RDF Write Up

Michael Chisena ka2zev at yahoo.com
Tue Jun 10 11:09:35 CDT 2008

Hi all,
I don’t have a huge amount of spare time today to put a shine on what is a number of e mail exchanges. 
This morning June 10th on the 146.79 we were talking about RDF and some issues related to it. This is a follow up I agreed to after that chat. This data might be useful for others who want to learn what I call 'the black art'.
Might go into detail on the Tech Net tonight 53.61 and 442.100 at 20:00.
It’s no secret that I’m indirectly involved with RDF efforts in the area. 
As a community, we seem to have collected some new and exciting idiots.
Repeater jammers come in several flavors. 
I caught a fair number of stuck transmitters and four jammers. 
Three behaved after getting my notice, number four was a psycho.
Some are simply accidental. 
These are guys who for some combination of technical reasons end up hanging a carrier on a frequency, and not noticing the fact. They can be found, talked politely to and in almost all cases shut off the transmitter and apologize for being a nuisance. 
Finding signals like that is about as difficult as locating a cue ball on a pool table. 
It just takes work.
The next class is also fairly straight forward to find. 
It’s been my experience what causes repeater jamming is weak willed individuals with a grudge. As techie types, we tend to forget that everybody else has a ‘human side’. 
We live with our likes and dislikes. Praises and slights. If your lucky they can be intimidated into behaving.
The bigger argument is ‘what is normal’? 
There is no one size fits all answer for that question. 
Yet it’s clear that some people can be driven off the fine edge of control if they are not happy and entertained.
With radio it’s easy to ‘ruin’ someone’s day. 
Just push a button. 
From my perspective, this is a failure of moral character.
So the larger part of direction finding is figuring out who is unhappy with whom. 
That cuts down the field of suspects by about 99%. 
When it comes to efforts like this, some information can be ‘public’ and a good chunk has to be ‘back channel’. 
We live in a socicity where if people feel ‘wronged’ for any reason, lawyers get involved. And the price goes up from there.
Accusations are bad, making a wrong accusation or not having enough evidence is a huge error we can’t recover from.
Ive done DF work in New York, and had to hold back on opinions until the facts were in. This restraint has done me well. Make sure, make real sure. Never trust a random sample of ‘one’ on any RDF mission. Get someone else to see and hear the same thing.
Found my share of stuck transmitters, real repeater jammers, and some strange interference.
The last and hardest to figure out class of repeater jammer is the Psycho. 
I’ve met a few. 
These are people who don’t care about the rest of us, they are going to have their fun, or make life difficult for the rest of us. 
Fortunately these guys are fairly rare, but they do not respond to anything but enforcement. Even that’s hit or miss.
Give this a thought for a moment.
Let’s say as individuals we build equipment and learn how to use it. 
Using all this stuff you actually find someone doing illegal things on club repeaters. 
Just what are you going to do about it? 
In case you hadn’t noticed, I don’t carry a badge, never took an oath. 
I’m just another citizen with a pile of weird gear in their vehicle. 
I don’t have any magic enforcement powers. 
I have no method of forcing compliance.
Ham radio is in many ways an anonymous hobby. 
We live our lives behind keys and microphones. 
Only venture out and socialize on rare occasion. 
Ours is not a spectator sport. It’s a private activity. When the spot light is shined during our operation we tend to blink and stall out a bit.
RDF is that spotlight. 
When I find jammers I play some nasty head games, let them know in a fail proof way that they have been found, that I know who they are, and if they want to stay in the larger social group, sin no more, or be black balled. 
Coming from an Old Line Italian family, we call it Black Mail. 
It’s the only lever I have when jokers are found, so I pull it.
In DF you need to think three or more steps ahead in the process. 
In the end you know your going to find someone. 
The critical thing is to have a plan on what to do after they have been caught in the act. Humans don’t like to be forced to deal with their unpleasant behavior. 
Remember its one thing to catch a tiger; the trick is to have a plan for what comes next.
RDF is a black art.  
It’s not going to make you popular. 
In fact the rest of the community looks at guys like me with a skewed sense of dread. 
Who has never made an error, who has never had a spike of anger? 
With guys like me around, nobody is completely comfortable.  
As in whom am I going to catch next?
Similar to finding out that your nice quiet neighbor was also the state executioner. 
How do you make small talk with someone like that?
What are below are some snips and adjustments of e mails back and forth with various people involved in the RDF effort in the Northern Virginia area. 
Read the notes, click the links. 
Names and styles have been altered.
I’m going to inject some comments and further insights.
Build some gear, practice with it. 
You too can get funny looks from concerned citizens.
Keep it warm
Mike aka KA2ZEV
Control Op X and I had a chat.
You got some weird people on channel.
I see two things happening here.
