How Do I Build a Low Power FM Radio Station?
A low power FM radio station offers individuals or small groups the ability to go on the air and communicate with the general public using FM radio waves which can be picked up with any FM radio receiver. While a low power FM radio station can refer to a small commercial radio station, the term usually used refers to micro-power broadcasting, where individuals or small groups build their own small radio station that can only reach a limited area. In many cases, low power FM radio stations or micro-power broadcasting can transmit FM radio signals from distances of a few feet to a few miles in radius.
Generally speaking, most low power FM radio stations require a license issued by the FCC (Federal Communications Commission) in order to broadcast, especially if their message is commercial in nature and if they transmit for a distance greater than several meters. However, many radio hobbyists can transmit FM signals legally, as long as they keep their transmitter’s output power to within stated legal limits. Contact the FCC for complete information on low-power FM stations, licensing procedures and regulations.
Equipment Needed to Start a Low Power FM Radio Station
You don’t need a lot of equipment to start a low power FM radio station. With today’s electronics, the quality and ease of use will be much simpler and more reliable than equipment was just a couple of decades ago.
For the most part you will the need the following equipment:
An antenna (the size will depend on how far you would like to transmit your signal). However it can range from a few feet to over 30 feet high.
A transmitter. A transmitter is the actual technology that transmits the FM radio waves on the frequency you desire. Transmitters range in power. It should be noted that the more power a transmitter has, the further the distance an FM signal can travel. In addition, the cost of a transmitter rises as power output increases.
An audio source for those that would like to transmit music such as an MP3 or CD player and a microphone to transmit voice.
Coaxial Cable to carry your signal from the transmitter to your antenna. Most hobbyists use RG-8 or RG-58/U (52-ohm coaxial cables).
A compressor/limiter. A compressor/limiter is a piece of equipment that keeps the sound level of your transmission even. You don’t want your audience to receive transmissions that are very low, while intermittent sounds that are very loud are transmitted. A compressor/limiter ensures that your volume level will remain constant.
Putting Your FM Radio Station Together
Typically, every radio station’s equipment is different and will require a customized installation. However, if you purchased equipment as a kit, instructions will be provided. For newcomers, you can easily contact the manufacturer of your equipment or a local amateur radio club to receive the help you need.
How Much Power is Necessary in Order to Get a Certain Transmission Distance?
This is a question that is often asked, and the answer depends upon many circumstances including the height and quality of your antenna, the power of your transmitter, the region you are transmitting from, what kind of signals you are transmitting, the sensitivity of the listener’s radio equipment, and whether or not there are any building or structures blocking the signal.
Selecting an FM Radio Frequency to Transmit On
Please note that it is extremely important to transmit on the proper radio frequency. Transmitting on the wrong frequency can interfere with emergency services and air traffic systems that use radio frequencies to communicate with mobile and hand-held units.
Generally speaking, FM radio is transmitted on frequencies ranging from 88.1 to 107.9 MHz. Each FM station is separated by a 0.02 MHz frequency interval. Remember to check with the FCC or your local government to determine which, if any FM frequencies you are allowed to transmit on.