Listening Posts: An Intro to SIGINT 

The phone your're on is a listening and observation post

This may be the most underrated and highly important topic to date. Monitoring (listening) is far more important that transmitting.

"If it is not immediately convinient and effortless, people just will not do it." Legend

I got into radios in the 70s. Everything was opened then. We developed are own code/nomenclature so that we could talk on radios and nobody would know what we were talking about. We employed low tech ways to direction find. As time moved on , scanners became more common. I would spend hours listening. Tracking police, fire, EMS. Listening to aircraft over head. Cell calls. Public works etc etc. I gained a lot of information. Some have some pretty crazy back stories. Life took a different turn and I didn't have time for it anymore. But now I'm back at it. Bought a few new radios, along with vhf/ufh twoway for mobile ops. Considering a remote pirate repeater. Remember, the number one low tech listening device is your ears. People love to talk and they give you all types of free Intel. But that's called humint.

This might be useful for the software inclined: Write a program that runs on your laptop and monitors your frequency of interest as shown by your SDR, and simply record date, time of day, and length of transmissions. Do this for several weeks and you have a model of what "normal" looks like. Then use the model for comparison, and if current time window of transmissions for this time of day exceeds the norm by some measure, alert the user that something is going on.

Used to listen to LE, Fire and EMS frequencies in my area. Then the Sheriff's Dept went totally encrypted, and local LE did likewise. Now, there's nothing to listen except Fire and EMS, and they are now all digital. I think the public has a right to hear non sensitive transmissions.

New Daily SA and an S2 Underground, today is a good day!!

Like the old saying goes the best place to hide a leaf is in the forest. Sometimes standing out in plain sight is more concealing than trying to hide. For instance in an area that has a lot of homeless it might be more concealing to just blend in. Of course you'd have to really be careful not to get sick or stumble upon a dirty needle. 😬 Also you can dim screens or use veils to cover up screens.

A few weeks ago I heard an unusually large helicopter fly over my house so I went to ADSB exchange because they will show you birds with no callsigns. Well for 3 nights in a row they flew over my house under 500 feet to just south of the South Carolina boarder where I know there are large tracts of land that are empty. Well on the 2nd night at the same time I saw the no call sign bird flying towards my house so I went outside and it was a Chinook with an winch fitted. Fucker had to be flying around 300ft agl. The only reason ADSB exchange caught him is because there are a few people in our county who upload their SDRs.

On the southern border, we regularly (almost daily) use adsb exchange to monitor where BP and state police helicopters are chasing groups of IAs that are on foot. LE won’t take the time to give residents a heads up that they’re chasing a group of 20 people your direction, or through your backyard. But if you hear a helicopter, and it’s not too low, you can see where the people are.

I watched a search plane circle over my house on a flight app one night. A LEO had been shot and the bad guys got away, the command HQ was less than 100 feet from my home, but they had not searched around my house, where there are places to hide from thermal imaging. Sometimes relying too much on tech can be a problem.

oh man I wish more and more my grandfather had talked about what he did in ww2. from letters we found hidden in the house, he did radio stuff, smuggeling them from place to place, listening and communicating with London.

Many amateur radio operators (hams) enjoy fox hunts. Small radio transmitters are hidden and transmit for 20-60 seconds then go quiet for several minutes. Get a bearing then change your location to get another bearing. The fox is found within 1-2 hours. Sometimes within 30 minutes. During special events youngster 9-12 years are taught the basic principles and turned loose. So if you don’t want to be found, transmit your message as quickly as possible then move, move, move.

One of the most useful things I can think of that can help you make the most of your limited time is RECORDING. When combined with a scanning plan or a scheduler such as you’ll find featured in SDRPlay, these tools can help you distill hours of monitoring down to a fraction of that time in recorded material that you’ll have to listen to, and although it is less timely than listening live, it can still help you get a sense of longer-term activities going on around the listening post. Even better, with multichannel recording, you won’t miss a thing, because it will record simultaneous channels that you would miss if you had to monitor your targets in real time. Recording also allows you to log and review the communications as many times as you like, and heck, you might even be able to employ PC software to do a voice to text for you at some point, negating the need to have to listen to the recordings. The other nice thing about this automation is that you can set up any number of target or task-specific listening posts requiring different locations, antennas, etc. Set them up with a low-cost low power Raspberry Pi, well concealed, self-powered, and let them run unattended. I wish I had some programming skills because there is so much cool stuff that can be done, and unfortunately, many of the tools out there now fall short in one way or another, or are unreliable, cumbersome or simply lack the particular features one might need. Sure, this is next-level stuff I’m thinking about and probably only available to intelligence agencies, etc. But one can imagine the possibilities nonetheless. Imagine automating sensors, drones, cameras, radios, alert systems, etc etc. Cool stuff indeed. Edit: just after I wrote this I continued watching the rest of this video and you basically just said everything I just described in a couple of sentences. Great minds think alike. :)

Once again, the most important channel on RU-vid.

