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Pirate Radio

What follows is an edited version of a series of articles describing how to get into Pirate Radio. Pump up the Volume.

This article also includes random stuff about building a cable descrambler. Think of that as a “bonus”.

Thanks everyone for all your interest. I have lots of stories to tell and neat information to share, but I think the single most useful thing I can do for anyone interested in pirate radio is to turn you on to this company:

Panaxis Productions
PO Box 130
Paradise, CA 95967-0130
(916) 534-0417

This is a one-person shop, owned by Ernest Wilson, a cool guy with the hippest possible attitude. He puts out a bimontly (or whatever the term is for “once every two months”) newsletter called “ERN: Experimental Radio Newsletter” which features discussions of who’s pirating, who’s been caught, how you can get into legit (or illegit!) broadcasting, transmitter circuits, circuit theory… a neat publication! I forget what the subscription costs, but it’s mentioned in the $1 catalog you should send for right this minute!

The catalog contains various exciting projects, including bugs, am and fm transmitters, stereo generators, compressor/limiters, filters, linear amplifiers, jammers… cool stuff! These projects are available in various forms: you can buy just the plans, which often include a foil layout for making the PC board, or you can buy plans + ready-made PC board, or for some projects you can buy a complete kit (talk about classy: he throws in wire and solder!).

The laws regarding the sales of some of this stuff are strange. You can be assured that Wilson will do whatever is remotely permissible, however he has taken some heat for some of the ready-made items he’s sold, so recent catalogs are perhaps a bit less fun than they have been in the past. However, the laws are so screwy, he’s told me he expects to be able to redesign some of the equipment to get around the restrictions.

For example, my very favorite project from his catalog is the 10 Watt stereo FM transmitter. It’s a complete 10 Watt FM stereo radio station in a compact package. Now, this project consists of four circuit modules: stereo generator, 500mW exciter, power supply, and 10W power amp. Turns out the FCC has passed a law restricting the sale of RF power amplifiers (to stop ham shops selling linears to cbers), so there’s some configurations in which he cannot get away with selling the 10W power amp. But he can redesign the transmitter so the whole 10W exciter is on one circuit card and there’s no standalone amp, and THAT’S okay. Ain’t that America?

I haven’t checked with Panaxis in a while to see what the latest is, so that’s your homework for today. Call or write Panaxis, [tell him I sent you so he’ll be less paranoid about me possibly being the heat when I call him next time!] send for their exciting catalog, and subscribe to the Experimental Radio Newsletter.

Next time: for those of you who are not electronically inclined, you *can* assemble a pirate station without having to build any equipment! I’ll tell you how.

Method #1 to Get On Air:

Hello again, fellow hackers! This posting was going to be about getting on the air without having to build your own equipment, but I’ve pushed that ahead to sneak in a topic of interest to radio pirates and others: telco loops.

A loop is a pair of phone numbers that are connected to each other, so that if you call one of the numbers, and I call the other one, we’ll end up hearing each other. There’s no ring, but you’ll hear a click as the other end connects. They are used by the telco for legit testing, but have other uses! For example, a pirate could announce one of the phone numbers over the air, and then call the other number and wait for requests to roll in. It’s not your number, and as soon as you disconnect from your end, your association with the loop is dissolved.

Typically one “side” of the loop will answer with a steady or pulsing tone (about 800 Hz), and the tone will go away when the connection is established. The other “side” is silent except for a click when the connection happens, plus of course the audio from the other end while connected. I prefer to call the “silent” side and wait until I hear someone on the other end.

Phone companies will often use numbers of the form xxx-99xx for testing. In my area, the loops are xxx-9904 and xxx-9905. (xxx could be any exchange in your area, or even outside if you dial 1+ and pay.) You can identify loops by their behavior as I described it above. There’s one BIG catch — phone companies are onto our use of loops, so they often mute them when they’re not in use (legit use, that is!). When muted, loops act normally except that audio is not passed across, so you need two phone lines to find a good loop. You might have to try several exchanges before you find a working combination, if at all. But, if you do manage to find one, it sure is nice! Now I can’t promise that you’re untraceable, but it’s a lot more complicated. Pirate stations have been known to use loops, as I did when I was pirating, and I felt reasonably safe. Then again, I might have been fooling myself!

With a sufficiently slick computer setup, you could automate the process of hacking out loops (something I’ve never done). With two modems and two phone lines, you could set one up in answer mode, the other in originate mode, then set them both to dialing known good guesses. (In my area, I’d try all known exchanges with 9904/9905). If the carrier ever goes through, you’ve got a winner!

