How WATD Works

How WATD Works:

Everything you hear on the radio starts as electrical signals. Usually those signals are created by a device called a microphone which translates sound into electrical energy. Sometimes that energy is used to make a recording. Sometimes it is broadcast live. Our job in the WATD Engineering Department is to make sure those sounds our announcers and news people select reach your FM radio as clearly and faithfully as possible. Here’s how we do it

Our radio station functions technically very much like a giant home entertainment center. In our main air studio you’ll find a huge control console with several dozen inputs. Using sliding volume controls the station announcer can select from many sources including CD machines, turntables, minidisk players, reel-to-reel and cassette tape players, computers, audio editors and remote pickup circuits.

Air-Studio Audio Console

A home stereo connects the audio source you select to speakers wired to the set. An FM broadcasting station replaces those wires with a radio transmitter which converts the electrical waves which would power a speaker into radio waves which are then radiated by an antenna . The frequency of a station is actually the number of radio waves it transmits every second. WATD-FM operates on 95.9 Megahertz which means our antenna radiates ninety five million nine hundred thousand radio waves every second. Other FM stations in our area use different frequencies in the FM band which includes 100 channels from 88.1 to 107.9 Megahertz. The audio from our studios is modulated onto our 95.9 Megahertz carrier signal. FM radio receivers contains a special circuit to select only the frequency of the station you tune to. Another special circuit removes the audio information from the modulated carrier signal, then turns it into electricity which is fed to a set of speakers which convert the electricity back into sound.

WATD Studios in Marshfield, MA


Most visitors to WATD see only our studio building which houses our business offices, studios, newsroom, website office, and engineering shop. But our actual radio transmission site is located on a five acre tract of land off Grove Street in Marshfield about three miles east of our studios. We own two towers here. The tallest one is 460 feet high and supports our main FM antenna, receiving antennas for our two-way radio system and remote pickup units, microwave links from our studios, antennas for Marshfield Fire and Police, and cellular arrays for a number of wireless telephone companies. The other tower is 330 feet in height and supports our backup FM antenna , our two-way radio transmitting antenna, microwave links back to the studios, and several more antennas for wireless phone companies.


Our Trip to Your Radio

The main WATD transmitter antenna

Getting music and words from our studios to you isn’t a simple process. Almost all the music you hear on WATD comes

from the hard drive of a computer which contains over 10,000 songs, station jingles, commercials, and theme music. The rest of our music comes from compact disks and good old fashioned vinyl records. Actually our music library contains about 2,000 cds and more than 10,000 records. News comes from the Associated Press Radio Network via a satellite dish on the roof of our building and from sound bites gathered in the field with cassette tape recorders or via the telephone. Those cuts are edited on digital workstations called Shortcuts.

All of the audio is mixed in our main control room . Except for the A.P. news feed, all programs are produced locally. For all but about eight hours a week there’s someone working in our control room 24 hours every day. The room vacant only during the “Off the Wall ” program hosted by Ted McCaw, who passed away recently. Because Ted was blind, he broadcasted from a studio at his home in Weymouth using a remote pickup transmitter to send his show directly to our antenna site.


The WATD Studios relay antenna, which sends signals to the main 95.9-FM frequency antenna for broadcast to your radio

At our antenna site stereo audio received by either microwave system can be routed to either of two stereo generators. These devices take the left and right audio signals and create what’s called a composite stereo signal. This “coded” audio can be connected to either our main 5,000 watt transmitter or our backup 1,000 watt unit. Up until a few years ago WATD used tube type transmitters which required frequent maintenance and had internal circuits containing over 5,000 volts. These were scary machines to service, especially in the dead of night which is when they always seemed to break. Today our new solid state transmitters use only 48 volts and they literally never break. Radio signals from the transmitters travel up our towers via coaxial cables which connect to our main and auxiliary antennas.

Our main antenna gives WATD its best range. Usually you can hear the station from Cape Cod on the South to the New Hampshire border on the North on a car radio. The South Shore towns we service are all located within a 20 mile arc of Marshfield but the extra coverage is wonderful for commuters.




The 95.9-FM radio frequency transmitter at the main transmitter site

We’re presently building a broadcasting studio at our transmitter site which will provide for emergency operation in case our main studio facility can’t operate for some reason. We’ll also be able to shut down our main studio for maintenance and still continue programming from our transmitter building.

The transmitter building also contains several receivers used to pick up remote broadcasts from news and sports events. Outputs from these units connect back to our studios via three dedicated microwave systems. There’s also a unit called an SCA generator which takes the audio from TIC, the radio reading service for the blind, and encodes it on our main FM channel. Special receivers in the homes of TIC clients decode this signal so listeners hear only the programming for the blind and not our main stereo program channel. Several microwave transmitters at our studio building send the TIC signals to a distribution center on Blue Hill near Boston where the programs are sent to other radio stations throughout the Commonwealth of Massachusetts. For more information about TIC , please click here.


When the Power Fails

WATD’s backup generator, now since upgraded!

In coastal areas storms frequently knock out electrical service. Of course, when storms come, that’s when listeners need radio the most. When the power fails, generators at our studio and transmitter automatically switch on and power up WATD within 15 seconds of the outage. We top off our fuel tanks every 90 days and test the generators weekly. If necessary, WATD can operate for over six days without refueling our generators. During the past decade we’ve lost less than two hours of air time due to power failures.




Main Radio Station Positions

Chief Engineer – Responsible for station equipment maintenance and live remote broadcasts

Announcer / DJ – Hosts all programs &  plays music. Entertains the audience with music and information.

News Dept – Delivers the news to the listening audience. Also passes along traffic and weather information.

Music Director – manages the station’s music playlist.

Production Director – Oversees the production of all station promos and commercials.

Account Executive – sells air time in the form of commercials and promotional tie-ins to businesses and acts as the key contact with the station and clients.

Traffic Director – acts as a link between the sales department and programming department. In charge of scheduling commercials and promos and provides proof of airtime.

About the Author

WATD online and on air contributors include, but are not limited to: The Associated Press, Precision Weather Forecasting, local news stringers and reporters, in-house news and internet media staff, State House and town hall reporters, freelance reporters, special feature reporters and producers, and on air radio hosts and personnel.