The tech prepped on RU-vid had a really great series on SDR’s. One thing he was doing is setting up remote monitoring on a chosen band/frequency. Then when he got back to his system they all played back while removing empty space because the recording was set up to be voice activated. The software maker he was using is planning on integrating that capability in a future build.

A good SDR can be run by a tiny Raspberry Pi3 or Pi4 with a small battery and a 20W folding solar panel. Man portable, small footprint, and an incredible SIGINT resource for perhaps $150. Some SDRs are not just recievers, but are transcievers. I have ponderd the possibility of engineering one that would give the complete functionality of SINCGARS (including crypto) but would be only slightly larger than a paperback book. This is doable, but is a nontrivial task. Another interesting and very useful device for intelligence gathering is a good frequency counter, especially when paired with a handheld Yagi antenna. The frequency counter is a special "dumb" reciever than only locks onto and literally "counts" or displays the transmitting frequency of anything transmitting nearby. These are superb at locating wireless listening devices (bugs) and the more expensive units with a hand held yagi can pinpoint the location of clandestine broadband networking routers. Going up in cost and logistics support would be something like a HP or Tektronix Spectrum Analyzer which with a good antenna can locate a clandestine drone operating even miles away from your OP/LP. Going further down that rabbit hole of money and resource expenditures you could add a full Microwave Generalized Signal Generator, a Microwave Power Amplifier (to boost the signal output to tens of watts) which when coupled with a spectrum analyzer gives you the ability to identify and jam or interfere with those signals. With such a suite of ($200K to $500K) you can have the basics of a legitimate electronic warfare setup. Playing electronic tag is not cheap by any means!

Steve Wallis is a great channel to watch for stealth camping. He's not a prepper or anything he just does it for fun, but you can get ideas.

An analog radio CAN STILL BE USEFUL. With a yagi antena, which can be built out of tape measure, tape and any cable in like an hour with no soldering at all you can take bearing of an intercepted comm. If they keep transmitting andthey are relatively static, and you can move 2-3 k you can get a new bearing. With that you plot in a map both LPs and bearing, and intersecting will be a rough area of where the transmission comes from. This can spot bivouacs, patrol bases, even covert bases with poor ish counter SIGINT protocols. With an analog radio, encrypted or otherwise undecipherable comms will turn in a spike of noise able to cut through your squelch. No need to listen in. Just by knowing someone transmitted you can locate them

Great rundown

Can't thank you enough for the time and effort that you put in to this. Is it so very much appreciated and shared often.

Always love your content and appreciate the comm based content. Thank you and keep it up.

4:24 & let's not forget about the sig int baloons up over every populated region harvesting everything.

Well… sounds like we need an extremely detailed SDR how-to video.

The 1962 Steve McQueen war movie “Hell is for Heroes” has a lot of SIGNIT and LP/OP major scenes where they make the Germans believe their squad is a battalion or larger size. They even make a hero sound like multiple different war machines such as tanks so the German LP’s report back the enemy has large support. It’s a great representation of some of the stuff you’re talking about and also a great movie. Stay safe!

Awesome video. Makes me want to spent a couple hours after work today setting up my SDR on a spare laptop or bring it to work and set it up better during down time.

Thanks! There’s a lot to consider in this video. Good stuff!

Really good stuff. Thanks so much S2. Keep 'em coming - We The People NEED this. Fight in the Shade.

Thanks for another very informative video.

Awesome info. Thanks for making this

Wow. All your videos have so many similar parallels to my obsession with communications. Very good production. 11/10

Love this freaking channel. Such detail

Good info. The background video is awesome---hiking through the mountains

A note: Some SDRs can use existing radio waves to act as a form of very simple radar. Edit: Passive radar.

Excellent presentation, very professional

Impressive presentation. Well done. Thank you.

For utilizing the ADS/B, traffic pattern recognition of normal civilian traffic might help; if the pattern changes for some reason, it MIGHT (and this a big might) be because the Government has requested the change so drones or other spy traffic can fly. There might be other indicators.

Having discipline it's one thing. But it's much easier to do when you're single and you don't have a family. When you need to help cook and clean also spending time with family is sometimes something that's not negotiable

This channel is a gold mine 👌🏻

I love this channel so much.