Your homework assignment is to try and find at least a muted loop (which could be unmuted in the future, so it’s not useless!) in your area. The xxx-99xx form may not be universal, or they may only use a subset of those, like 9950 and up, or who knows. I recommend scoping out the territory during the day, so you’re still 100 times less annoying than telemarketing slime. You’re also more likely to find an operable loop. You may even encounter an astonished telco worker who was using the loop at the time! Just say, sorry, you were trying to call radio station [your call sign here], and hang up!

Method #2

This installment will be about how you can hack your way onto the airwaves without having to build equipment, as promised. I feel this is an important sideline because not everyone who would otherwise have the interest is an electronics whiz. I still prefer to build my own, as I have more control over the product, and it’s a blast! Plus the equipment is not as easily recognizable for what it is.

To drastically simplify things, in order to get on the air you need the following:

  1. An audio source.
  2. Some sort of transmitter.
  3. Optionally, an amplifier to boost your transmitter’s power.
  4. An antenna.

Let’s look at these components one a a time, and consider how you might obtain each, without having to be a soldering expert.

1. Audio source.

Gotta stereo? A boombox? A tape player? You’ve got part 1 covered!

2. Transmitter.

This is of course the biggie. It takes your audio signal and “modulates” a radio signal with it, putting your program on the air. I’ll only consider AM and FM broadcast for now. See the possible sideline hacks at the end of this posting for other possibilites.

The simplest solution to this is almost too simple — just buy a real, professional broadcast exciter. There are lots of ads for used equipment in

Radio World (magazine)
Industrial Marketing Advisory Services, Inc.
5827 Columbia Pike
Suite 310
Falls Church, VA 22041
(703) 998-7600 (voice)
(703) 998-2966 (fax)
Anyone can buy and sell this stuff, so you probably won’t be asked any questions. A beat-up, lower power (100W or less), old (tubes, perhaps) exciter will go for $300 or so. You might find fixer-uppers, and depending on your skill, you might be able to get them going, or find a friend who can. The price can go way up from there, if you want to get at all fancy.

Incidentally, they have all sorts of equipment of use to broadcasters in there: reel-to-reel tape recorders, cart machines, audio signal processors, stereo generators, microphones, record players, mixers…. you name it! It’s worth getting just for the want-ads.

If you go with FM, you might want to broadcast in stereo, in which case you would need a stereo generator. Panaxis has these in kit form, of course, and they’ll even sell you a wired-and-tested circuit card, but you’ll still have to provide a power supply (+ and – 12v) and an enclosure. If you’re not so inclined, you’ll have to find a stereo generator for sale in Radio World or a similar publication. Expect to pay about $300 for a decent old, used one. Now you know why radio stations don’t pay their employees much. :^/

[Part of the allure of stereo broadcasting is getting the STEREO indicator to light up on the receiver, which can be faked! You just inject a phony 19 KHz pilot signal and the stereo lights will glow…. a fun hack in itself!]

Besides buying the ready-made, genuine article, there are other possibilities. An FM wireless mic (a la Mr. Microphone) is actually a very small and very crippled FM radio station, which can be improved upon. You can take the wires from the microphone element, and run the shielded cable to a stereo instead. You’ll need to reduce the level since stereos put out much more voltage than microphones. This can be done with a couple of resistors. Also, you can disconnect the builtin sorry antenna and run coax to a cable amp, which will exhibit some gain. You can even stack cable amps for extra gain. Some of the most powerful cable amps made (which aren’t cheap, and aren’t at Radio Shack) are strong enough to drive 2M ham linears, and presto! you’ve got as much power as you want. Not very clean, neat, or economical, buy hey.. you didn’t have to build anything!

3. Optional power amplifier.

As I mentioned earlier, cable TV amps will exhibit gain in the FM broadcast band, and you can use these to boost feeble “mr microphone”-type signals. Within reason, you can stack them for extra gain. 2M ham linears, such as those made my Mirage, will also provide gain at 100 MHz, though they’re unlikely to give you their full rated power. The model I used was a Mirage which could put out 80 watts on 2M. At 100 Mhz, after retuning (just turning a screw or two) you could still get a solid 50 watts. Not bad!