One is a public threat that most of these idiots don't respond well to, 
and the other is a private back channel that will work if careful attention to OPSEC (Operational Security) is maintained.
{Guess I need to ‘break this out a bit.
Public Threat. 
Is the kind of chatter along the lines of “Hope like heck I don’t find you first, blah, blah, blah”. Such trash talk did not work in grade school, now that we are older and more experienced why do we think it’s going to work now? Come on, get real.
Catching repeater jammers means we must stay on the moral high ground, no matter how ugly the jammer gets. We must do everything right, no matter the provocation.
Most repeater jammers are cheap bullies, they know what talk is and they know what’s real. Talk is a goad; it makes them do their thing more. 
Sometimes this is handy to have a ‘goad’ out there keeping the bozo on the air. For the most part it’s just annoying that I have to hear the bozo and the goad ‘go at it’.}
You know your audience, and I don't. I'm willing to watch and learn.
{This is my acknowledgment that in this case the repeater trustees know who their target is and that I don’t. In this situation my roll is simply back seat driving. I’m watching this play out from a distance and not taking part.}
If you want to play a head game...
{Some of the most effective ‘anti jam’ we have is PSYWAR or psylogical warfare. 
Back in New York I got to be a known player. 
If I showed up on a channel where there was a problem, that problem got worse. 
Because my location was known. People were afraid of me and what I do.
Did some follow up head games with dual band radios to make it sound like I was home while I was someplace else.  
I used to go DF hunting in awful weather. Once in a hail storm. Got real close that night.
It’s fun to mess with peoples heads. 
Conflict with other humans is not about ‘playing fair’ it’s about winning, because winning is the only thing that matters. 
In anti jammer efforts, there is no joy in second place.}
Shoot me a (text) message on the phone to 'disappear' (text) and mention on the repeater that I'm out and about. See what happens.
(Used to do this back in New York, guess what, my reputation was such that people didn’t fool with the club assets if my location was not known.)
That's why I suggested to Control Op X to look up a PsiWar expert for ideas.
We can play the head game back.
I also think making people’s phone ring at the wrong time can have an effect.
{This is one of the better ways of catching someone. 
Open microphones catch a great deal of useful data. 
Phones, other radios, environmental noise, each one of us has a unique background to our transmissions. 
A useful tip to hearing all that is to loose the factory speaker in your hand held or mobile. Between the mechanics of the speaker and the resonances of the housing, factory speakers are good enough for voice.
Put a good ‘hi fi’ speaker on your radio. 
FM is a high fidelity medium; you will be astonished to hear all kinds of new things. Those ‘things’ can be telling.}

RDF Stuff
{There are guys who have beams, maps and all that wonderful stuff, it works, but the problem is it’s slow. It’s nearly useless for nailing down ‘fast kerchunkers’ and other types of quick signals. 
The weapon of choice for my style of RDF is a Doppler Direction finder. 
Not much beats it, and in this forum I ain’t going to say how to do so.
Give you a hint, I used to practice on packet stations, and that was plenty of time to get a reading.
The down side of Doppler gear is poor range and a high noise floor; I need a good steer into a general area, after that I can engage. 
So a good hunt is a group effort. 
The beam people tell me the general area, and I get to find the source.}
The problem is, factory built RDF is expensive.
These guys don't publish a price list.
Some "Marine" RDF is adaptable but the antennas tend to be huge. 
I will check out some of it and report back to you. 
{I failed to find any new Marine RDF units at a rational price. 
At one time Apelco’s and Regency’s were common and worked just fine. 
None seem to be listed on web sites or stores. 
Got to wonder about this. Will keep looking}
Rule of thumb, if it picks up EPIRBS (121.5MHz ) then it will work on 2m.
At our level most RDF tends to be kit made and this requires a lot of thinking. 
Then learning to use it takes even more time and money. 
Most everything you learn about real world RDF is the opposite of what common sense tells us.
With that said, here are some links.
Give this one a read in detail, buy the book
{This book is amazing. Lots of good and useful data in it.}
This is the unit I have with some highly non standard mods to it. 
Stuff never thought about in the book.http://www.homingin.com/DSEfix.html
I'm fixing up the 'sense head' for my Doppler unit.
Next week when that's finished I need to look at the analyzer unit, get a fresh battery and see about punching some holes in the roof of the truck. I can afford to operate that, 
I can't afford too many more RDF trips in the police pack!
{Skool Daze. 
There are no training classes for this stuff. 
Ever heard of a university class that teaches people how to make ham repeaters?
Same for RDF. 
Most of it is self taught and the lessons are all expensive. 
What I can do is have a sit down with people interested in the issue, show and demo some goods and explain how some of this stuff came to be. 
There is no reason to be stingy with the data. 
If I can flatten out someone else’s learning curve, why not. 
