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Drone on Drone Warfare, With Jammers

After the alleged drone attacks on London Gatwick airport in 2018 we’ve been on the look out for effective countermeasures against these rogue drone operators. An interesting solution has been created by [Ogün Levent] in Turkey and is briefly documented on in his Dronesense page on Crowdsupply. There’s a few gaps in the write up due to non-disclosure agreements, but we might well be able to make some good guesses as to the missing content.

Not one, but two LimeSDRs are sent off into the air onboard a custom made drone to track down other drones and knock them out by jamming their signals, which is generally much safer than trying to fire air to air guided missiles at them!

The drone hardware used by [Ogün Levent] and his team is a custom-made S600 frame with T-Motor U3 motors and a 40 A speed controller, with a takeoff weight of 5 kg. An Adventech single board computer is the master controller with a Pixhawk secondary and, most importantly, a honking great big 4 W, 2.4 GHz frequency jammer with a range of 1200 meters.

The big advantage of sending out a hunter drone with countermeasures rather than trying to do it on the ground is that, being closer to the drone, the power of the jammer can be reduced, thus creating less disturbance to other RF devices in the area – the rogue drone is specifically targeted.

One of the LimeSDRs runs a GNU radio flowgraph with a specially designed block for detecting the rogue drone’s frequency modulation signature with what seems to be a machine learning classification script. The other LimeSDR runs another *secret* flowgraph and a custom script running on the SBC combines the two flowgraphs together.

So now it’s the fun part, what does the second LimeSDR do? Some of the more obvious problems with the overall concept is that the drone will jam itself and the rogue drone might already have anti-jamming capabilities installed, in which case it will just return to home. Maybe the second SDR is there to track the drone as it returns home and thereby catch the human operator? Answers/suggestions in the comments below! Video after the break.

Our very own Jenny List covered the Gatwick drone sightings in some detail: London Gatwick Airport Shuts Its Doors Due To Drone Sighting and Debunking the Drone Versus Plane Hysteria.

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Lucid Dreaming | Trying to Wrap My Head Around FILD

I have been attempting FILD for 3 days and I find the finger movements to be a good anchor for keeping the mind aware during the transition into sleep. I did experience some extreme hypnogogia like a loud ringing noise, and intense visualizations that became real during finger movments. This is a common feeling for me during WILDs and DEILDs. So out of the 3 attempts I went lucid once, failed the second attempt because I couldnt keep my adrenaline from rushing due to all the extreme hallucinations which caused me to wake up, and the third one I just fell asleep.

Most users report doing the finger method for 10-30 seconds and doing a reality check. And achieve a false awakening. They dont feel any transition at all. Which I find very strange.

Its hard for me to explain my train of thought around why FILD works the way it does for people, so Im just going to ask a bunch of questions.

Do you feel the transition during FILD attempts or just a false awakening?
Why stop finger movements after 30 seconds?
Why attempt a reality check after 30 seconds and not a longer period of time?
The reason I ask these questions is because FILD is the only WILD technique that Ive read that has a time limit. For example alot of people use visualization to WILD. This does not involve a time and just involves visualizing something until it becomes real. To me I would think alot of people fail this technique because of 10-30 seconds followed by a reality check step.

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3D Printing An Old-School Coherer

Coherers were devices used in some of the very earliest radio experiments in the 19th century. Consisting of a tube filled with metal filings with an electrode at each end, the coherer would begin to conduct when in the presence of radio frequency energy. Physically tapping the device would then loosen the filings again, and the device was once again ready to detect incoming signals. [hombremagnetico] has designed a basic 3D printed version of the device, and has been experimenting with it at home.

It’s a remarkably simple build, with the 3D printed components being a series of three brackets that combine to hold a small piece of plastic tube. This tube is filled with iron filings, and electrodes are inserted from either end. Super glue is used to seal the tube, and the coherer is complete.

The coherer can easily be tested by measuring the resistance between the two electrodes, and firing a piezo igniter near the tube. When the piezo igniter sparks, the coherer rapidly becomes conductive, and can be restored to a non-conductive state, or de-cohered, by tapping the tube.

Coherers and spark-gap sets are fun to experiment with, but be sure you have the proper approvals first. Video after the break.

 

 

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Lucid Dreaming | Back In the Game

Hey guys,

I got into lucid dreaming 7 years ago when I saw Inception and joined this website around that time. After alot of help from this site, at my best I could lucid dream almost every day sometimes 3 times a day for about 2-3 months. I did pretty much every technique, and had as many WILDs as DILDs. However, I was practicing ADA and RCs constantly throughout the day, while going to school/work and ended up joining the military. So, it was too mentally taxing for me to keep a dream journal and keep practicing, which led me to stop doing it because I had experienced my goals when it came to lucid dreaming.

But now I have some time to myself where I can put in the effort again to start experience lucidity like I used to, but I really want to get back into WILD/DEILDs again. I started my dream journal again, and do some RCs throughout the day.


Ive been at the journal for a week now, and have constantly trying to perform my WILD/DEILD techniques and ive failed everyday for a week. Im trying to incorporate CANWILD because I was awesome at DEILDs. Today, was the closest yet but was too excited to transition during my DEILD.

Been looking over my old threads to help me out, but has any new information or highly successful techniques that have been posted within the last few years?

