WROL 950 FM translator 100.3 FM

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Joining the ranks of FM translators greatly expanding the AM listening audience is WROL 950 Class D AM on 100.3 FM. WROL’s 5kW day signal from Rumney Marsh Reservation in Saugus is greatly attenuated to 90 watts at night to protect stations including:

  • WIBX Utica, NY
  • WKDN King of Prussia, PA
  • CKNB New Brunswick, Canada

This means WROL night coverage is poor in Boston and even core North Shore communities that are well within WROL day coverage.

FM translators for AM

In general AM Revitalization FM translators for AM stations attempt to provide the AM daytime coverage 24 hours a day via 250 watt or less transmissions in the FM broadcast band. Having an FM signal can be a boon for station advertising revenue–provided the FM coverage is not disrupted by unexpected factors such as illegal “pirate” broadcasters. The Feb. 2017 R&O extended the 60 dBu (1 mV/m) FM translator contour to the greater of the AM 2 mV/m contour or 25 mile radius.

Pirates vs. FM translator

Pirate broadcasting is cheap and effective. $500 of equipment & antenna on top of a church or apartment building provides 3-5 miles of coverage radius. This has led to widespread pirate broadcasts in urban areas to service ethnic/language niche markets not economically served 24 hours a day by other means.

Like WJIB 101.3 FM, WROL 100.3 will face challenges inherent to low power FM broadcasting. Specifically, the Dorchester pirate cluster currently operates on 100.3 FM and only a few months ago completed a major branding change to 100.3 FM from their previous home on 101.3 FM.

The Blue Hill Ave pirates have a cluster of three antennas for 87.75, 100.3 and formerly 105.3 MHz. The interference-free coverage and transmitter quality of 87.75 and 100.3 is nearly the same. The former 105.3 transmitter was of poor quality with distorted and splattering modulation. Transmitter power appears to be in the 10-100 watt range.

WROL W262CV 100.3 specifications

  • 40 watts
  • 42 21 46.35012 N 071 05 08.18621W (WGS84) Near the MIT Kendall MBTA stop, on the Marriott Hotel on Broadway (next to Microsoft NERD building).
  • height above ground: 90 meters


Licensed co-channel interferers include:

  • WKIT Bangor, ME
  • WHEB Portsmouth, NH 50 kW station that interferes with Dorchester 100.3 pirate, sometimes overriding pirate down to at least Chinatown area.
  • W262CL Brattleboro, VT
  • WKKB Middletown, RI
  • WFFG Warrensburg, NY
  • W262AS Bridgehampton, NY

  • WHEB is the primary limitation to coverage, particularly in the northeastern parts of Boston. However, one can merely switch to WROL 950 AM in that area.
  • Dorchester pirate is expected to reduce Boston coverage by nearly 50% of coverage area.


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