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92-594: WMGK (102.9 FM , "102-9 MGK") is a commercial FM radio station licensed to serve Philadelphia, Pennsylvania . The station is owned by Beasley Broadcast Group and broadcasts a classic rock radio format . The broadcast tower used by the station is located in the Roxborough section of Philadelphia. The station's studios are in Bala Cynywd . The station features Philadelphia radio personalities Andre Gardner, Matt Cord, Eric Johnson, and Tony Harris. On November 26, 1940,

184-520: A sports radio format as WPEN-FM , which was once WMGK's call sign. On April Fools' Day in 2015, WMGK reverted to its broadcast to its previous adult contemporary/soft rock music format; he announced WMGK "Magic 103" and played the old Magic jingles . The prank ended when a listener called in to the station to complain about the loss of classic rock. On July 19, 2016, Beasley Media Group announced it would acquire Greater Media and its 21 stations (including WMGK) for $ 240 million. The FCC approved

276-399: A 500 kHz frequency separation even when closer frequency spacing is technically permitted. The ITU publishes Protection Ratio graphs, which give the minimum spacing between frequencies based on their relative strengths. Only broadcast stations with large enough geographic separations between their coverage areas can operate on the same or close frequencies. Frequency modulation or FM

368-412: A bit outside the radio norm". The format has since been switched to oldies . WMGK is short-spaced to two other Class B stations: WNEW-FM NEW 102.7 (licensed to serve New York City) and WQSR 102.7 Jack FM (licensed to serve Baltimore, Maryland ) both operate on 102.7 MHz, a first adjacent channel to WMGK. The distance between WMGK's transmitter and WNEW-FM's transmitter is 82 miles, while

460-627: A construction permit to move the station to 102.9 MHz on July 12, 1948. A new license for operation on the new frequency was granted by the FCC on August 17, 1950. WPEN-FM was one of the first two FM stations to be licensed for SCA (subcarrier) service. The station filed an application for the SCA on October 12, 1955, with the FCC granting the authorization on July 1, 1956. Subcarriers could be used to send special programming to subscribers, such as background music for stores and restaurants. From its founding until

552-510: A contemporary jazz show called Sunday Morning Jazz , later renamed Sunday Evening Jazz in early 1987. The show was hosted by Bob Craig and ended in October 1988 when Craig left the radio station. Craig returned in the spring of 1990, and again hosted a contemporary jazz show, this one running on both Saturday and Sunday nights from 7 p.m. to midnight. Along with the jazz, some soft rock songs were mixed in as well. The show lasted one year and ended in

644-402: A fax program. The original subcarrier frequency used at KE2XCC was 27.5 kHz. The IF bandwidth was ±5 kHz, as the only goal at the time was to relay AM radio-quality audio. This transmission system used 75 μs audio pre-emphasis like the main monaural audio and subsequently the multiplexed stereo audio. In the late 1950s, several systems to add stereo to FM radio were considered by

736-470: A large number of listeners, and most of them stayed with the station when it became B-101, causing WMGK to slip in the ratings. In addition, WSNI was also playing adult contemporary music, giving Philadelphia three stations in the AC format. On July 11, 1994, WMGK dropped the long time AC format and changed it to an all-1970s format. The 1970s hits included classic rock , soft rock , disco and R&B . By 1995,

828-557: A program feed for AM transmitters of AM/FM stations. SCA subcarriers are typically 67 kHz and 92 kHz. Initially the users of SCA services were private analog audio channels which could be used internally or leased, for example Muzak -type services. There were experiments with quadraphonic sound. If a station does not broadcast in stereo, everything from 23 kHz on up can be used for other services. The guard band around 19 kHz (±4 kHz) must still be maintained, so as not to trigger stereo decoders on receivers. If there

920-417: A stereo/mono switch to allow listening in mono when reception conditions are less than ideal, and most car radios are arranged to reduce the separation as the signal-to-noise ratio worsens, eventually going to mono while still indicating a stereo signal is received. As with monaural transmission, it is normal practice to apply pre-emphasis to the left and right channels before encoding and to apply de-emphasis at

1012-408: Is a form of modulation which conveys information by varying the frequency of a carrier wave ; the older amplitude modulation or AM varies the amplitude of the carrier, with its frequency remaining constant. With FM, frequency deviation from the assigned carrier frequency at any instant is directly proportional to the amplitude of the (audio) input signal, determining the instantaneous frequency of

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1104-525: Is added. VHF radio waves usually do not travel far beyond the visual horizon , so reception distances for FM stations are typically limited to 30–40 miles (50–60 km). They can also be blocked by hills and to a lesser extent by buildings. Individuals with more-sensitive receivers or specialized antenna systems, or who are located in areas with more favorable topography, may be able to receive useful FM broadcast signals at considerably greater distances. The knife edge effect can permit reception where there

1196-401: Is as follows: The normal stereo signal can be considered as switching between left and right channels at 38 kHz, appropriately band-limited. The quadraphonic signal can be considered as cycling through LF, LR, RF, RR, at 76 kHz. Early efforts to transmit discrete four-channel quadraphonic music required the use of two FM stations; one transmitting the front audio channels, the other

