Hi. In a previous video, you saw me install some LED panel lights on my roof here for shooting these videos. Ending: Click here if you haven't seen it. I'll link that one in now I showed that I actually had an issue with these crappy alloc remote control powerpoints that I got from the hardware store Bunnings here and they I'll show them working.

This is number one. This is number two. You can have up to four like this and you can turn it on and it actually has a relay in there which switches the output on so you can turn it off and on. No problems at all.

This second one, we can turn that off and on. no problems whatsoever. So everything's hunky-dory but if I take this remote control, you can't see it. but I'm taking it like a meter away.

I'm just holding it outstretched hand. It doesn't work anymore or it works a bit intimately. Only number two is working or sometimes and number one is not working at all. by right next to the camera now and number one won't work until I actually get in there like right close to it.

What the hell is going on now? Of course that seems weird because these don't transmit. these are just receivers. This is the transmitter here. So and they've been coded to work with different power points here.

Now you might think, well, if their receivers, what's the problem, huh? Something in the Powerball Because they're both on the same power board. Maybe there's something conducting here I Don't know, you know through the same power board? Well, I won't go through the methods to show that that's not true. Take my word for it. it is not an issue caused by having it on the same circuit, the same phase, the same power board, or whatever it has to do with the distance, the physical distance between these two units.

So I space them apart like this. As you saw, they both work. No problems whatsoever. I have the remote in the middle if I actually move this one over here so these are physically closer to each other.

Like this, you'll notice that number One it turned on, but it won't switch off properly only when I got closer to it and number two is working just fine. But number one is having a problem there. So what's going on here? Well, all has to do with the fact that these aren't even though they're supposed to be. They aren't just receivers.

Hmm, are you thinking what? I'm thinking. Yep. Pain-in-the-ass trap for young players. Super Regenerative receivers.

Try. say that's three times quickly. Super Agenda, sir. If the Super Regenerative I Give up.

Regenerative. Super Regenerative. Super Regenerative. Super Regenerative.

Super Regenerative. Super Regenerative. Super Regenerative. I'm gonna get it better over time.

So that proved that theory. I've got that. This thing uses a Regenerative Super or Super regenerative receiver that they're interfering with each other. Because a Super region? That's easier to say.

ha. Stick with that super region receiver. In these, they actually have an LC tank oscillator in them. and with action, which actually has positive feedback, they actually oscillate.

So when you've got an oscillator, if you don't shield that oscillator inside, it can actually transmit on basically the same frequency you're trying to receive. So these two receivers here are trying to receive on the same frequency and you don't design these properly to shield them and they're spewing out all sorts of RF energy at the frequency that you're trying to receive the damn thing on. Then of course they're going to have weird us problems where it doesn't receive like this because it's been swamped by the nearby device now I have actually checked once I separate these by about half a meter. They work fine from like right across the room and that's how I fix the problem in my roof.

So it's definitely a proximity effect. And just to show you about this phase thing, well, I've got one power ball connected to one side of my lab and the other one connected all the way over to the other side which is a different art phase here in the lab. and if I hit the button, hit the music. There we go.

Channel one is once again not working. Channel two works a treat and if I go over here, it just doesn't work. If I separate them like that. if I put part, then channel one will actually work anywhere.

pretty much anywhere in the room now, so no problems at all. But I must say I do notice a bit of a range difference when they are on different phases, so perhaps there is something to do with the fact that they might be on the same phase sharing either the same power board ultimately going back to the same phase in the same PowerPoint which they are up in my roof. So yeah, that has some effects. so maybe there's some RF are jumping onto the mains Warren as well.

but still, the proximity effect is definitely still there. So I thought we'd actually try and see if we can get anything if these things are transmitting anything. Now the frequency and we're looking at here is that four hundred and Thirty three Point Nine, two megahertz. So on my radio spectrum analyzer here I've set the center frequency at that and I've set a five megahertz that span here and I really can't see much there at all.