What I won’t do is converse about the subject with a suspect. 
When you learn the technology, you also learn its weakness and how to defeat some of them. Life is tough; it’s harder when you hand your play book to the enemy. 
I ain’t doing that.}
We should hang out and chat about this issue some time.
Bring a note book; the data dump will be extreme.
When I teach people how to do DF I also teach people how to beat DF, I don't want give up hard learned knowledge to the wrong types. So when you pick the attendance, get trusted people to come along.
RDF ain't for everybody. It requires money and effort to make it work properly.
I'm going to try and save you a lot of pain and treasure by side steeping the RDF learning curve.
This next note is a highly edited back and forth with a genuinely annoyed control Op.
Since my last email, we've had some updates.
(Before you accuse, make real sure. I have a nasty trick that works nearly every time.)
(Pays to make sure. 
One bad accusation and we all look like ninnies.)
I'll record the machine 24/7 if I have to as well.
(Recordings are at best 'hear say' and not too useful.
The FCC had an enforcement action in NYC some years ago. 
Someone was giving bad ATC (Air Traffic Control) signals on an approach to JFK airport.
(Consider this, when a pilot of a 747 get’s told to change runways at the last moment and he can see another plane already there. 
That’s what this clown was doing, issuing bad instructions to flyers that could result in horrendous loss of life.) 
The FCC and the federal Marshals had to kick down the door of an apartment, and visually see the bozo pressing the PTT switch, they did it but it was not easy.
Think about rules of evidence.
The better the evidence the less explaining you have to do later. 
Some arguments you can't win without sticking the facts up people’s noses.)
{It’s human nature that people believe what the want to believe and the facts are irrelevant. We have this huge ability to lie to our selves and to others. Keep in mind, no matter how fancy the technology, this all comes down to humans behaving badly, and nobody likes to be caught.}
(That's a good plan. 
At the 'kill' we can do a few things to cut down the chance of error.)
…confront him face to face if need be.  
(There is a better way.
When I 'nail' a suspect they are usually making noise, or have a live microphone open in their area.
I get a power air horn, like the kinds that marine stores sell. 
Self contained gas unit, and a loud trumpet. 
Think of the kind you hear at a hockey game.
When my bozo is transmitting, I let fly with the horn. 
The sound is across the yard and through the radio before our idiot can un key. 
We usually have a game of "peek a boo" through the blinds, I flip the bird and drive off.
This way the subject knows they have been had, and by who.
In my experience 75% of the time, the problem stops.
So if your target is doing this in a vehicle ... just add a step or two.
Dose he know what you look like? 
If so, then someone he has never met should be the one to spring the trap.
Can you sneak up on the vehicle as a pedestrian, perhaps with the rx audio from a hand held fed to a pair of IPod style ear plugs? Hide the radio; it's just there to tell you when the transmitter is 'on'.
Get next to the car, and when a rude transmission happens, blat with the horn.
Just be sure to turn down the radio first. That horn is going to be loud!
Make eye contact, flip the bird and leave.
Say or do nothing else provocative.
Side effects.
Most people would be too stunned after getting caught red handed.
Think of the most embarrassing thing you ever got caught doing. 
I have a list I ain't proud of. 
Don’t ask me about it.
Some people recover faster than others. You have to be ready for that.
{Remember what I said about catching the tiger, what happens next is critical}
Might want to have a 'get away car' handy so you can get in and have someone else drive you off and out of the way. 
If you get chased, run to the back of a Police station.
Try not to bring weapons with you, that just looks bad in the after action report.
The Air Horn is nasty enough. 
As fun as it might be to set it off right in an ear, 12 to 15 feet is close enough.
At a distance it’s a nasty scare, too close it's an assault, and your moral high ground is eroded.
When you act, say and do nothing on the radio about it.
Might want to keep a recorder going at home so you can 'document your kill'.
{I used to use a 6 hour VHS recorder, and a video camera at home.
The camera watched a radio scanner and a fancy 24 hour clock. 
The audio part of the scanner was fed into the VHS recorder. 
So when I made my ‘kill’ the tape logged the sound of my air horn going through someone’s radio at a very specific time and frequency. 
A poor mans data logger.}
You’re going to be upset, angry and at such times people tend to say things that they would never say when calm.
I the gun community we have an expression 'shoot, shovel and shut up'.
Give your self some down time after the 'kill'. 
You’re going to be upset and angry that you had to spend a chunk of your life teaching someone who should know better not to be an idiot. 
Face it none of us like to ‘correct’ the bad behavior in others. 
Conversely none of us want or need bad behavior inflicted upon the collective group.
Before the ‘kill’ one might want to tip off a few others privately, via phone either before or after the event. Remember OPSEC.

More information about the Tacos mailing list