SHTF Intro To Radio Direction Finder "Seek & Destroy" Part 1 

We did this in Afghanistan with Japanese ICOM radios and some slash wire wrapped around a small x-mas tree shaped piece of plywood. We would get azimuths from two locations and do a resection on a map to find taliban... looked janky but it worked. We weren't even comm, just a bunch of dumb grunts with radios and imagination.

My job in the Army involved a similar process. We would find a signal and network two other stations, each would shoot a LOB (line of bearing). We'd plot it on a map. Two LOBs give you a "cut" at the point where they cross accurate to roughly a grid square. Three LOBs gives you a "fix" accurate to 10' or less. You then give that resulting grid coordinate to the Gun Bunnies and they will drop steel on it! HOOAH!!

Lol. To go right down hill from this. I remember years ago a friend on CB radio would not believe he could be found by RF tracking so we had a £10 bet that I could find him. He was just a CB friend and he lived somewhere in my big city but I had never been to his house so I had no idea where. Getting another friend to drive me, we first drove in a slow circle of my neighbourhood to ascertain the direction of his signal by watching the CB signal meter. (We were using an ordinary mag mount antenna on the roof of the car so no high gain directional antenna like a Yagi) Once we had the rough direction, we set off across the city and watched as the power of his transmission signal got stronger. When we had his signal peeking out the signal meter on the CB I disconnected the antenna lead and stuck my finger in the antenna socket. The signal strength dropped by half so we commenced another slow circular drive around until the signal meter showed the highest reading and set off in that direction. When the meter peeked again with my finger in the socket (I should add for any idiots reading this: NEVER transmit on a radio with your finger in the antenna socket, even at low wattage, if you want to keep your radio intact and at high wattage, your finger intact.) I got out of the car and checked the roofs for CB antennas and his was the only one in the immediate area. The look on John's face when I knocked on his door was priceless.

Fantastic video! Love it! Please keep 'em coming, can't wait for part 2. "Backblast area all clear!" =)

Frequency jamming is a hobby of some people. The tricks are to use short burts at random times. Transmit long enough to cause the equpiment to be disabled then it will take some time for it to come back on line. Thats when another burst is sent. Although don't transmit exactly when this happens because the people searching will find out the pattern. Some things don't have to be constantly jammed to become compromised. Yo just need to be able to make it unreliable enough to cause problems. Another trick is to never directly transmit towards your target. This makes you very easy to find. Better to use more power and reflect the signal of the terrain towards the target. Multipath propagation that is a problem for transmitters can be taken advantage of to place your transmitter within one of the "nodes" to make the signal look like its comming from a certain direction but really its bouncing off a hill or a building. You can also shift the frequency around to throw off trackers. Purposely transmit on frequencies that don't cause jamming to make it look like a malfunctioning equipment. Not just any frequency but ones that commercial equipment would actually use if not configured right. Also verying the power will make the signal look like its father away or closer then it really is. You can use this to mask the location: maybe at a certain power the signal will bounce off a hill but at a lower power it will appear to coming from the opposite direction. The use of yagi antennas with lots of directors is key to focusing the beam. Also remember your equipment is going to give off an IF signal that can make even receivers detectable. You can create phantom IF signals by finding out what common electronics use and set up slightly higher power putting your signal below the noise floor. There are tools in linux radio programs to make all kinds of signals or you can even just record a signal clean it up and re-transmit it making it look like a valid peice of equipment. The limit is your creativity and with enough planning and knowledge you can minimize being detected and enjoy many hours of this hobby.

Very interesting to watch. I'm a ham, and am familiar with the concept, but have never seen it put into actual use. I'm surprised you did it alone. But you were able to find it. Good for you!

Very interesting, looking forward to part 2, thanks for sharing.

Hope you find him. We used to play radio tag with our CB radios back in high school. This brings back some great memories of parking in the creek with a camo cargo net draped over the truck.

Im just getting in to ham radio and direction finding and encomm are the most interesting aspects, imo. Great video. Thanks

Hi GCom - I'm loving the video - searched eagerly for Part 2 - not on line yet! Aaaargh! Here a couple of points I wanted to make: - Sometimes it's more precise to locate the azimuth of the nulls than the azimuth of the strongest signal (eg. when the antenna is not highly directional) - just remember to correct for the +/-90° offset. - Moving to your next DF point is best to a location on a line at right angles from your last azimuth reading (eg. when your last signal azimuth was northeast then drive some miles to a location southeast or northwest for the next reading). This maximizes the chances of a larger intersection angle of the azimuths and minimizes the area to be searched, Once you have two azimuths you can better choose the location for your third reading. Aim to get a large angle of intersection with the other azimuths. - Use a prismatic or lensatic sighting compass to reduce errors in reading azimuth. Remember compasses can be affected by magnetic metal objects eg. cars, radio loudspeakers, guns, power lines, pylons etc. ("deviation") Remember too that north error ("magnetic variation") may be strong in your part of the world and compensate for this. - If you can use a GPS to locate your current position (by smartphone, car or handheld GPS) you can plot the bearing more accurately. But remember GPS is affected by number of visible satellites and multipath. Hope this wasn't teaching Grandma to suck eggs :-) I'm eagerly awaiting Part2! Well done, all the best, Rob

really cool video, can't wait until the second half!