Excellent topics. Funny how the moment you stop talking about rifles, night vision and body armor that the audience thins considerably.

Damn right listen way more!! I would NOT immediately PTT & Tx on radios of any kind to get “help”, there won't be any. Just folks looking to take what you have. Rely only on those you already know in your circle, etc. Instead I'd use a scanner to listen to what the outside world is doing and what's happening - all in 1 handy radio to monitor it all. I have all bands/channels & active frequencies in my area programmed now. I also use the 'signal stalker' feature on another scanner to pick up 'danger close' radios & personnel, ie, those that may encroach my farm fence lines. I don’t use Ham radio etc, to talk to pple 200 miles away; it’s pointless, they can’t help…can you help them? Nope! Do I have CB, FRS, GMRS, MURS, 2M, 70cm, marine VHF transceivers, etc? Sure! I’ll Tx on them IF I really, really, REALLY need to com outside the family, but only as a last resort. To talk to family all over the ranch when SHTF, we're considering a part of the HF band no one uses, so no one is listening either. We're looking at HF radios built for .5W to 2W ERP with off-channel freq's. All the usual CB, FRS, GMRS or MURS, etc, is like waving a white flag at your front door! Imho.... comments??

Another great video!!! Well done.

Love your posts, keep up the great work

Outstanding content...yet again.

Being a dude with a background so far from this, you couldn't detect it, it's amazing to learn so much on your channel.

Thanks once again

This is awesome......... good refresher and knowledge. Alot people in tactical community think weapons, armor, tactical kit but overlook surveillance and information/intel gathering a lot dynamics and complex methods to make an operation go.

Extremely useful content

This was really interesting and useful. Thanks!

This is all so fascinating to me. Just starting to get into radio and don't even have a license yet but like you said. baby steps. I like messing with online SDRs and listening to the number stations lol. its just fun. Pretty sure I live near a DOD listening post. We have one of the massive VLBA antennas here and right above that on a plateau is a massive 80+ antenna array. DOD says it is for "mission critical DOD and important mission air traffic control". think it's called the Brewster Teleport.

An interesting video full of good information, but I feel in your focus on the direct operational application of SDR you undersold some of the additional benefits of an SDR which in all kinds SHTF situations can be really beneficial. That's is that it can pick up such a wide range of traffic, not just the usual hand held coms or overhead aircraft. It's ability to also pick up traffic from overhead satellites so you can get independent weather imagery is great. Knowing if that storm system is moving on or coming your way can be highly useful. Picking up long range radio channels so you can hear independent news from other countries much like resistance fighters did listening to BBC world service during nazi occupation. Listening to HAM radio bands for information on the larger picture etc. All of that can be done without emissions too, just receiving. Keeping your immediate area under surveillance for situational awareness is important, but looking longer term for a way out of your situation you need to also know the bigger picture and SDR gives you a range of options there

great video, thanks for your constant effort

Love all the b roll footage taken from the 35T recruiting video

SDR's are my achilles heal. I don't make much money a month, only my 20% VA disability, so when I say in my world, I've spent a small fortune on different sdr's and antennas trying to get them to work. I've tried different sdr's, different antenna's, different software packages, and just can't get them to work. The only frequency that I could get it to come in is (I believe it was 128.000mhz) I couldn't get the sdr to scroll up or down the frequencies. Which is a bummer because I find it very fascinating.

Another awesome video S2. On the off chance that your team hasn't come across it yet, the kerbos/kraken sdr is a fantastic RDF tool.

very interesting topic..... we have a couple of folks who listen to scanners a large part of time... listening to police and fire operations leads to a bunch of information like the puma that was sited by LE this last weekend IN TOWN again... a couple of years ago one was caught and relocated and over the last 5 years several have been sighted. 4 years ago we heard [and went out to see] a black bear across the street from us IN TOWN.... a lot of things never make it into the news media.... keep up the good work!!!

Also keep a spair USB drive and OTG cable. The USB will have Phone and PC back up software incase you need to ditch the interface device (phone/PC) and replace it later.

Some Androids apps new folks might find useful: Ham Solar: find out if the sun is grumpy today. Gives you the listening conditions for shortwave and ham bands. Ham Bands: color chart showing where hams hang out and what modes are used in a particular. But you can listen in just about anywhere. Don't considers band plans as limiting for RX. Skywave Schedules: Frequency Database for SWL and "utility" stations, and logbook. (I liked this one enough to buy the upgrade.) NCDXF Beacon: worldwide beacon system that lets you chack band conditions. Useful, educational (compare against Ham Solar), and wildly entertaining if your a comms geek. DroidNavTex: Decode maritime weather. Costs money. HF WeatherFax: Weather maps Amateur Radio Toolkit: a bit of everything Antenna Theory: Buckle up, Dorothy. Day&Night Map: Just what says. Dipole Antenna Calculator: ditto Helical Antennas: likewise. Signal ID: purportedly identifies digital signals. I'm still working on it.

