Do closed Remis blinds make a PVC into a Faraday cage?

[BrianS]

Well, according to Ken from the YouTube channel "Life is too short" it does! Go into 8 minutes on this video -


Anyone know if he is right? Is the material they are made from not a sort of paper?

 

[Richard n Ann]

The blind foil isn't grounded though so probably doesn't block the signal much.

 

[cyberyacht]

Never liked being on a yacht with a great lightning conductor sticking up in a thunderstorm

Yeah, creepy ain't it.

 

[Albacore]

But is that still the case when a vehicle is on rubber tyres?

I wondered whether having e&p deployed during a storm is a good idea... I was caught in a massive storm in France so lifted mine just in case. I remember my dad always used to make us get out of the caravan and sit in the car during a storm.. I figured it was because of the legs rather than non-metal construction.

 

[Albacore]

I asked Ken and he replied "Close them no signal. Open them signal. I rest my case my Lord. If I put my phone in the roof light and hotspot from it it works well with them all shut."
Gonna have to try this for myself ;-)

Yep that's what I do, pop phone on the blind in the rooflight for the best signal.

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[bigtwin]

I wondered whether having e&p deployed during a storm is a good idea... I was caught in a massive storm in France so lifted mine just in case. I remember my dad always used to make us get out of the caravan and sit in the car during a storm.. I figured it was because of the legs rather than non-metal construction.

It makes no difference to the occupants as you're in a Faraday cage. It will probably help with the discharge path though.

Ian

 

[BikerJon]

Well, according to Ken from the YouTube channel "Life is too short" it does! Go into 8 minutes on this video -


Anyone know if he is right? Is the material they are made from not a sort of paper?

Never heard such rubbish, scientifically that's nonsense. On the losing mobile signal point, I use my mobile as a hotspot to tether the smart TV to. Never had any difference with the blinds open or closed. Maybe if they were granite walls rather than paper there might be a point .

 

[Pausim]

Never heard such rubbish, scientifically that's nonsense. On the losing mobile signal point, I use my mobile as a hotspot to tether the smart TV to. Never had any difference with the blinds open or closed. Maybe if they were granite walls rather than paper there might be a point .

I can’t agree with your statement about scientific nonsense.

Perhaps you don’t have foil backed blinds. Last night my download went right down when I shut the blinds, it returned when I popped my phone behind a blind and left a gap for it to hotspot with my iPad. Even our front windscreen blind contains foil but it is hidden inside the paper sandwich to stop nasty reflections. Armed with my scientific kit which includes a roll of kitchen foil I will now conduct an experiment.

With my phone sitting on the table next to me and my iPad connected by hotspot to it I got 3 bars of 4G and a download speed of 30 mbps. I then wrapped the phone in a single layer of foil leaving it in the same position and orientation. The phone dropped to 1 bar of 4G and the download speed plummeted to 6 mbps. I then unwrapped the phone and the signal strength returned to 3 bars of 4G and the download speed rose to 31 mbps.

Conclusion. These results are in keeping with the scientific principles of electromagnetism established by Michael Faraday in the 19th Century. The reduction in download could in part be due to reduced connectivity between phone and iPad but clearly the foil is interfering with the radio waves.

 

[Just smiffy]

I asked him why he had the steering clamp thingy on while they where in the van as a bit awkward in the middle of the night to get off in an emergency and he replied because it keeps it out of the way and is easy to get off…

 

[EML]

I can’t agree with your statement about scientific nonsense.

...

With my phone sitting on the table next to me and my iPad connected by hotspot to it I got 3 bars of 4G and a download speed of 30 mbps. I then wrapped the phone in a single layer of foil leaving it in the same position and orientation. The phone dropped to 1 bar of 4G and the download speed plummeted to 6 mbps. I then unwrapped the phone and the signal strength returned to 3 bars of 4G and the download speed rose to 31 mbps.

Conclusion. These results are in keeping with the scientific principles of electromagnetism established by Michael Faraday in the 19th Century. The reduction in download could in part be due to reduced connectivity between phone and iPad but clearly the foil is interfering with the radio waves.

Interesting experiment, but not quite right. You're conflating 3 different things: (1) reflection of EM signals from a conductive surface; (2) the skin effect distance; and (3) Faraday cages. For your case, if you actually had wrapped the phone completely in tin foil, I'd expect zero signal at the mobile phone (for complex reasons involving lots of sums). However, you say you saw "1 bar of 4G". How? Through a hole in the foil??

Specifically on Faraday cages: Unless you've found every hole in your van which has a size of a few cm or more, and put in a conductor to reduce the hole size significantly, then your van is not a Faraday cage, period (at least from the point of view of phone signals; see my post above). The phone signal will get in through the holes, and reflect off pretty much everything inside; this is why you have (some) phone reception in your (metal) van. It all depends on where your phone is, as lots of others have pointed out.

There have been any number of posts on this in the past. I remember one long thread on GPS signals which could, or couldn't, get through a windscreen. GPS has a longer wavelength than modern mobile phone signals (~20cm vs. 9cm for 5G) so it's easier to block GPS (fun fact: if you get a window seat on a plane, and hold your phone to the window, you can sometimes get a GPS fix all the way to the coast, or further if you have an offline map).

Back in the day I worked on building the first prototype 3G receivers. These actually depended on combining multiple reflected signals to get usable data. The reflections could be off anything: skyscrapers in a city, hills, whatever. Try repeating your experiment by holding the tin foil betweeen your (unwrapped) phone and the local phone mast. You should still get some signal, because of these reflections.

As an aside, Faraday was an experimenter, and discovered induction, among other things. James Clerk Maxwell pulled everything together to develop electromagnetism. Another fun fact: Maxwell developed his equations in the 1860s. They're relativistic (electricity and magnetism are the same thing, seen in different reference frames), but no-one noticed until Einstein came up with Special Relativity, 40 years later. Einstein apparently had pictures of both Faraday and Maxwell on his study wall (so says Wikipedia, anyway).

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[Pausim]

Interesting experiment, but not quite right. You're conflating 3 different things: (1) reflection of EM signals from a conductive surface; (2) the skin effect distance; and (3) Faraday cages. For your case, if you actually had wrapped the phone completely in tin foil, I'd expect zero signal at the mobile phone (for complex reasons involving lots of sums). However, you say you saw "1 bar of 4G". How? Through a hole in the foil??

I had wrapped the phone fairly comprehensively but not folded the ends as thoroughly as perhaps I could have. No window, I watched the signal strength from my iPad which shows this on the wifi selection list. I was just happy to prove that the foil did have an impact on the signal strength.