Back in High School when CB radios was a hit we used to play Fox Hunting. it was a lot of fun.

Love it, you use similar processes to myself. I need to get a beam like yours though my 13el or whatever it is is too big for the car and tracking really :( but works. I usually start at home with the portable (usually Moto XTS with ear tube) and pan around in vertical then flip to horizontal to lock onto where I think they are (seems to drop the signal if I'm wrong which is rare). Then drive time. I never really went with mapping software more location triangulation and local knowledge. It's good to see others using similar methods but I could not use anything other than another radio to track :(. It's ironic seeing this actually as when I approached Simoco for P25 upgrade pricing I was met with the bs argument of "we won't provide it because you could interfere with emergency services". My great reply was along the lines of "I don't need P25 for DoS! A few FM828's (OLD crystal radios commonly used in repeaters) into yagis with the right crystal and 100% tx with cooling will VERY quickly knock whoever off their network". Their higher ups seemed to agree with me that their argument was stupid and supplied the pricing. You would have to be careful around here though on the cops, I'm not sure what they are using but I've heard them reply to cars asking about where a car in trouble was and they were able to reply with "the last signal came approximately x km's from the tower on xyz at x degrees mapping around abc position".

Awesome stuff. Very interesting!

Good video, back when I fox hunted for fun, I'd also have a telescopic antenna set up that I could reduce in length as I got closer, then switch to a wave guide to close in on the target. (Just a short stubby antenna mounted in a coffee can with a wooden handle.) It's interesting to talk to a drunk CBer with just an old toy CB radio walkie talkie that used a 9 volt battery and only put out a few milliwatts of output and you'd be the only one he could hear .

Interesting technique with the single man triangulation. Never seen that one before.

Horizontal polarization (16:50-17:23) is extremely inefficient with ground wave propagation. Especially since everything you were receiving from had a vertical antenna. In only rare cases, it can help to tilt it during triangulation. Just wanted to make sure you knew. Nice video, though.

Something I've been playing with lately is SDRs. The $8 dongles are certainly useful, but there are a couple that are built on dongles on ebay that have some of the mods that make them better already done ($40-$60, which is pretty cheap relatively speaking, considering upconverters alone cost $50 and up), and include an upconverter for HF. They will work with android, so you could use one for this application as well have maps all in one device (electronic mapping is great isn't it?). Even better would be the hackrf or bladerf, etc (you can spend as low as $8 for an SDR upwards of $1000s). The one guy uses a hackRF that he has made a very sophisticated fox hunter from, that you might be interested. He has done many vids on youtube, just look for something like all you freqs belong to us or hackrf, the guy is from Australia (now in the US), so you will know when you find him.

Great video you know your stuff man...

Do you know what gear id good to be used in 25ghz signal finding? ..Things are developing so fast that i need advance and upgrade.

Did you purchase or make the directional antenna?

Very interesting video ! ! Thank you ! !

Do all uhf and two way radios always give off that static or only when the call button is pressed?

What model Yagi do you use or prefer? Is a single or a dual band?

im confused on where to set squelch. do you want to set it where you hear squelch or just past it to where its silent?? great vid

When you find him call in some artillery fire........LOL

3 element Yagi has main sensitivity lobe of 30 degrees. It is better to use small loop antenna for transmitter hunting - even on VHF, because loop antenna has 2-3 degree very deep sensitivity minimum which gaves better bearings and moreover it is easier to search for minimum of signal when the signal becomes really strong in the final stages of searching.

Hey Brother, love your videos. I was born and raised in Cali, your videos make me homesick. I was wondering if you wouldn't mind sharing where you were at in this video?

Really good information. Have you tried using the RTL-SDR dongles? It's a very cheap solution that offers a 3.8 megahertz bandwidth. And only for $20 or so you can connect it to your Android device or any sort of smartphone. So no need for generators to do is connect your directional antenna to the dongle and do your work with your smartphone. You can even have it sync up the strongest signal received on your target frequency with the gyroscope in the phone to pinpoint the heading and do all the calculations for you. Another advantage is that you're able to see large spreads of frequencies so as the frequency shift you can see it in the waterfall and you will still be able to track it. 73's KC3EOL

Haha just like how I was taught to track wildlife with RF necklaces. Squeltch is ur friend for that.

He should have recruited some ham radio operators!

Is this kelowna or kamloops? could swear I've seen that area somewhere before...:)

much respect

I am studying right now to get my Technician Ham license. This video brings back good memories of Fox Hunting. Where can I get one of those directional antennas. I am thinking about getting the Yeasu VX-8 FM Triple band handheld. Is that a good handheld.