There are many broadband amateur linears available that will work (at least marginally) on the AM broadcast band. Most will be rated from 1.8 to 30 MHz, since those include frequencies hams use (note that this includes the 27 MHz cb band). The AM band ends at 1.6 Mhz which is very close to 1.8. Sometimes, it’s close enough that the amplifier will still work. [note: there’s some laws regulating the sale on these, because they’re capable of amplifying cb signals. Your dealer will fill you in with their version, which may be nonsense they made up because they don’t like you, but it’s more than likely really the law. Anybody who knows want to help me out here?] Some older amateur linears just work on specific ham bands, and many omit 10M and CB on purpose, so they can be sold without hassle to hams. Any of these that will do the 160M band (1.8 MHz) can probably be converted without too much hacking to operate at the top of the AM band. But that’s beyond the scope of this message.

4. An antenna.

With a nifty device known as an “Antenna Tuner” (which you can buy from ham supply stores with no troubles — or build for much cheaper, if you’re into that), you can use just about anything as an antenna. For AM, you want BIG and TALL. Put up a big pole (40 feet minimum) and insulate it carefully from the ground, anything metal or conductive, etc. Use ropes to secure it, etc. You can feed the bottom of this pole with the signal from your AM transmitter, fed through your tuner. You’ll need a power/SWR meter (indispensible tool, also easily purchased from ham stores. I don’t recommend building one… they cost little enough) to adjust the tuner, and you can get excellent results. A friend of mine put a 60W AM station on with such an antenna and covered a broad section of town. [In fact it worked well enough to draw some unwanted attention from local broadcasters who didn’t want the competition, and they knew who he was because he bragged about it, so they quietly suggested he shut it down, and he did. He just wanted to experiment, anyway. The experiment was a success, and he left the air.]

For FM, you can use a regular VHF tv antenna, or a special FM receiving antenna from Radio Shack. These are not the *best* choices, but they’re easy to come by and work ok, if you use a balun (a little transformer dealie like you probably have on the back of your TV where the cable hooks up) to match the 300 ohm antenna to the 50 or 75 ohm coax coming from your transmitter. There are some great ready-built antennas for FM broadcasting which are a little hard to get, but cost very little ($20 or so) and work exceedingly well. This article is getting too long — I’ll cover these next time!


Well, I didn’t give out as much information as I wanted to, but at least, after reading this, any of you who are interested can feel confident that what you’ve been thinking about can be done, and you can do it if you want. There are much better ways to do all of the above, but they all require more technical prowess. The purpose of this article was to establish the minimum technical proficiency required to at least get you on the air, not necessarily with any finesse.

Other Hacks

I’m just going with the flow here, so if you’re interested in any of the following sideline hacks, let me know and I’ll touch on them:

  1. Abusing cordless phones and baby (room) monitors (both spying and injecting your own signal)
  2. Setting off weather alert radios
  3. Having free reign on the vhf and uhf public service bands (police, taxis, marine, security, mobile telephone, etc.)
  4. Having free reign on the mf and hf bands (shortwave)
  5. Getting CB radios to do more than the manufacturer supposedly intended (more channels, more power)
  6. Having free portable telephone capabilities without stealing service (this can be done legally)
  7. Embedding auditory subliminal suggestions over any other audio, safely and undetectably (i don’t say it does any good…just how to do it!)
  8. Listening in on a phone line without telltale clicks or load increases (you use capacitors — next!)
  9. Pirating cable television

Cable TV Pirating

Standard disclaimer: I’m not suggesting you try any of this stuff. I’m giving you information, and hopefully you won’t be irresponsible and go off and get yourself into trouble. “For entertainment purposes only!”

I’ll be continuing my series on pirate radio hacks tomorrow, but today I wanted to clear up a misunderstanding, and document a delightful cable tv hack!

When I said “cable tv pirating”, I didn’t mean stealing cable, or stealing premium services. If you are getting cable, and on one of the channels that HBO or somesuch is normally found you get instead a flashing picture and noisy audio that sounds like “beebeebeebeebeebeebeebeebeep!”, that’s a primitive jamming technique that can be defeated with a primitive circuit (all passive: two coils you can easily wind yourself (take my word — it’s easy!), a potentiometer, and a variable capacitor. That’s the whole circuit!)

Let me draw it for you techies out there:

Cable Descrambler Schematics

Coils are 4T of #20 wire, 1/4″ inner dia., spaced to be 1/2″ long

This is nothing more than a notch filter. This particular method of preventing nonsubscriber access to premium services is being phased out, but if you suffer from the symptom, the above is the cure. They are actually sending all the information contained in the program (another good hint is that you can usually tune for sound but no picture, or a ghastly picture but no sound, just beebeebeebeeping), but they jam it with a narrow band, but high energy, jamming signal. The filter eliminates this signal (the resistor adjusts the width of the notch (the Q for you techies), and the capacitor tunes it to the right frequency).

