lightning scatter

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pe1etr
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Joined: 07 Oct 2014 00:40
Location: Blackpool UK

lightning scatter

Post by pe1etr » 19 Jul 2017 18:44

I did some experiments during a local thunderstorm.

I can't remember if I have had lightning scatter on band 2 pm FM before, I know I have had analogue UHF TV via this mode before.

Nothing exotic just Sandale, but it worked. I did have some pop music on 90.3 though along with BBC R3.

I'll hunt through my IQ files later.

I was monitoring my Sony ST-S311 live but did record a few IQ files fromm SDRplay.

Safety note
My aerials are indoors.(ring dipole and square quad loop)
How many people on here have earthed their aerial masts?

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Sylvestre
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Location: Berville-sur-Mer, France
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Re: lightning scatter

Post by Sylvestre » 19 Jul 2017 20:03

When I was young I also experimenred "storm" propagation on FM using indoor antenna and sometimes I could catch some >100Km stations...

My actual outdoor antenna is not earthed but my place has rare storms (thanks to the Seine river ?)
DX-FM & DX-TV in Normandy, France : Portenseigne 910 03 02 & Wisi EB-66 on Yaesu G450C.
On my personal website :
my DX-FM pictures, my DX-FM audios, my DX-TV pictures, and my DX-TV videos.

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pe1etr
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Location: Blackpool UK

Re: lightning scatter

Post by pe1etr » 20 Jul 2017 08:04

video here
https://youtu.be/FEH8OoOp7rQ

Thanks for your reply Sylvestre

Andrew Webster,Wigan
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Re: lightning scatter

Post by Andrew Webster,Wigan » 20 Jul 2017 10:52

Nice video Peter never had that here bands are too chocker here.

Regarding earthing masts I have not earthed mine in the 37 years it's been there but lets face it if they got a direct strike it wouldn't matter if they were earthed or not everything would be toast.
We do have some degree of protection here as the masts on Billinge hill will draw some of the charge away and all the trees as well.

I know what happens when lightning strikes a chimney I witnessed this back around 1964/5 I saw lightning hit a chimney on the gable end of a house and chimney fell off and went through a bungalow roof next door.
There was no aerials on that chimney we didn't need them around here on VHF we used indoor aerials.

Andy
Receiving equipment: 2 Sony ST-S311, 1 Sony ST-SE520, 1 Sony ST-SE700 2 crossed FM 5s rotatable, 1 homemade FM 3 horizontal beaming S/E, 1 vertical FM 3 fixed beaming at Ireland, 2 element band 1.

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pe1etr
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Re: lightning scatter

Post by pe1etr » 20 Jul 2017 11:01

Andrew Webster,Wigan wrote:
20 Jul 2017 10:52
Nice video Peter never had that here bands are too chocker here.

Regarding earthing masts I have not earthed mine in the 37 years it's been there but lets face it if they got a direct strike it wouldn't matter if they were earthed or not everything would be toast.
We do have some degree of protection here as the masts on Billinge hill will draw some of the charge away and all the trees as well.

I know what happens when lightning strikes a chimney I witnessed this back around 1964/5 I saw lightning hit a chimney on the gable end of a house and chimney fell off and went through a bungalow roof next door.
There was no aerials on that chimney we didn't need them around here on VHF we used indoor aerials.

Andy
Thanks Andy.

I have lost a 56k dial-up modem to a lightning strike, in South Africa.
I have heard a church being hit in Blackpool and a power transformer on a pole in Thailand outside a shop being hit.
I was very close to the latter. I was watching the thunderstorm from my hotel entrance next door.
Peter Blackpool

satnipper
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Re: lightning scatter

Post by satnipper » 20 Jul 2017 17:22

The biggest risk with lightning strikes is not a direct strike but a nearby strike which hits a transformer or something which causes a huge current surge. Though your master power switch may trip it's normally too late to save "delicate" items such as modems/routers/PCs etc.

Here in the Cabardes badlands of southern Occitania I track incoming storms on https://www.lightningmaps.org and unplug everything well before it arrives. I know from bitter experience what may happen if you don't.

daveB
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Re: lightning scatter

Post by daveB » 20 Jul 2017 21:01

I pull out all the aerial leads and shut down! I can't disconnect the pre-amps etc and one of then was killed a couple of weeks back. This time it looks like the youview box got zapped - couldn't get it to work even after totally re-loading software - it just wouldn't change from "waking up" - and I thought kissing it would be going a bit too far :D

The storm earlier in the week was certainly spectacular - looking towards the south the sheet lightning was almost continuous - with the added bonus of cloud to cloud forked lightning arcing across the sky from time to time. A friend of ours told us that they tried to complain to the council because the street light outside sent a huge spark to towards their house and caused problems. I explained to them they had actually seen the start of a lightning strike - which starts from the ground. A good thing the street light is a few yards away!
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

Andrew Webster,Wigan
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Re: lightning scatter

Post by Andrew Webster,Wigan » 21 Jul 2017 15:36

That's very unfortunate David loosing stuff is not good I have not lost anything to lightning here but have to the short duration powercuts off on off on in the space of a few seconds now they can be devastating I lost a PC power supply and a Sat receiver due to this the problem with this is you can't see it coming.
A TV engineer who worked for Visionhire in St Helens told me after thunderstorms they had loads of VCR's with blown RF amps but only from St Helens area and non from Billinge so means hills are not targets well not with masts on top.

I remember when I was a kid in the early 60s getting up in the early hours watching thunderstorms from my bedroom window which looked over St Helens and also power to Billinge was knocked out in thunderstorms as they didn't have the auto reclosers we have today so meant someone had to go to substation to reset the breakers.

Regarding the Youview box might be worth looking at the PSU capacitors and see if any are bulged if the box was off for a while then try warming the caps with a hairdryer and see if it comes back to life.
Faulty caps loose capacitance when cold and capacitance increases as they warm up so replacement is the cure if this is the case of course there's the possibility it is bricked.

Andy
Receiving equipment: 2 Sony ST-S311, 1 Sony ST-SE520, 1 Sony ST-SE700 2 crossed FM 5s rotatable, 1 homemade FM 3 horizontal beaming S/E, 1 vertical FM 3 fixed beaming at Ireland, 2 element band 1.

Andrew Webster,Wigan
Posts: 1907
Joined: 18 Sep 2014 16:03
Location: Wigan Northwest England
Contact:

Re: lightning scatter

Post by Andrew Webster,Wigan » 21 Jul 2017 16:20

Here are some videos about lightning from Open University back in the 80's

O U PROGRAM ABOUT LIGHTNING
Part 1
https://youtu.be/eHUk2O9qJi4

Part 2
https://youtu.be/HSv-h_xEt9c

Part 3
https://youtu.be/wN0jwGtz1OY

Andy
Receiving equipment: 2 Sony ST-S311, 1 Sony ST-SE520, 1 Sony ST-SE700 2 crossed FM 5s rotatable, 1 homemade FM 3 horizontal beaming S/E, 1 vertical FM 3 fixed beaming at Ireland, 2 element band 1.

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