This may not be a new fact to know, but interestingly: Jagadish Chandra Bose used a similar topology for generating 5 mm waves in his laboratory in 1894. Of course it was not a regular lumped LC-circuit, but the resonator excitation was also made with spark-gap. Once again: 60 GHz. Consciously, with measurement. 1890s.
I remember having a drawing of how to use a spark plug on a marine motor to make an emergency radio signal......kept the small drawing in my billfold during my boating years but lost it. would like any info on making an emergeny xmitter using an outboard or inboard marine engine
Interesting question. I'd have to try it. Actually, I'll put it in a GTEM cell in a bit and see how nasty this thing is in a professional EMC measurement set-up.
This is a great video, thanks. Do you know why the Q factor is so "bad", only 11? The inductor is almost "ideal" (coil with air core). What is causing so much dumping? Thank you for explaining why the first 2 cycles are weird. Some times ago I was looking at the same screen you have, and was puzzled by those.
Thanks for the sub! The spark gap itself is mostly to blame for the low Q. It stays conductive for longer than ideal. Therefore, in commercial spark gap transmitters back in the day, making sure the spark is distinguished as quickly as possible, is a key part of the design.
@@BalticLab thanks. However, I am not entirely sure about it because, if your theory is correct, wouldn't the dumping ratio improve after the spark is ended? In my case, I saw the same poor Q and also the *SAME* shape of the first 2 cycles) without using a spark gap. Instead I started the oscillation by "stimulating" the inductor of the LC tank by driving a nearby inductor (magnetically coupled by proximity) with a fast-rising slow-frequency (like 1khz) square wave. Would be interesting to test your hypothesis. Great videos, man!
@@BalticLab Thanks! It would be amazing if you can do that, as I have been experimenting with Q-measurements recently (to learn) and I could really benefit from watching your approach! Beside measuring the Q with a VNA, it would be interesting to measure the length of the spark and then go back to check your theory: once the spark has finished, if you are right, I guess we should witness on the oscilloscope a sharp increase in Q!
It's DC. You'll see a lot of different numbers between 1 kV/mm and 3 kV/mm. With some rounding your 20 kV/mm would be in that neighbourhood. The breakdown voltage depends on a lot of things. And it depends what your goal is. If you want to prevent breakdown and be on the safe side, sure, assuming 20 kV/inch is a good idea. If you want breadown to occur, 76 kV/in. is the better idea. That said, it depends on the temperature, humidity, exact gas mixture (which isn't even constant with air), pressure, etc. And it also depends a lot on the exact electrode spacing and shape. The false assumption is usually, that the measurement, be it 20 kV/in. is a linear one. Implying that for two inches 40 kV would be needed. But that is incorrect. The breakdown voltage at 10mm is different than at 25.4mm (1 inch), even if normalized to kV/in. The figure I've given is the accepted value derived from Paschen's law at standard conditions, a homogenous field and an electrode spacing of 10mm. If you're interested in this subject, feel free to subscribe as there's going to be a video on this exact subject coming up soon.
Very interesting video indeed. I have a random question though, do you know, how easy is it to buy common chemicals like acids exc for hobby use in Germany ? (without any license or chemistry phd).
It really depends on what exactly you want to buy. Unfortunately, Germany has very strict laws on chemicals in the hand of private individuals. A lot of those restrictions can be circumvented by registering a business and now being a commercial customer. A reliable source is Laboratoriumsdiscounter: www.laboratoriumdiscounter.nl/ Their range of products is a good indication of what the rules here in Germany / EU are. By using the discount code "BALTICLAB", you can even get 10 % discount.
Yes I did, however, I tried manually normalizing it a bit as the AI suggestion from my original text sounded way tooo unnatural. When I am in a writers block I tend to write my coarse thought, let AI optimize it and then - depending on what it generates - I either use the suggestions to eleviate my writer's block or use it. I thought this into text was a bit over the top, but hey, it works :D
You'd be correct, at least in the USA. Luckily, I live in Germany. Though this is probably one of maybe only a handful of things that we are allowed to do that Americans aren't. :)
Technically illegal for all signatories of the ITU treaty. But that bans them for only radio communication and broadcast purposes. An experiment like this would be absolutely fine in the US. Otherwise every stick welder and tesla coil would be a crime.
I am not a signatory of the ITU treaty though. Germany is, which didn't specifically ratify it into enforcable law. But you're right, the purpose is key, one could even question if any rules beyond "unintentonal radiator" rules apply to this demonstration.
Solid video covering the basics of a classic circuit for beginners 👍
Glad you liked it! I've been subscribed to your channel forever, so I am very happy to see you coming across one of my videos.
Wow, still online. Nice. Happen to know where that video of using a piezo lighter to make a simple transmitter is?
😢
@@BalticLabp😅😢of
Y😢ggyg😢gg
Excellent demo. A great example of applied mathematics
Thanks Richard, glad you liked it! 73s de AI5GW
This may not be a new fact to know, but interestingly: Jagadish Chandra Bose used a similar topology for generating 5 mm waves in his laboratory in 1894. Of course it was not a regular lumped LC-circuit, but the resonator excitation was also made with spark-gap.
Once again: 60 GHz. Consciously, with measurement. 1890s.
Very interesting information. Thanks for sharing!
