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AM Radio Station study - Washington, DC




Washington, DC AM Station List

To view a list of the AM radio stations licensed to operate (or proposed) within about 50 km of Washington, DC click here and the FCC web site will be queried for this information.

Note: No attention is paid at this point in this study to station antenna directivity (directive arrays). This factor greatly influences the strength of a station at any particular location. It is hoped that in the future a crude figure of merit can be appended to the station data plotted on the map indicating the direction of maximum radiated power; in the meantime, it would be safe to assume that any directional stations are directed toward the nearby population center they are licensed to 'serve' (the COL - city of license).

A website through which AM broadcast station coverage may be seen is www.radio-locator.com (formerly the "MIT List of Radio Stations on the Internet").

For instance, here is the nighttime coverage of WTOP, and here is the daytime coverage of WTOP; a 50 kW "DA2" (Directional Antenna with 2 different patterns - implying different directional patterns for day and night). The technical parameters supports this as well - WTOP feeds their three-tower array (at night) with different electrical parameters to provide tailored nighttime coverage.

Washington DC Daytime Station Allocations - Position Plots


Plots of stations licensed to operate (or proposed to operate) during daylight hours.

The data appearing adjacent to each plotted point is in the form: 

         Callsign/Freq (in kHz)/Power level/Distance (to the blue star)
New stations are identified as "New" in the callsign slot.

Day time stations, 600 x 600 pixels, *without* major roads, *with* major roads
- Map height, width = .25 degree

Day time stations, 800 x 800 pixels, *without* major roads, *with* major roads
- Map height, width = .5 degree

Washington DC Nighttime Station Allocations - Position Plots

Night time stations, 800 x 800 pixels, offset, *without* major roads, *with* major roads,
- Map height, width = .25 degree

Resources/links

- Home

- The FCC's AM Radio Database Query

- An excellent resource for understanding MW (Medium Wave) AM Broadcast propagation and the tools used to engineer systems and the stations at these frequencies:

Medium Frequency Propagation Prediction Techniques and Antenna Modeling for Intelligent Transportation Systems (ITS) Broadcast Applications

Abstract: This paper discusses the basic aspects of radio-wave propagation and antenna modeling in the medium frequency (MF) band. This band covers the frequencies of 300 to 3000 kHz. More specifically, we are concerned with the ground wave and the sky wave in the 300 kHz to 1705 kHz band.

The sky wave models described in this paper are valid from 150 kHz to 1705 kHz. The ground wave models described in this paper are valid from 10 kHz to 30 MHz. The AM Broadcast band of 535 to 1605 kHz is in this band and is planned to be used in the Advanced Traveler Information Systems (ATIS) of Intelligent Transportation Systems (ITS) for rural travelers. This system would provide information such as road conditions, road hazards, weather, and incident reporting.

The 285 kHz to 325 kHz band is presently being used for a differential correction signal in another application of ITS called the Differential Global Positioning System (DGPS) that will be used for precision location of vehicles. The propagation of radio waves in this band depends on both a ground wave and a sky wave and is quite different from propagation at any other frequency. Antenna modeling in this band is also quite unlike that in other bands.

This paper describes radio wave propagation together with antenna modeling in this frequency band so that a better understanding of the phenomena can be obtained for use in design and application of ITS subsystems. The models described here can be used for designing systems and making performance predictions for both of these ITS applications and any other systems that operate in this band. The paper contains descriptions of both sky-wave and ground-wave propagation models in addition to the methodology used to analyze antennas that operate in this band. A method of calculating and normalizing antenna gain for MF systems computations is also discussed. Some comparisons of measured and predicted data are also contained in the descriptions.

- Directional Antenna System Hadware - a paper by DLR's Jeff Littlejohn, Ron Rackley and Ben Dawson:

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