It's like right down in the noise so I was actually rather surprised by that. But I think we can do a bit better. and just to prove that we can actually see something here, we go: I've got to hold down the button of course to continuously transmit, but you can see the carrier frequency there. It's almost being on four, three, four, thirty three point Nine two.

So that's close enough and you can see no problems whatsoever. and I'm not sure about the modulation scheme used to select the different channels, but I'm not not concerned about that at all for our today's video. but you can see the carrier and the carrier will now just vanish. But we plug this thing in and no, I've tried it.

It doesn't make any difference if you have this combined and things like that, it doesn't actually do anything. It's all we can see is that transmitting from the transmitter as you'd expect, I'll show you how close it is. It's like sitting right on top of this thing. So yeah, the antennas like right on top.

but this thing does actually have a preamp in itself. We're going to amplitude and we go down here. We can turn on the RF preamp and that gives us like I don't know five or more DB down gain in there and we might be able to start see a hint of a couple of things here. Actually, silly me.

Had the reference level set for a 0. DBM If we go down to minus 30 DBM and I set my RF preamp on then Tada look, we can see some crap in this 5 megahertz spam we've got here around the fret look, we're getting some spikes in here and to prove that it is this thing, if I actually disconnect it like that boom look at that it's gone right? So now we're getting a huge bunch of I won't touch the antenna this time. I'll put it here. For example, plug it in and bingo look in the spike there and something there.

So we're getting. We're definitely getting something. And of course, if I switch the transmitter back on Mooshka, There we go. Ok I should expect his weight down while transmitting, but you can see that the receiver here is actually doing something because it's not shielded and the receiver has to be around that frequency.

so it's actually it's not that high. It's not that great, but anyway, we should be able to see something a bit more if we go over to the Tektronix scope and hopefully you can see that we're getting it a bit better here. We're getting quite a few spikes there. There we go it.

You know we're talking about - you know, 96 DBM You know, like it's really quite low and the receiver is just over that. Then once again, I'll prove it if I disconnect it. Boom right. It vanishes.

There's our natural noise floor with the antenna just sitting there on the bench like that and you plug this sucker in. and whoosh guy. we get that. see what happens if we plug 2 in.

Did that amplitude go up? But you know, like cuz they're gonna have slightly different frequencies, right? These things are not. They're not even crystal. They're not even going to be crystal controlled oscillators inside these things. So they're just going to be like I'm LC tank circuits basically so that are like hand I tuned most likely.

So yeah, we're getting something there so you can see that these things transmit and you can see that if I go down to a 100 Hertz some resolution bandwidth here. it's a bit slower on the update and of course as you'd expect. But yeah you can really see the peaks in here. so this thing is definitely transmitting across.

you know, a fairly broad band. It's not like scented like right on the receiver, but you know it looks like maybe the receivers here and it's well, it's going to be near enough to the transmitter so you know which is 435 0.92 there. and it's supposed to be four thirty, three, Point Nine two. But as I said I reckon these suckers have got crappy little hand tuned LC oscillators in them.

Mm-hmm you think I'm thinking yep Ted M if we take a look inside this sucker here it is and I had a bit of trouble getting into it because it used these stupid little last security screws, the one with the you know that little thing in there and just to stop you using a flat head. and of course I've got like a security bit set. No problems at all, but it was too recessed down in there. I could get these ones out, but I couldn't get these ones out so nothing you can't fix with a dremel.

No, because this thing is built down to a price. Yeah, we're not gonna see anything too fantastic in here. We've got the leads welded on to the contacts down in there. that's me and obviously flip it over the other side here.

I've got ourselves the the relay. That'll be a one hand. it's a punch in it's a hunch in yeah, super quality. Anyway, there's our real Oh it switches it off.

we're going to ourselves. hey hey decent. That looks like a recently quite a reasonable quality X-class I kept there, but basically there is not much else in here. This is I expected.

A little bit more than this, but a classic. A super regenerative circuit. Super regen. Circuit Art uses a single you can.

