I was talking with my neighbor, with walkie talkies, and behind me, at a certain moment, turn on the flashlight that normally use to go in the basement, I turn, I continue to talk, and I see that the flashlight turns on, turns off, changing level. I see that works in conjunction to how I use the walkie talkie; here is a short video.
The flashlight has electronic switch; I tried it on two different flashlight, always with electronic switch, but they were not affected; for now it is only this that has the problem.
I’m a HAM… so? i’ll take a stab at guessing this out…
odd things in real life can act as an antenna… and if something comes up as a 1/4, 1/8th, etc etc sub-multiple of the right length (or close to it) of the radio frequency….
a trace or a wire or something in the flashlight is just the right length, and picking up the radio signal… and its tripping the low voltage signal line the electronic switch operates. Or, i guess maybe its tripping the “de bounce” circuit on the switch…
i would assume maybe if its not the body of the tube acting as a physical waveguide, that you could poke around with a decent oscilloscope and locate the signal with careful poking and looking, try to trace it down…
Hey I have a light that looks exactly the same.
Is your head also plastic?
In mine it is so the head and handle do not shield the electronics
Will try this later and report back if it works here as well though I only have a simple cheap walkie talkie set (specs say 5km bit I did not test this nor believe it for that price)
Edit nope tried different channels nothing switching on
This may be annoying and somewhat weird. But how cool is that!!! A remote controlled flashlight….
I say lucky find.
But I agree, you can get very odd things happening with radio frequencies sometimes. I once picked up the control tower from a local international air port with a guitar amp and lead plugged into my electric guitar.
I’m no expert but I’m gonna take a stab at part of it. A usual flashlight body (enclosed metal tube) acts as a faraday cage and seals the driver from external signals. Your particular light has a handle but also has an electronic switch in the handle that connects directly to the driver. This handle acts as an antenna since it’s outside the faraday cage and the electronic switch is receiving signal bursts from your walkie that are tricking your driver into thinking you are pressing the electronic switch. If your light had a mechanical switch in the tail it wouldn’t work like that. Pretty cool trick though. Might be very useful when camping. Would be sweet if it worked with voice commands too.
Some fun things I’d be curious of were I you…
What is the working range?
What happens if you change channels on your walkie? Does it work on just one channel frequency or several?
Thank you for your speech; the only flashlight I know who are, by design, a Faraday cage, are the HDS; all other flashlights, having the negative ground, no Faraday cages.
That flashlight has part of the body in plastic and many wires that may be an antenna.
My Walkie Talkie has 16 channels; 8 PMR, and 8 LPD, (is reprogrammed), and the flashlight will turn on with all the channels.
I’m doing tests with all the other flashlight with the electronic switch, for now they are not influenced by the frequency of W.T.
It would be a problem if using the W.T., you turn on the flashlight in my backpack.
It would be a problem even with the tactical use, …. at night.
1/8 wavelength is not a good antenna and 1/4 needs a ground plane. But the fatter the “wire” the broader the bandwidth, and it is very close. How the waves get inside is more of a question. Maybe one of the joints is anodized.
QUOTE
1/8 wavelength is not a good antenna and 1/4 needs a ground plane. But the fatter the “wire” the broader the bandwidth, and it is very close. How the waves get inside is more of a question. Maybe one of the joints is anodized.
ENDQUOTE
uhm… my thoughts?
just about anything “metal” in an antenna… it just might not be a very GOOD one, and, it might not have anywhere to send the signal to “do anything”…. but, you dont have to be tuned in length specifically to frequency when you are in the near field…
if you are in the near field?? you can take the antenna OFF the radio and pick up the signal perfect. When you are in the near field? The guy can be transmitting in FM, and you pick him up clear as a bell in AM mode…
also, any piece of metal long enough will pick up ALL frequencies beneath the length… its the principle of the long wire…picks up everything (including noise though, lol)
my point is? if you have almost any piece of metal? and theres a transmitting radio nearby? its being picked up by the pieces of metal… if you dont believe me? take your oscilloscope and “sample” just about anything when a radio is transmitting close by… being in the near field is pretty cool… HT’s are fairly high enough in frequency that comparatively short pieces of metal will pick up a signal fine, let alone being in the near field. Length tuning is only for discrimination and trying to peak signals of interest…. but for reception? pretty much anything goes… especially with how short the wavelengths on HTs are…
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PS - what exactly do you mean by saying 1/4 wave needs a ground plane? reception is easy, any piece of wire or chink of metal will do it.
i am thinking this is all because the flashlight is popping in the near field…
PPS - faraday cage? my understanding was that any “metal container that was grounded” would act as a faraday cage (faraday shield)
if the flashlight tube is grounded? it would be a faraday shield?? BUT… only if all holes in the metal container were smaller than the frequency you want to keep out… you got your power button hole, your open front of the flashlight…
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all one would have to DO to see what was going on exactly? would be to carefully “probe” with an oscillioscope… you will quickly find what piece of the flashlight is peaking the best signal…
