Відео

Apologies and definitely not the intent - more than happy to take questions here or on Discord!

It could work as is in theory. Provided there is a strong HF source, and the reference and surveillance antennas support the HF frequency of choice. Just need to change the config file to the correct bandwidth and center frequency.

Fair call, it will degrade over time. I want to change the nylon bolts to stainless steel, then space out a 3D printed plate so the bolt doesn’t touch the boom.

I do. Not shown but a meter away from the antenna interface box is the house ground rod. I still haven’t run a cable connecting the body of the box to ground, but will soon.

@@30hoursdev I would not use a common rod for both because of the voltage which would be developed across the rod and its connections in a lightning strike. It would be much better to have a separate rod and then connect from box to its own rod and from that rod to the building ground system.

@@sbreheny I thought I could introduce a ground loop by having 2 ground rods, is that possible? But I’m definitely not an expert in that.

The 13 dB of gain from this Yagi help to increase the target signal in the direction it’s pointed. In my case it’s pointed along the aircraft landing path. In general one may make use an array of antennas to get the benefits of high gain as well as maximal coverage.

​@@30hoursdevAh, thx.

It's not truly "passive" there is an active component to this being transmitted at 204.64MHz.

Also not that it matters too much in this application, but a gamma match at that antenna feedpoint is an option to match that feed line to that lower impedance.

Lots of radar theory online and in textbooks. However I would recommend getting your hands dirty playing with signals first. Buy a RTL-SDR to record RF samples, and use GNU Radio to try and demodulate FM radio (lots of other videos showing this). I’m also (slowly) adding challenges in a signal processing CTF at learn.30hours.dev which can be solved in Python, MATLAB or the language of your choice.

Star trek teleport on peut rêver 😂

The Yagi has a VSWR of 1.7 and it’s receive only. My mismatch loss is much much less than my cable loss from 15 m of RG-58.

@@30hoursdev hey bro.. f the SWR.. the beta match is for making RX /(tx) from A-SYMMETRIC TO SYMMETRIC .. using a halfway with a gamma match had eliminated the asymmetric vs symmetric .. not that SWR ain´t important but it would have same SWR with the Match don right .. i often wonder why ppl on youtube always leeve out the betamatch .. making the antenna work on both side not only on the RX or TX side (radiator and tx side) doe´s it make sense that you dont utilize the shielded / grounded side until the betamatch is applied.. just saying .. it is you´r antenna.. but if you put it truh a smith diagram on a rotor .. you would see the antenna with out betamatch is asymmetric not symmetric in tx .. or rx .. Rothammel ARRL Jessup antenna books funny enough state the same... so i bet they are right...

@@kennethschultz6465 bro u are methed tf out lmao

Working on it. The 2x Rx Kraken is straightforward. The 5x Rx Kraken will be 4 channels for the surveillance array. I’m planning to rewrite the acquisition code (the Heimdall DAC that Kraken provides) before integrating in this code base.

@@30hoursdev Oh you have one?

That would depend wouldn't it?

That’s all Aussie cops for you. They think they’re above the rest of us, rather than serve us.

As a German I honestly can't understand the problem there. The information that police transmit is sensitive both for the individuals it is about as well as for themselves. Most matters that I would call the police for or might have the police called for on me would pertain to very much private matters. I wouldn't want some radio geek to listen in on them transmitting a report that contains my name, adress, date of birth and some recent, potentially quite intimate event. Just imagine that you were wrongfully suspected of having committed some serious crime or were even arrested for it - would you want the entirety of your friends and family and especially your employer to know? Even if it turned out to be nonsense quickly, you still would have a hard time shaking off the rumours that come afterwards. If you were the victim of a serious crime, would you want everyone and their dog to know? I wouldn't want the entire world to know if, say, I was the victim of a sexual crime. Next of course police do have an interest in keeping their conversations secret. There would be no use in setting up, say, speed cameras if everyone immediately knew where they are. Or it would be quite the unfair advantage, if a bank robber could listen in on police radio where officers try to coordinate their response. Those who do have a genuine and legitimate interest in getting police conversations should of course have the means to access them, e.g. through court orders in discovery, but I think police have a very good point in keeping their communication secret.

@@whynotjustmyusername It’s not conversations you peanut, it’s the location of their aircraft. It’s dangerous and silly that they don’t run transponders, while the RAAF happily does so above my city.

@@whynotjustmyusername They are public servants responding to public events, in public. Nothing about their actions should be hidden, except in extreme case, like attacks by organizations. I wouldn't want some German who thinks "radio geeks" shouldn't be able to listen to public servant communications making any decisions about this in my country, and I'm glad I don't have to deal with it.

@@whynotjustmyusername Speed Cameras are not allowed in many states.

It was convenient since I already had the coaxial run done. It was neater to keep everything over coax rather than add new connectors to the antenna interface box. Polarity does matter, ground is connected to the cable bulkhead, so you don’t want 5V shorting out there. Keep the 5V on the inner conductor.

He doesn't have one.