Well, you can do it with a single transistor. And bingo, there's our single transistor. Bingo! There is our tunable coil. and you'll notice as I suspected, no crystal in there.

None of that crystal rubbish. Inaccurate frequency, no siree. Bob A Just somebody in the factory just gets in there and gives that a little tweak with the correct turn angle. so these things are going to drift like there's no time.

Well, I'm not assuming that's gonna interest a lot. Maybe that's a maybe a bad assumption. but anyway. I'm yeah it's a single transistor LC tank oscillator basically.

and we've got some surface mount caps on the bottom there, so there's not much. not much doing there at all. I'm not going to bother a reverse engineering this thing. I Can pretty much guarantee that's a region circuit.

A region oscillator might get the part number on that transistor though. There we go. We've got ourselves a KSP 10 that's a UHF VHF RF transistor. No surprises whatsoever.

We've only got a couple of turns in that coil there and it's all a bit. How are you doing really? I Mean, but you know this is what your classic region circuit. Is this? nothing to it at all? Or do we have a diet in there who are fancy pantsy? And if you're wondering what that chip-ins sorry, it's a bit hard to get the number here, but I've looked at it's a classic Lm35 8. So yeah, nothing to do with the RF at all.

Maybe that's the demodulation part and that 8 pin s so down in there I've got no idea they've actually I can't see any number on that at all. I Think they've rubbed the number off there. Maybe it's like a little 8 pin micro or something perhaps. But of course, the takeaway from this is that there is no shielding in this thing.

There's nothing in the case at all. There's no you know, RF kin or anything shield in the region receiver at all with the antenna coming out. In fact, it may be wondering where's the antenna. Where's wally? Well, that's Wally right there using the the tank coil as the antenna.

So yeah, it's pretty dodgy. but you know these things are only designed for a short range. and they're you know, kind of sort of getting away with it. But yeah, when you combine the fact that yet doesn't have a real antenna on the thing and it's a region circuit which is an unshielded Regen circuit which is effectively are transmitting as lower-level as it is.

but still, when you put - all these things side by side, it's enough for them to interfere. And if you want to see inside the transmitter, well, here it is. A couple of coin cells in there and wow, look at single chip solution: Bob's your uncle? None of this stuff that we saw in the transmitter, So there's our antenna obviously just around there. It's AC Coupled runs around there.

They don't They haven't populated that part in there, so that's obviously it. Nothing fancy at all. I Don't think they'll be anything on the other side, so that's obviously some sort of our custom RF our transmitter chip to do this. Oh, actually, this one's fancy.

Pantsy that crystal. 30 megahertz. But let's get in there and get the exact frequency. Thirteen Point Five Six you'll find that will be a multiple of our transmitted frequency.

And bonus points for anyone who can do that calculation in their head. you might do a rough calculation, but Thirteen Point Three, six Megahertz are five. Six megahertz. sorry is exactly one thirty tooth one.

Thirty seconds of 433 Point Nine two. So obviously they've got a yard thirty-two times multiplier in there. Now hold on to your hats. This is fascinating assumption that this is some sort of RF you know custom.

RF remote device is wrong. That is just a whole tech. 4801 OTP Micro There is no RF circuitry here at all. I don't see any external transistors.

There was nothing on the top side at all. Unbelievable. They must just be relying on the harmonics of the pumping out of square wave. It gotta be me actually what I'm doing now I Got the scope on directly probing the output of this thing and we're like down to ten millivolts per division.

So it's not just pumping a square wave into there. If we go right in, this won't have the memory resolution, but yeah, look, we can actually see the carrier frequency. This is sorry. this is only a 200 megahertz scope.

I Could use a higher bandwidth one. but yeah, basically we are seeing a 433 megahertz carrier there. It's about two nanoseconds per division, so it's going to be Lea No. 2.3 nanoseconds for that for 33 megahertz.

so that that matches up so we are actually seen. we are actually seeing the carrier frequency there. It's not just a harmonic, they're doing something there to convert that. Don't know? I Figured it out.