A yagi and an attenuator is all of the gear you need to find the fox. Triangulation works well. In close a doppler system works super. You need to get a tripod for that yagi. Laying it on the ground is not real good.

All ways stand away from radio/antenna. To make long distance fixes. Why? Every degree translates to a lot of area. And the term is called triangulation. A map vs a set of readings. And crossing lines on your map give your location . Good hunting practice. Tks for good show. Kv4li

once you got a few high elevation bearings i think you were waiting time after that by not going to the bearing cross. even with 1 bearing you can get some ideas where the transmitter might be. get on it.....

Ww2 German operators would pinpoint radios by RDF. on the radios(in prison camps) local oscillators. Found by triangulation. So it's not a new thing. Though very useful.

What's the strongest repeater made?

this system of finding a signal won't work if the person was to move around transmitting the signal. these ham guys would be scratching the heads, also very it by a few KC's or a slider then it really gets hard.

A little bit longer than it needed to be, but still a great video showing and introduction into these techniques and concepts. Hopefully, more people will see this and realize that allowing their kids to "play" on a 2 way radio is not only illegal, it's extremely dangerous. Hey, is that a Yaesu?? :D It is modified? ;D You should do a video on that alone!

It looked to me like you were over thought this. Had you done an intersection on your map you would have a general idea of where the signal was coming from. Using a military style protractor, or ruler, you could draw out the line from position 1, at position 2, draw another set of lines based on the point where you get the strongest signal. with a minimum of two lines you can now see the point where they intersect. Where they intersect is where your signal originates.

Great info. I love this stuff. What would be the purpose of needing to find the malfunctioning source? I know this is a demo but I would figure there would be some sort of visual read out of all the transmitters.

Except for the.....NOISE (music) I liked your video.

What about a RTL SDR with yagi and mobile ????

You can get an RTL-SDR key, attach the Yagi antenna to it and connect the RTL-SDR to an Android smartphone/tablet and have a super portale spectrum analyzer able to scan from a few Mhz to a few Ghz. The software will also let you listen to the signal as you do with your Yeasu. You can do WFM, FM, AM as well as SSB. A cheap but incredibly useful and flexible setup ;) If you like then you can get some more "professional" SDR with better sensibility and even wider range.

fox hunting , every weekend, lol, beware of the fox bouncing the signal off buildings LOL!

Do you offer services?

How does a radio signal travel from person A to person B?

Cartels in Mexico use this to fish out rival cartels. I’d imagine if you were smart enough you could use this to set a trap and lure the radio hunters into your kill zone. Seems almost to easy to lure them in.

Sometimes you just down right funny --- sometimes not so.

There is directional software

where is the map?

Were you compensated I hope.

3:52, he finally stops flapping his gums and starts doing something.

This guy refuses to even say the word "B**feng" lol

Where do I get one of those bar graph spectrum analyzer things? I'm having trouble finding my backlash area.

Avoid detection..= Move.. Short transmission.. Adjust transmission time's.. Every 5 hour's, now ever 4 hour's .. Lag time for respond.. as well as Chang frequency.. Never broadcast FROM home..or base camp..

A yagi is a very poor choice for a DF antenna. A few observations 1st It's much more effective to use the deep nulls off the bak of the antenna rather than primary gain lobe. Here's why, The maximum gain and 3db bandwidth of that small yagi primary lobe is not nearly as high or as sharp as the deep nulls of the back sides of the antenna . The yagi might have 3db or so forward gain with a whopping 60 degree 3db beamwidth . On the other hand the nulls can be down a whopping -20+db with a beamwidth of less than 10deg and there will be two nulls on either side of the back of the antenna. hands down the best antenna for DFing is the small mag loop. Mag loops have very sharp, deep nulls so instead of peaking the signal in the primary lobe you null it using the nulls of the back of the antenna.

Its new

You need to start your videos with less intrusive music.

I got to skip this video cause to much talking and saying the same thing over and over again. Hope part 2 has more action and less talking

Repetative as could be... each time you stopped in a new location, you said the same exact things, but each time it took 5 more minutes than the last- coulda been a 4 minute video in total, and there's a part two to this? Must like hearing yourself talk

Okay, if the Sheriff's repeater is really being jammed and you've really been asked to help, why don't you shut up and get at it? In all honesty, your RDF technique is crude and ineffective. Almost nobody uses triangulation anymore. Radios and antennas have gotten sophisticated enough to allow you to just follow the signal direction to a small area (a city block or less), after which you use common sense (where could the transmitter & antenna actually be within that small area) to find the source.

"Seek and Destroy"? Somebody has been playing way too many combat video games. LOL SMH

Gosh :-) you talk too much and show too little :-) . Why can't we see the progress on the map where you plot the directions. You mention taking a compass bearing - Would be really interesting to see where the first set of lines cross, and how far the estimated position of the transmitter move as you refine the solution.