How to Build and Run a Pirate Radio Station
This document’s intended for non-technical users.
Radio communication made easy: FM band 87.00MHz～108MHz
There are a few basic components to make a working radio station;
Transmitter: Transmitters are a device that take audio input signals from a microphone or PC sound card, converting the input to electrical waves sent out through the feed line to the antenna, allowing the signal to be transmitted and received. A transmitter power output of only 10 watts with a good antenna will cover a small city. For pirate radio I suggest that you keep the power under 100 watts, where 20 to 50 watts is nominal. If you want more power, you can add an amplifier to your transmitter. High power comes with its own set of problems and danger that is beyond the scope of this document.
Antenna: The antenna delivers the electrical energy from the transmitter to the open air, allowing the signal to be sent and received. Sectora antenna are utilized when you want a directional pattern and require a wide signal path. Yagi antenna are high gain and are very directional. Omnidirectional antenna are most often used, providing a uniform signal in all directions.
Feed Line: This is the coax cable that connects the antenna to the transmitter. Most transmitters will use a 50ohm or 75ohm coax. With a coax run of under 100 feet, less than 100 watts, basic coax will work fine. Common coax types include, RG-6, RG-8, RG-58, RG-213. Match your coax and connectors to your transmitter and antenna specification. Your local radio shop will often provide the coax with the connectors attached.
Input Device: Typically broadcasters use an expensive microphone and a multichannel mixer to enable various audio sources to enter the transmitter. A PC sound card and the PC’s mixer will work perfectly well, allowing you to record your broadcasts and adjust audio levels for best sound quality.
Performance: The higher the antenna, the better radiated power, a better signal. Install the antenna on a roof or in an attic, balcony, tree. Also, locating the antenna just a few feet off the ground in an open field works well. It is important to keep the antenna away from solid objects and metal as this will de-tune the antenna. Most people are inclined to throw power at a weak signal problem when the real factor in getting the signal out efficiently rests almost entirely with the antenna. Matching or tuning your antenna is done by measuring the ‘Standing Wave Ratio’ or SWR. Standing waves happen when the transmitters electrical waves are reflected back along the feed line from a de-tuned antenna, this can cause equipment failure. A well ‘matched’ antenna is very important, a high SWR will negatively affect performance. There are simple and effective ways to measure SWR and tune the antenna for the lowest SWR. The easiest way to adjust the SWR is to lengthen or shorten the driven element. By adjusting the length of a vertical antenna will fix SWR problems. A SWR meter is an inexpensive tool every radio operator needs.
Detection Avoidance: Broadcasting over several hours, then stopping is an effective way to reduce detection. Do not broadcast continuously or on a schedule. Broadcast when it is the most difficult for the authorities to find you, when they are busy, sleeping, on holidays, etc. Broadcast when they are at not expecting you. Radio locating is easy in theory but its never exact. Having said that, it is important to be aware of your neighbors and any slow moving vehicles with sophisticated antenna driving up and down your street. If you think you have been detected do not panic. Be calm and stop broadcasting. Usually the authorities do not have an exact location and even if they do know the exact location, they require a warrant in most Western countries to invade the premises. Radio police, like the FCC are a bureaucratic nightmare to their own employees, they move slowly and it can take weeks if not months for the authorities to come up with a warrant to search a given location. You should have plenty of warning, move your equipment to a new local as often as you think necessary. It is always a good idea to move the base station with regularity, every few weeks or couple of months depending on the pressure exerted by the authorities. By moving it with regularity the bureaucracies will not keep up to you. Operating from a mobile vehicle is most difficult to detect. Transmitting from a vehicle is easily done. Typically you will trunk mount the transmitter and run the cable to a laptop, the operator can control the broadcast from the comfort of a passenger seat. A mobile broadcast antenna for the FM band looks like most police car or CB radio antenna. Drive safely and automate your mobile broadcasts as much as possible.
Safety: Do not handle or touch an antenna during transmission (RF burns are cell popping painful). Do not open or try to repair your transmitter unless you are qualified. Do not run your transmitter without a proper antenna attached. Do not climb near or locate an antenna near power lines. If you are running your broadcasts from a vehicle, always connect the transmitters power connection directly to the battery to avoid power problems. You may need to use a DC to AC power inverter that is also connected directly to the vehicles battery. Always ground your transmitter and antenna. A proper ground keeps spurious RF noise to minimum and helps if lightening strikes the antenna. If your are not sure about something always ask questions.
Summary: A basic transmitter, coax, antenna and a PC is all you need for a pirate radio station. You can get as sophisticated as you want. Personally, I like a minimal setup, it’s less complicated, fewer points of failure and it’s more portable. A budget of $1000 to $2000. will get you an excellent set up with everything mentioned in this article. Most of all have fun!
Sources for Transmitters:
http://www.radio-locator.com – Find radio stations and open frequencies in your area
http://davemartinsmusicblog.blogspot.com – The ramblings of a pirate radio operator
http://blockyourid.com/~gbpprorg/lpfm/index.html Schematics and technical resources
This is a highly recommended knowledge set. Get your license and enjoy the earned skill and capability. Digital modes, Slow Scan and Fast Scan TV, Satellite, Earth Moon Earth bounce (EME), and its easier than ever to get a license! I will help… details soon.
11 meter / CB Radio
Un-licensed HF Band – 26.900 – 27.750 mhz
FRS – Family Radio Service
400.000 mhz low power un-licensed
Fun hobby, listen to stations from around the world, Pirate Radio station are often heard near 6.800 – 6.950 mhz.
It’s best not to jam signals. Free speech is free speech. However, if you are embattled, jamming can assist in defense of freedom. Jamming at street level with hand held radios works very well. By keying over top a signal, on the same frequency will disrupt it. By injecting a 1000hz tone, RTTY, SSTV or other audio will make it very difficult for a nearby receiving station to understand the message.