This is the standard whole tech up microcontroller, but the T3 on the end of the part number there I was looking at the wrong datasheet. The T3 is a separate chip with, you guessed at a building RF transmitter. don't ya whole tech make these arm custom my grows with RF transmitters pretty much specifically for this sort of application and I was just thinking, well how do they combine that microcontroller with the RF transmitter It's sort of, you know, and they're not sort of like very compatible while silicon type processors. but hey, look, it tells you they've actually got a dual die package their separate RF transmitter die.

So I'm actually rather surprised at the simplicity of this. A lot of region receivers I've seen actually have a transformer in them, so yeah, this one doesn't. it's just a yeah, just literally a single transistor. We've got a couple of caps, we've got a a coil forming and Elsie resonant teen circuit and Bob's your uncle and just to prove that separating them a distance actually works there we go: I've got them like just under a meter apart and of course I can switch one on, two on one off two off.

It's fine and I'll walk halfway across there. well the other side of the room here like five meters away and that's see if I can do it. So here we go: I'll turn one off, one, two, one two. There we go all I can switch both is like an old button.

There we go and there's an off button. slight problem with receiver number one there. So yeah, it's still not the best, but it definitely fixes up in the lights. I put them like this far apart up in the roof and that fixed all my problems.

So it still is a bit of a bit of an issue. but you know, definitely not like it was before you. But ultimately, what I think's happening here is not so much like these spikes. It's basically that these things are generating broadband noise.

Pretty much that's actually raising the noise floor. I mean you've got a tiny little pissant coil in there trying to act as the antenna and you've got a little you know, pissant transmitter like this. It's just totally poor system design and by broadband noise, I can show you what I mean by this. So I've got my nice little tech box near Fear Probes here.

I Got one of my magnetic H field probes hooked up to my 3d wideband amplifier here and let's take a look at it on the Rygel here. I've got it hooked up. Of course you get nothing close, but when you get in here Oh actually I have to pull back on that sorry when you get in here and magnetically couple that in. you can see this is a 500 megahertz span so that's 50 megahertz per division there on the X-axis so you can see how broadband this noise actually is.

Sure it's centered on that. I carry a frequency? I've actually got it centered on 433 0.92 here. Oops, it's not a lawyer, but yeah, it's centered on that. but look how broadband that is.

It's absolutely incredible. And if I press the transmitter of course, yeah, we get our little spike in there. but look, it's just. it's very touchy to try and pick that up.

But yeah, there we go because the coil is right in this corner here. If I put it in this corner where basically we don't pick that up very well, too well at all. So trying to pick up the magnetic field from that coil and it's just massively why band. So these things just horribly designed just generating lots of wideband noise which swamps the tiny little signal coming from this transmitter.

so if you're having to close together, yeah, one or both of them can actually play up. Now of course we can go to town trying to analyze this and get in in a proper measurements and now checking the the modular how they're doing the modulation for the different channels and all sorts of stuff like that. and I couldn't be bothered. I Just wanted to verify that this thing was actually putting out something even though it's a very low level and that's what we could see on the art scope.

but it was more than enough to cause problems when you put these things close together like this. And it's a very well-known problem with these things apparently, and a lot of people are said this straight away. When I did the previous video, they said just physically separate them like this and problem solved And you know at first thought you might think that's stupid because these are receivers. What difference does it make how close the receivers can be? Well, piss-poor designed like this with no shielding.

Not that it is currently anything wrong with a region circuit like this, but you've got to design it right. It's all about the systems engineering and getting the damn thing right. and these things that built for a couple of bucks down to the piano. the manufacturing cost on these.

there's a couple of dollars. Build them right down. you know it shaved every last cent off the thing. and well, you can't put a metal can on it.

Oh no, siree. Bob that a waste couple of cents. Screw that. So they've just gone for the absolute simplest design.

They could single transistor super regen circuit in there and well, they radiate a bit and cause interference. There you go track for young players. So I hope you found that interesting. If you want to discuss it, jump on over to the Eevee blog forum links always down below.

Catch you next time you.