**Wireless Camera Experiment: A Technical Analysis**
As an electronics enthusiast, I recently embarked on a project to build a wireless camera system using a 5.8GHz VCO (Voltage-Controlled Oscillator) circuit. The goal was to create a compact and low-power design that could transmit high-quality video signals wirelessly. However, the journey was not without its challenges.
**Initial Obstacles**
The first hurdle I encountered was finding a suitable VCO chip that operated at 5.8GHz, which is the desired frequency for wireless camera applications. After extensive research, I discovered that achieving such a high frequency requires a super tiny inductance and/or capacitance, making it impractical to use traditional circuit designs.
**Introduction to Voltage-Controlled Oscillators (VCOs)**
I then turned my attention to VCOs, which are chips that can generate a specific frequency signal internally. By applying a DC voltage through the tune pin, the frequency of the output signal can be fine-tuned. This seemed like an ideal solution for my wireless camera project.
**Sourcing a 5.8GHz VCO**
After searching online, I found a 5.8GHz VCO on Aliexpress, which at first glance appeared to be a bit sketchy. However, the chip came with some documentation, so I decided to give it a try. After waiting two weeks for delivery, I finally received my VCO boards and began to assemble the circuit.
**Initial Testing**
According to the example schematic provided with the VCO chip, I only needed to solder additional bypass capacitors and an antenna wire to the board. To ensure optimal video signal transmission, I also created a small Op-amp circuit to adjust the camera's data signal between 2 to 5V. Once complete, it was time to connect the circuits and power them up.
**Testing the 5.8GHz VCO**
After searching through all the channels of my receiver goggles, I unfortunately only found traces of a signal, but no clear camera image. This led me to wonder whether the Aliexpress VCOs even worked at all. To confirm, I ordered similar VCO chips that operated at 2.4GHz, which is the frequency used by most WiFi connections.
**Testing the 2.4GHz VCO**
Using my oscilloscope's function generator as the input voltage for the VCO, I created a test circuit to prove whether the chip actually worked. By applying a specific frequency to the VCO, I was able to observe how it affected my WiFi connection on my laptop.
**Demonstration of the 2.4GHz VCO**
As you can see in this demonstration, the WiFi connection works perfectly fine until I turn on the VCO, which then messes up and completely interrupts the internet connection. This proves that the VCOs do indeed work.
**The Problem with the 5.8GHz VCO**
Now, I'm not entirely sure what's going wrong with the 5.8GHz VCO. Despite trying different approaches, such as switching to a 2.4GHz receiver and using another 2.4GHz VCO IC from Maxim, I still couldn't get it to work properly.
**Conclusion**
I hope this technical analysis has provided some insight into my wireless camera experiment. If you have any feedback or suggestions, please share them in the comments section. Until we find a solution, I'll have to rely on pre-made wireless video solutions. Thank you for watching, and don't forget to like, share, subscribe, and hit the notification bell. Stay creative, and I'll see you next time!
WEBVTTKind: captionsLanguage: enSooo this video quality is not really the best, right? But I think it is still pretty impressive when you consider that this small drone is sending it wirelessly to those receiver goggles.And needless to say I am currently obsessed flying my drone with these goggles on, because it is a unique experience to see the world through the eyes of a fast drone crashing most of the time.But while flying I realized that the wireless video connection does come with a limited range which not only got me wondering how this wireless video system works but also whether I can improve it. Now I would love to say that I managed to do just that, but in reality I spent a week testing different wireless video techniques only to end up with terrible results and a by-product which is a short range WiFi jammer that can mess up your internet connection. So if that sounds interesting to you then stay tuned because I will tell you exactly how I got to this point.Let's get started! This video is sponsored by Keysight who are currently looking for and hiring talented radio frequency, software and digital engineers in the USA and Germany. If that sounds like you then feel free to check out the video description because maybe you can find your dream job at Keysight. I wish you good luck. First off in order to get an initial idea how the wireless video system of my drone functions I obviously firstly took it apart in order to have a closer look at its camera. It comes with a total of 3 connection wires which are red for 5V, black for GND and white for the data line which after probing it with an oscilloscope looks like this on the screen. Now you might not know it but you probably already used such a signal before if you are familiar with old school CRT TVs like this one and of course such a yellow composite connector because yes; this is an old school analogue composite video signal. Each one of those „bursts“ I would call them comes with all the video information for one line of the CRT TV.We got the synchronisation part which indicates that a new line starts and afterwards the colour burst and the luminance levels which dictate the colour and brightness of each pixel.And of course they all come with varying voltage values to represent their brightness values because like I said before we are dealing with an analogue signal here.This signal then repeats depending on how many lines we are drawing on the TV and thus we got all the information for one complete picture. And if for some reason you don't believe me then let me just hook up my drones camera replacement data signal to my CRT TVs video input in order to prove my point in a more