Don't forget feed horns and the demonstration of cross polarization transmission loss.
now i can start trolling friends with that
Great Job. Keep it up 🎇🎇
Thank you! 😃
I remember having a drawing of how to use a spark plug on a marine motor to make an emergency radio signal......kept the small drawing in my billfold during my boating years but lost it. would like any info on making an emergeny xmitter using an outboard or inboard marine engine
That's a very interesting idea.. Since I have an outboard engine on my sailing yacht, I'll put that on my to do list for interesting ideas.
Outstanding video!
How much grounded aluminum shielding would it take to shield the circuit from itself?
Interesting question. I'd have to try it. Actually, I'll put it in a GTEM cell in a bit and see how nasty this thing is in a professional EMC measurement set-up.
This is a great video, thanks.
Do you know why the Q factor is so "bad", only 11? The inductor is almost "ideal" (coil with air core). What is causing so much dumping?
Thank you for explaining why the first 2 cycles are weird. Some times ago I was looking at the same screen you have, and was puzzled by those.
PS: Subscribed! Thanks again!
Thanks for the sub! The spark gap itself is mostly to blame for the low Q. It stays conductive for longer than ideal. Therefore, in commercial spark gap transmitters back in the day, making sure the spark is distinguished as quickly as possible, is a key part of the design.
@@BalticLab thanks. However, I am not entirely sure about it because, if your theory is correct, wouldn't the dumping ratio improve after the spark is ended?
In my case, I saw the same poor Q and also the *SAME* shape of the first 2 cycles) without using a spark gap. Instead I started the oscillation by "stimulating" the inductor of the LC tank by driving a nearby inductor (magnetically coupled by proximity) with a fast-rising slow-frequency (like 1khz) square wave.
Would be interesting to test your hypothesis.
Great videos, man!
That's interesting. I might have to investigate further on this and measure the Q without the spark gap using a VNA.
@@BalticLab Thanks! It would be amazing if you can do that, as I have been experimenting with Q-measurements recently (to learn) and I could really benefit from watching your approach!
Beside measuring the Q with a VNA, it would be interesting to measure the length of the spark and then go back to check your theory: once the spark has finished, if you are right, I guess we should witness on the oscilloscope a sharp increase in Q!
3KV/mm is interesting is that AC? I was taught the dielectric breakdown of air was 20KV/inch DC which is about 800V/mm DC. 3KV*25.4=76KV/In.
It's DC. You'll see a lot of different numbers between 1 kV/mm and 3 kV/mm. With some rounding your 20 kV/mm would be in that neighbourhood. The breakdown voltage depends on a lot of things. And it depends what your goal is. If you want to prevent breakdown and be on the safe side, sure, assuming 20 kV/inch is a good idea. If you want breadown to occur, 76 kV/in. is the better idea. That said, it depends on the temperature, humidity, exact gas mixture (which isn't even constant with air), pressure, etc. And it also depends a lot on the exact electrode spacing and shape. The false assumption is usually, that the measurement, be it 20 kV/in. is a linear one. Implying that for two inches 40 kV would be needed. But that is incorrect. The breakdown voltage at 10mm is different than at 25.4mm (1 inch), even if normalized to kV/in. The figure I've given is the accepted value derived from Paschen's law at standard conditions, a homogenous field and an electrode spacing of 10mm. If you're interested in this subject, feel free to subscribe as there's going to be a video on this exact subject coming up soon.
Very interesting video indeed. I have a random question though, do you know, how easy is it to buy common chemicals like acids exc for hobby use in Germany ? (without any license or chemistry phd).
It really depends on what exactly you want to buy. Unfortunately, Germany has very strict laws on chemicals in the hand of private individuals. A lot of those restrictions can be circumvented by registering a business and now being a commercial customer. A reliable source is Laboratoriumsdiscounter: www.laboratoriumdiscounter.nl/ Their range of products is a good indication of what the rules here in Germany / EU are. By using the discount code "BALTICLAB", you can even get 10 % discount.
@@BalticLab thanks i might use that in the future. Btw did you use AI for some of the video decription 😅
Yes I did, however, I tried manually normalizing it a bit as the AI suggestion from my original text sounded way tooo unnatural. When I am in a writers block I tend to write my coarse thought, let AI optimize it and then - depending on what it generates - I either use the suggestions to eleviate my writer's block or use it. I thought this into text was a bit over the top, but hey, it works :D
Can the spark gap be enclosed in glass with a gas that can control the spark better?
Absolutely! As a matter of fact, controlling spark gaps with gas pressure will be the subject of an upcoming video. So stay tuned. 😊
@@BalticLab Thanks!
I had always thought these were illegal to operate. Is this not true?
You'd be correct, at least in the USA. Luckily, I live in Germany. Though this is probably one of maybe only a handful of things that we are allowed to do that Americans aren't. :)
Technically illegal for all signatories of the ITU treaty.
But that bans them for only radio communication and broadcast purposes. An experiment like this would be absolutely fine in the US.
Otherwise every stick welder and tesla coil would be a crime.
I am not a signatory of the ITU treaty though. Germany is, which didn't specifically ratify it into enforcable law. But you're right, the purpose is key, one could even question if any rules beyond "unintentonal radiator" rules apply to this demonstration.
😢