Thank you 😊

OMG! The # 1 thing that im told by the family is how can you just sit there for hours listening to all that static...But with a few adjustment to the volume and stepping the levels that they are set makes it easy for me. i can usually catch traffic just by the way the static sounds. My wife has been more than once amazed that what starts out as just static turns into traffic . Anyway ive always enjoyed listening and yes i do talk too but i tend to listen more than talk. I think that some people cant stand the sounds that come over the radios and quickly move on but i guess im lucky i have sharp ears. So if i could get paid to sit and listen all day that would be a dream job LOL. serious Dream Job.. well moving along love the video as always well presented. Thanks so much.

23:27 “we’re not going to be embracing the suck because some NCO told us to” Yeah, that’s why I embrace the suck on my own accord, ie running, listening to radio chatter while I cook and clean, learn when I can… I mean FFS, I’m listening to this at 0119 because sleep insomnia, might as well make it (the suck) useful.

Great video, I need so much help with this and the topics that surround it.

something I would like you to touch on is security through obsolescence.

Loved this subject. Was S-6 for a few years.

I think the most valuable listening post for an individual would be to monitor what's happening around their house. For instance, using an SDR to monitor the number of mobile devices (radios, cell phones, etc.) proximate to their home, and potentially even using two or three for some rudimentary direction and range finding. Ideally it would attempt to fingerprint the collected signals and record those fingerprints into a database. Is an unfamiliar device scoping the neighborhood? Maybe you should save your surveillance video from that night in case they were exploring without a cover or disguise to help identify them in the future. Or perhaps if they return you can set an alarm and maybe catch them in the act. Are there multiple unfamiliar devices staged near your house? This could be the Stasi getting ready to kick your door down, or it could be a multiple-assailant burglary. I keep poking around at the idea but then life comes up and I work on other projects.

23:08 despite this I adore your radio and sigint stuff.

i love how s2 uses comedic irony. this guy is COOL in my book.

Excellent topic. During the riots the participants used PTT Apps to communicate. They had another individual who set himself out of jurisdiction and established a LP . This individual monitored the non crypto interop talkgroups that were being used and relayed info to the on site participants over the PTT app. This LP individual in his "down time" compromised himself by generating malicious interference to businesses in the area he established his LP at. Movement to a crypto talkgroup ended the riot within less than 24 hours. Thanks for sharing !

Thank you.

I just stumbled upon this by accident and I know nothing about radio communications haha.. This has me thinking.. Thank you.

Love your videos man

The biggest issue now, especially for police monitoring, is that they are encrypting their radio systems and they are using 256 bit encryption to do it.

Adding chokes to power cords of utilities, tv’s and computers can drastically quiet the rf noise levels in your home. You can use your SDR by shutting down all curcuit breakers in your home and checking your noise floor for offending devices. It takes a bit of work up front, but it can drastically lower the noise floor in your home, making couch sigint gathering possible.

7:23 Can you do a build video of your hand held ADSB?

22:58 "I understand radios arent exciting" buuuuullllshit. Radios are fucking awesome. I've willingly sat and listened to 3 hours of blank radio noise or data transmissions on websdr just because it was there. Im starting to get into HAM myself love that you're covering radios and signals intelligence and can't wait to see what else you put out.

Add a directional antenna to the pack, need to know where the comms are coming from. Even if encrypted, can still monitor the simplex or input frequencies to get a direction and signal strength.

Spot on

you guys have all the goodies, i am very much envious. also I'd love to see a video on Drone/UAV usage for the individual/small team, specifically related to Surveillance and recon

Love the work S2, keep that powder dry & these great vids commin!

You should do an updated "First Steps" video 📹 with suggested gear ⚙️. Basically, for people like me who are new to all of this but want to have fun 👍 building a good kit.

I'll have to dig up my old scanner that I bought decades ago when I used to have a radio at work and change the channel to listen to the emergency traffic instead. I found it so interesting that I bought my own scanner back when it wasn't that expensive.

soaking this up like a sponge. you are awesome at detail without boring to death. thank you.

your presentations are spot on, comprehensive and educational platforms. soup to nuts. S2 underground is a go to source with quality and balanced material. bravo & kudos.. continued success. achilles

Ex Army SIGINT here. You're pretty spot on.