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Adding LoRa Long Range Radio To Smartphones And Connected Devices

Would you add another radio to your smartphone? No, not another WiFi or cellular radio; a smartphone already has that. I’m talking about something that provides connectivity through ISM bands, either 433 or 915 MHz. This can be used where you don’t have cell phone coverage, and it has a longer range than WiFi. This is the idea behind the LoRa Sleeve, a messaging system that allows you to send off-the-grid messages.

The LoRa Sleeve is an ESP32-based hardware modem that can communicate with a smartphone, or any other device for that matter, over Bluetooth or USB. Inside, there are two modules, an ESP32 WROOM module that provides the Bluetooth, WiFi, USB connectivity, and all of the important software configuration and web-based GUI. The LoRa module is the ubiquitous RFM95W that’s ready to drop into any circuit. Other than that, the entire circuit is just a battery and some power management ICs.

While LoRa is certinaly not the protocol you would use for forwarding pics up to Instagram, it is a remarkable protocol for short messages carried over a long range. That’s exactly what you want when you’re out of range of cell phone towers — those pics can wait, but you might really to send a few words to your friends. That’s invaluable, and LoRa makes a lot of sense in that case.

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The Power Of Directional Antennas

AM broadcasting had a big problem, but usually only at night. During the day the AM signals had limited range, but at night they could travel across the country. With simple wire antennas, any two stations on the same frequency would interfere with each other. Because of this, the FCC required most radio stations to shut down or reduce power at night leaving just a handful of “clear channel” stations for nighttime programming. However, creating directional antennas allowed more stations to share channels and that’s the subject of a recent post by [John Schneider].

When it comes to antennas, ham radio operators often think bigger is better. After all, hams typically want to work stations far away, not some specific location. That’s not true in the commercial world, though. The big breakthrough that led to for example cell phones was the realization that making smaller antennas with lower power at higher frequencies would allow for reuse of channels. In those areas the focus is on making cells smaller and smaller to accommodate more people. You can think of AM broadcasting as using the same idea, except with relatively large cells.

A lot of innovation occurs when someone is angry about something as was the case here. Two cities in Florida shared a common radio transmitter in 1927 to promote tourism in the area. Because of the wide area coverage, people from far away could hear the benefits of a Florida vacation. However, a reorganization of the AM band in 1929 caused the Florida transmitter to interfere with a station in Wisconsin who complained.

As a result of that complaint, Florida had to cut their nighttime power and as their whole goal was to attract tourists from other states they were not happy. The Florida stations — WFLA and WSUN — contacted a consulting engineer named Craven to solve the problem.

What follows is an interesting study in RF problem solving, and while the answer might seem obvious today, it was pretty amazing back in the early 1930s. Without directional antennas, the 15,000 or so full-power AM radio stations in the United States at its peak would not have been possible.

If the AM band ever goes completely away we’ll be sad because it is the easiest thing to receive with a crystal radio. Of course, then you could just broadcast yourself, we suppose.

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The Backbone Of VHF Amateur Radio May Be Under Threat

A story that has been on the burner for a few weeks concerns a proposal that will be advanced to the ITU World Radiocommunication Conference 2023. It originates with French spectrum regulators and is reported to be at the behest of the Paris-based multinational defence contractor Thales. The sting in its tail is the proposed relegation of amateur radio to secondary status of the widely used two-meter band (144 MHz) to permit its usage by aircraft. The machinations of global spectrum regulation politics do not often provide stories for Hackaday readers, but this one should be of concern beyond the narrow bounds of amateur radio.

Most parts of the radio spectrum are shared between more than one user, and there is usually a primary occupant and a secondary one whose usage is dependent upon not interfering with other users. If you’ve used 435 MHz radio modems you will have encountered this, that’s a band shared with both radio amateurs and others including government users. While some countries have wider band limits, the two-meter band between 144 MHz and 146 MHz is allocated with primary status to radio amateurs worldwide, and it is this status that is placed under threat. The latest ARRL news is that there has been little opposition at the pan-European regulator CEPT level, which appears to be causing concern among the amateur radio community.

Why should this bother you? If you are a radio amateur it should be a grave concern that a band which has provided the “glue” for so many vital services over many decades might come under threat, and if you are not a radio amateur it should concern you that a commercial defence contractor in one country can so easily set in motion the degradation of a globally open resource governed by international treaties penned in your grandparents’ time. Amateur radio is a different regulatory being from the licence-free spectrum that we now depend upon for so many things, but the principle of it being a free resource to all its users remains the same. If you have an interest in retaining the spectrum you use wherever on the dial it may lie, we suggest you support your national amateur radio organisation in opposing this measure.

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Lucid Dreaming | Reality Check Moments

I don't think this site has one of these threads yet. So here it is.

The idea is to use the thread itself as a means to help with lucidity. As it has happened to me before. The thread is for posting about moments in waking life that happen to you that seems very strange and deserving of an RC. Well it can be something big, or something minor. It doesn't really matter. Something you see or happens that seems strange and tells you that maybe it's time to do an RC. Or maybe even just a dreamlike feeling... When that happens do the RC and also think about this thread with the intent to post about it.


With any luck, one of these times when you see something or something happens that reminds you of this thread and you want to post it here. You very well might be dreaming in that moment. So if you are posting in this thread and see something that makes you think of this thread. Don't forget to do the RC too...

But if you happen to think about this thread in a dream, and fail to do the RC and get lucid. Don't get down on yourself, it happens. It just makes the chances better the next time. Because you will probably remember the failure in the dream and want to make sure it doesn't happen again.

Good luck!

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