a decode.

73, Ed NN2E
Owner / Operator - Murphy's Law Test Site & Thunderstorm Proving Grounds

[Guest]

Hello Ed and the group members.

I joined after looking around for others that are interested in just this mode, as rare as it is to most. So far I have only done some preliminary observations for the upcoming spring storms that will be more prevalent then than now that we in the US are in the fall season.

I have been trying to select currently the best UHF channel(s) pilot carriers to use that does not have such high levels of aircraft reflections. Living in the Midwestern states, there is a considerable number of overflights occurring from both east and west coasts that makes it the main concern right now which UHF emitter to select that is at a low enough signal level to show lightning enhancements and minimum high signal level aircraft reflection returns.

While using a UHF log periodic antenna and antenna mounted LNA currently, has produced a considerable number of TV station pilot carriers that appear to be usable for this project, so the list is very long of which one(s) to use is not a real problem except for the aircraft reflection issue. So far, several usable DTV UHF pilot carriers are located at less than or greater than 500km confirmed by their aircraft reflections and physical locations by using https://planefinder.net/

After a decision is finally made regarding the best one to use, it is planned to build a specific frequency Yagi antenna to sharpen the antenna pattern and likely add additional gain in the process.

Looking forward to next spring !

Denny - K0LGI -

[Guest]

After posting my comments primarily about UHF lightning enhanced propagation now - about
1 year ago, I note there has been little comments or apparent interest in it by the lack of replies or comments from others.

Are there any members still investigating this admittantly unusual and rare propagation mode now ?

Now having successfully received several lightning enhanced propagated signals from UHF DTV pilot carriers observed at my Midwest location when the time and conditions permit, including some that have been recorded, is why I ask.


Thanks !

Denny - K0LGI -

[Rrrrzzzz419]

Perhaps posting the recordings here would help draw interest?