Good stuff!

I learned a lot here ... thank you. If only I knew more before I chose my MOS

Your topic is very well presented. I have not read the comments, and I know this is an intro but I would also mention a SW capable receiver and or AM/FM and NOAA capable. 73

LP/OP is my IPhone 😆 time to go old school and wire up some Dixie cups. Great video and information

First step is make a baseline of known emmissions, compare against the unknown results in a smaller amount to resolve.. Baselines take time and expertise and are sometimes shared between agencies/teams. There is an internet project somewhere which encourages SDR users to collaborate worldwide with spectrum grabs over a period of time.

For the tidbit on 'Hearing your surroundings', ENC, or electronic noise canceling, also works in reverse. You see this with most operator radio comms headsets. It will dampen sounds of certain Dbs, and increase volume of lower Dbs while maintaining that level of normal hearing.

You have no idea what they can do with your phone NOW. My niece was missing for two weeks so we went to file the report. They were able to locate her phone, he said it was turned off. A few mouse clicks and we could hear EVERYTHING in the room her phone was in. A few more clicks and we could see from her iphone, it was just the ceiling, he then turned her phone on remotely and sent her a message saying her family was looking for her and missed her very much. He then says there was another device nearby, he ID'd the owner and sent him a text saying she was only 14 and the police were now involved. Within 15 mins he kicked her out of his car in front of her house then peeled out! I wouldn't believe it if I hadn't seen it. It was awesome and scary at the same time.

Note on the scanner part: we had a benchtop EMS scanner unit. Cost about 50 bucks, but if you opened it, the whole thing was a bit bigger than a playing card, inside a box the size of a game console, and it ran on a 9V wall adapter. Easy enough to shrink the case, and run it through earbuds.

Amateur radio leads you to this naturally, if you have a curious mind. Pretty soon you're tracking planes, hams, seeing all the signals flying around, and tracking them. Also helps you to navigate Part15 where that still makes sense. I often hear aircraft from inside my home and want to know why. Sometimes I see planes or hear planes on cameras and have found there is no telemetry (at least not at 1090mhz). In my opinion, we have to track ALL THE THINGS because someday soon there will be zillions of hostile unmanned craft orchestrating our death. Read the book _Kill Decision_ by Daniel Suarez if you haven't. It'll get you thinking. Great video, btw, learned a few terms.

North of a town I used to live in 50 years ago there was a listening post out in a farmers field on the top of a ridge. It was a small empty concrete room with wires cut off coming out of the concrete walls. Unsure of the age but could have been a WW2/Korean conflict or Cold War post.

This guy I know had a polished satellite dish in his back yard. It was maybe 4 to 5 feet in diameter and he to keep it covered at all times. If angled appropriately with the sun it could light 2x4s on fire by waving them in front of it. You could also use it to listen to neighbors conversations across the street AND talk back! It would sound like a disembodied voice was whispering in your ear.

I just discovered your channel yesterday and so far you have great content! I attended one of Brush Beater's courses years ago in Montana and followed him for a long time, even before American Partisan existed. Anyway, where did you get that metal enclosure for the HackRF? I only see crappy looking plastics ones out there.

some SIGINT gear i find useful are the "DopeScope from warcollar industries which is really just a handheld, standalone directional wifi scanner. it's handy for both active and passively scanning wifi signals to find a phone or base station. the other two from HAK5 are the WiFi pineapple which can also serve as a wifi for when you don't want to be right next to your sensors or you can use it with a cell phone or laptop to listen to wifi transmissions. the other from that vendor is the SIGOwl which when used with a computer or cellphone lets you hook up and manage multiple SDR's and automate them slightly. after all if you can get close enough to a threat to collect PCAPs from them, you have a wealth of intel. especially when so many common apps transmit valuable data in cleartext.

In the simplest form, I guess you could call us a listening post, but, we prefer the term intercept site because SIGINT (both ELINT & COMINT) is quite different and requires totally different skills than the combat arms listening post. For example you mention getting an LOB and reporting it and the freq, if you have abilities in the target language, a callsign is extremely beneficial. You are right about intercept sites being a target / artillery magnet - the AN/FLR-9 at Field Station Augsburg (Germany) was lovingly referred to as a SCUD target. Yes, we never shared technical data with the operational commander, although we did report the intelligence derived from intercept.

For a inexpensive analog "scanner", the Wouxun KG-UV9 series of radios have a great wideband receiver that includes aviation AM receive. There are models that transmit on the amateur (ham radio) bands and there are models that transmit on GMRS. They have good superheterodyne receivers, 999 memory locations, and can be purchased for under $200.