If there is interest, I’ll post more detailed plans including where to find the parts, physical layout and construction, etc. But the above should be enough for some of you. Anyway……..

THAT ISN’T WHAT I MEANT! (but since some of you brought it up in your letters, there’s at least some info for you).

What I meant was getting your own signal to appear on a cable TV channel. I’ll describe this by relating a hack I heard about after the fact!

Here in Albuquerque the PBS station is channel 5. The cable company receives the signal off-air with a big beam pointed right at channel 5’s transmitter, and rebroadcasts the signal to the happy subscribers. Channel 5 goes off the air a little after midnight, and when that happens, the cable company does nothing special. Their receiver simply picks up the noise on the empty channel, faithfully retransmitting it over cable.

Aha! Some of you are already onto the hack…but it gets better. Our hero just happened to have an RF modulator like you use with computers and video games that worked on channel 5. They exist. Anyway, it puts out a very weak signal (suitable only for driving a tv directly), but weak signals can be turned into strong ones. He stacked a couple of cable amps to boost the power, and — get this — did the whole thing from his car!! He got a power inverter, a VCR with a very special tape (I think it featured something deliciously naughty, but I heard the story a long time ago), the modulator and cable amps, and hooked it all up to one of those cheapie wall timers (mechanical) that turns things on at a certain time. He used his car’s ordinary antenna for transmitting.

So armed and ready he parked his car right near the cable tv building, set the timer for a little after midnight, and caught a ride with a friend (who had cable!) to watch the fun. The signal was reasonably clear, and they were assured of a nice large audience, because the real channel 5 had just barely switched off. It didn’t make headlines, but it certainly made one hacker’s night a night to remember! I think I’ll call him “lieutenant midnight” :^)

How to Build a Cable Filter?

Okay, I apologize. My previous post of the cable filter was a teaser. It really didn’t have enough info to get the job done… so here’s the real thing, by popular demand! My apologies to those of you who might have started down some wrong paths. Let me know how you get on, and feel free to ask questions. This is a limited medium, and in any case, I’m a limited instructor.


If on some cable channel, you get audio that sounds like a loud “beebeebeebeebeebeebeebeep!” (roughly 5 beeps per sec, audio tone in the ballpark of 1000 Hz), and you can get the program audio by tuning away from the center of the channel, you are the victim (and soon the conquerer) of a primitive narrow-band jamming technique. Many cable companies are moving away from this method because it is so easily defeated. Heh.


You’ll need to have some electronics experience, but I’ve kept this pretty nontechnical. It’s an easy project, as they come. You could become very popular among your friends. Of course I mean by inviting them over to watch your cable, *not* by building boxes for them. Heavens, I didn’t mean that! Also this design is for tv channel 3, and is meant to be used after your cable converter box. If you have a modern “cable-ready” installation, and the channel in question is nowhere near tv channel 3, you might need to change the coils and/or capacitor.

  • 1 aluminum project box (eg. radio shack 270-238)
  • 2 female chassis-mount F connectors (eg. radio shack 278-212)
  • 100 pF variable capacitor (open air, chassis mount type)
  • 100 ohm linear taper potentiometer (again, chassis mount, wirewound not ok)
  • some 20 ga. solid core wire

(see text for acceptable deviations from above parts list)

I’m sure there are plenty of great parts supply places where you could find the cap and the pot. Check your local yellow pages. If all else fails, try Electronic Surplus Co. in Albuquerque. (505) 296-6389

They definitely have all this stuff, and real cheap, I might add! Plus the owner, Dave (not me), is very knowledgeable and friendly. He’ll probaly know right away what you’re building, and might even offer advice.

The schematic, again, looks like this (it’s a pi notch filter):

Pi notch filter schematics for Cable Scrambling

Here’s my attempt at a pictorial. You are seeing a side view of the opened project box. Uhhh you might get a better idea of the wiring from reading the WIRING text below. Sorry I’m not much of an artist!

Wiring of project box - Cable Descrambler

First you should mount the pot, cap, and connectors to the box, and wind the coils:

BOX: The box should be metal both to serve as a shield against interference and to make wiring simpler (the ground connections are made for you).