practical manner. OK, so now we understand what kind of video signal we are dealing with. But I still had no idea how the wireless communication looks like. So what I did next was examining all the IC labels on the drones PCB and googling what their purposes are. And I think this RTC6705 is the winner for me here because it is a 5.8GHz Band FM transmitter which as the datasheet states generates a 5.8GHz FM signal modulated by a video signal. That of course initially sounds complicated but in a nutshell the IC firstly creates a carrier signal with a frequency of 5.8GHz.Then we mix it up with our video signal which is the modulating signal and thus our IC now creates a new signal similar to the 5.8GHz one with the only difference that depending on the voltage levels of the video signal the frequency of the new frequency modulated signal changes up and down a bit. And I know that my FM aka Frequency Modulated signal is not very accurate here but bear with me. Because afterwards this FM signal gets send out through an antenna and picked up by the receiver goggles which also use the 5.8GHz waveform to then demodulate it and thus finally get the original video signal we started with.Of course the exact frequency can vary a bit but that is also why the receiver comes with a variety of channels that cover all possible frequencies around 5.8GHz.Now at this point the general functional principle of this wireless video system should be clear and I started to wonder how to improve it. And of course to get inspired I firstly asked google images where I mainly found this type of transistor amplifier circuit for this sort of application. What is basically does is creating a carrier signal through the help of an LC tank circuit whose resonance frequency is determined by the used inductance and capacitance. The video signal then modulates this carrier signal a bit in I think both an amplitude and frequency direction because let's face it; this circuit is rather simple and thus not optimal. But nevertheless I still gave it a try by creating my own handmade coil and soldering all components together in mid air to ultimately create this beauty. And after hooking up the the camera, it was time to power everything and see whether any wireless transmission to my old CRT TV was possible. After scanning the frequencies bands for a while I found something promising which definitely was related to my transmitter, but at no point was I able to see actual camera footage. And worst of all the used frequency was only around 7 MHz which is way way lower than the desired 5800MHz aka 5.8GHz we need for the goggles. To achieve such a high frequency though we would require a super tiny inductance and or capacitance and let me tell you right now that this is not practically achievable which basically means we can not use this type of circuit for the job. Instead I got interested in VCOs the datasheet mentioned which stands for voltage controlled oscillator.For example a 5.8GHz VCO would internally create a 5.8GHz signal whose frequency we could fine tune with a DC voltage through the tune pin. And thus on the output we would once again get the frequency modulated signal we were after from the beginning.So needless to say I searched for such a VCO next on the internet and really only found one on Aliexpress which at first sight seemed a bit sketchy but it at least came with a bit of documentation. So after ordering and waiting for two weeks I finally received my promised VCO boards which after removing one of the metal shields revealed some promising looking circuitry. So according to the given example schematic; I basically only soldered additional bypass capacitors to the board as well as an antenna wire. And after then creating a small Op-amp circuit for the cameras data signal in order to perfectly adjust the signal between 2 to 5V; it was time to connect the circuits and power them.At this point I desperately searched through all the channels of my receiver goggles and once again only found traces of a signal but not anything that would resemble a camera image which got me wondering whether these Aliexpress VCOs even work in the first place? To check that I ordered very similar ones that come with a frequency of 2.4GHz which is the frequency your WiFi connection uses most of the time. After building up a test circuit according to once again the given schematic; I this time used my oscilloscopes function generator for the tuning voltage input of the VCO. My goal here was to basically spit out noise that messes with the WiFi connection of my laptop in order to prove that those VCOs actually do work.That is why I will not tell you what exact frequency I am using for the tuning voltage because I do not want others to build this jammer. But then again it is also so low power that it only works properly around 20cms next to it. And as you can see in this demonstration the WiFi connection works perfectly fine until I turn on the VCO which now messes things up and thus completely interrupts the internet connection; meaning the VCOs do in fact work. So what is the problem with the 5.8GHz one you might ask? And I would have to confess that I am not entirely sure.Now of course I tried a few different other approaches with it, tried switching to a 2.4GHz receiver which also didn't work with the fitting Aliexpress VCO and I even tried another 2.4GHz VCO IC from Maxim which to my surprise actually delivered a part of the camera image but it still looked quite terrible. So all in all I think there is either a hole in my theory or I am missing something completely. Either way I hope you got some feedback for me in the comment section. Until we find a solution though I will have to get comfortable with pre-made wireless video solutions and I hope you at least learned something new through this video. If so consider supporting me through Patreon to keep the show going. Don't forget to like, share, subscribe and hit the notification bell. Stay creative and I will see you next time.