CONNECTORS: These F connectors are chassis-mount and thus they ground the shield of the coaxial connection directly to the metal box. This is useful and important. You need only connect wires to the “hot” terminals. I recommend attaching them on opposite ends of the box, since the box is wired inline with the cable. Where you put the connectors won’t affect the electrical operation, as long as you wire it carefully.

CAPACITOR: The capacitor should be a chassis-mount open-air type 100 pF variable. Don’t use anything less than 100 pF, but you may use larger, up to 400 or so. (They don’t *make* variable caps much larger than 400 pF!) All variable capacitors have two sets of plates which move through each other without touching. There should be at least one terminal (solder point) connected with each set of plates (just looking you should see how they are connected). Nearly all var.caps. have the moving plates connected electrically to the control shaft, and some also have the moving plates electrically connected to the mounting bracket. This is unfortunate, because this particular circuit requires both sets of plates to be insulated from ground. So, you must use a plastic control knob for tuning (otherwise the capacitance would change too much when you removed your hand after tuning it), and you must make sure that both sets of plates are electrically insulated from the chassis. There are capacitors that are easily mounted this way, and there are those that have the mounting hardware shorted to the moving plates, which are very difficult to use in this project. Email if you need help…. if you measure a short from either set of plates to the chassis (before the coils and pot are wired in), your circuit won’t work.

POT: The potentiometer should be a 100 ohm (75 to 200 should work okay) linear taper pot, and *not* wirewound. Get the chassis-mount type (not a trimmer). There are no dangers as with the capacitor above. In fact, this circuit calls for two of the terminals (an end one and the center one) to be connected to each other and wired to the case. You can’t solder to the aluminum box, but you can twist a bare wire around the shaft before mounting the pot, and it will be pressed against the box, making a solid connection. My favorite way to do it is a little different: I rough up a corner of the metal back of the pot’s surface, and solder a wire to it, and to the two terminals to be grounded. As soon as the pot is installed, its metal surface contacts the box, and the connection is made :^)

COILS: You’ll need some solid core, 20 ga. wire and a bic pen or some other object about 1/4″ in diameter. To make a coil, twist the wire around the core (the pen, screwdriver, or whatever), counting off four turns. The turns should be spaced about 1/8″ apart from each other. You’ll want to cut it so there’s a few inches free on each end for wiring the coil into the circuit. You’ll need two of these coils. (This same wire is suitable for all other wiring in this project.)

WIRING: Generally, you want all the wires and coils to be as far away from the metal box and from each other as you can manage. Space things out in there for best results. Also, keep all leads as short as is practical.

  1. Ensure that the grounded terminals of the pot are in fact connected electrically to the case. Also ensure that the moving plates of the variable cap are not shorted to the case.
  2. Solder a wire from one F connector to one set of the cap’s plates.
  3. Solder a wire from the other F connector to the other set of plates.
  4. Connect a coil from one set of plates to the ungrounded terminal on the pot.
  5. Connect the other coil from the other set of plates to the same ungrounded terminal on the pot.

HOOKUP: This box is designed to filter narrow band noise around TV channel 3. Unless the premium service you’re trying to get is transmitted on 3 already (as it happens to be here in albuquerque), you’ll want to install this box after your cable converter box but before your tv. If you’re modern and don’t have a cable converter, you may have to do some investigation and redesign, or it might work anyway if it’s still on a lower VHF channel. (Or you could install if after your VCR, but then you could only watch that channel, not tape it.)

If the box is constructed carefully, it should introduce negligible loss on all channels, and enable reception of the jammed channel once tuned.

TUNING: It takes a while to get the hang of it. Set the resistor to max. resistance (what direction to turn it depends on how you wired it…don’t sweat it if you’re not sure), then start with the capacitor and alternate from one knob to the other, back and forth until the picture is best.

ENJOYMENT: For best results, tell your friends, but don’t sell any. People have been busted for selling these, but if you’re aware that you don’t want to invite cable tv people into your house until you hide the box, you’re in practically no danger. If you’re paranoid about the cable tv people coming around and checking your cable from the outside to find out what’s connected to it on the inside… it’s theoretically possible to detect this box if it’s connected directly to the cable. Any sort of converter or amplifier in between is sufficient to make it impossible to detect.

Well, I wish you all the best of luck … do report your successes and failures, and feel free to ask questions.
I’m just going with the flow here… we’ll get back to pirate radio eventually!

By the way, everything I’m relating in this article was published as a front page story in UT Austin’s excellent student newspaper, The Daily Texan, in 1976. It was controversial, but the Texan was able to successfully defend its right to disseminate the information. So, this is nothing new *or* secret!

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