1288-422: Is authorized for "hybrid" mode operation, wherein both the conventional analog FM carrier and digital sideband subcarriers are transmitted. The output power of an FM broadcasting transmitter is one of the parameters that governs how far a transmission will cover. The other important parameters are the height of the transmitting antenna and the antenna gain . Transmitter powers should be carefully chosen so that

1380-460: Is claimed that no difference can be heard with most newer receivers. At present, the FCC rules do not allow this mode of stereo operation. In 1969, Louis Dorren invented the Quadraplex system of single station, discrete, compatible four-channel FM broadcasting. There are two additional subcarriers in the Quadraplex system, supplementing the single one used in standard stereo FM. The baseband layout

1472-503: Is defined by the time constant of a simple RC filter circuit. In most of the world a 50  μs time constant is used. In the Americas and South Korea , 75 μs is used. This applies to both mono and stereo transmissions. For stereo, pre-emphasis is applied to the left and right channels before multiplexing . The use of pre-emphasis becomes a problem because many forms of contemporary music contain more high-frequency energy than

1564-581: Is designed to be capable of use alongside ARI despite using identical subcarrier frequencies. In the United States and Canada , digital radio services are deployed within the FM band rather than using Eureka 147 or the Japanese standard ISDB . This in-band on-channel approach, as do all digital radio techniques, makes use of advanced compressed audio . The proprietary iBiquity system, branded as HD Radio ,

1656-429: Is limited to 30 Hz to 15 kHz to protect a 19 kHz pilot signal. The (L−R) signal, which is also limited to 15 kHz, is amplitude modulated onto a 38 kHz double-sideband suppressed-carrier (DSB-SC) signal, thus occupying 23 kHz to 53 kHz. A 19 kHz ± 2 Hz pilot tone , at exactly half the 38 kHz sub-carrier frequency and with a precise phase relationship to it, as defined by

1748-480: Is mainly the preserve of talk radio, news, sports, religious programming, ethnic (minority language) broadcasting and some types of minority interest music. This shift has transformed AM into the "alternative band" that FM once was. (Some AM stations have begun to simulcast on, or switch to, FM signals to attract younger listeners and aid reception problems in buildings, during thunderstorms, and near high-voltage wires. Some of these stations now emphasize their presence on

1840-671: Is no direct line of sight between broadcaster and receiver. The reception can vary considerably depending on the position. One example is the Učka mountain range, which makes constant reception of Italian signals from Veneto and Marche possible in a good portion of Rijeka , Croatia, despite the distance being over 200 km (125 miles). Other radio propagation effects such as tropospheric ducting and Sporadic E can occasionally allow distant stations to be intermittently received over very large distances (hundreds of miles), but cannot be relied on for commercial broadcast purposes. Good reception across

1932-742: Is often considered a separate neighborhood called Upper Roxborough. Much of the development in this area occurred after 1950, and has a suburban character: larger front lawns, garages, and shopping centers. The area of Roxborough was likely named for Roxburghshire , Scotland , the original home of Andrew Robeson, one of the first settlers of the area. In 1676, Andrew Robeson, his wife Elizabeth, and his nephew Andrew Jr. came to America from Scotland, where Andrew Sr. became Surveyor General for 300,000 acres of land in southern New Jersey, where he presided as Judge in Gloucester County . In 1690, Andrew Sr. moved to Philadelphia and purchased an estate located in

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2024-487: Is only suitable for text. A few proprietary systems are used for private communications. A variant of RDS is the North American RBDS or "smart radio" system. In Germany the analog ARI system was used prior to RDS to alert motorists that traffic announcements were broadcast (without disturbing other listeners). Plans to use ARI for other European countries led to the development of RDS as a more powerful system. RDS

2116-527: Is open to anyone who does not carry a prohibition and can put up the appropriate licensing and royalty fees. In 2010 around 450 such licences were issued. Roxborough, Philadelphia Roxborough is a neighborhood in Northwest Philadelphia , Pennsylvania , United States. It is bordered to the southwest, along the Schuylkill River , by the neighborhood of Manayunk , along the northeast by

2208-508: Is related to the transmitter 's RF power, the antenna gain , and antenna height . Interference from other stations is also a factor in some places. In the U.S, the FCC publishes curves that aid in calculation of this maximum distance as a function of signal strength at the receiving location. Computer modelling is more commonly used for this around the world. Many FM stations, especially those located in severe multipath areas, use extra audio compression /processing to keep essential sound above

2300-626: Is stereo, there will typically be a guard band between the upper limit of the DSBSC stereo signal (53 kHz) and the lower limit of any other subcarrier. Digital data services are also available. A 57 kHz subcarrier ( phase locked to the third harmonic of the stereo pilot tone) is used to carry a low-bandwidth digital Radio Data System signal, providing extra features such as station name, alternative frequency (AF), traffic data for satellite navigation systems and radio text (RT). This narrowband signal runs at only 1,187.5 bits per second , thus

2392-402: Is the sum of twice the maximum deviation and twice the maximum modulating frequency. For a transmission that includes RDS this would be 2 × 75 kHz + 2 × 60 kHz  = 270 kHz . This is also known as the necessary bandwidth . Random noise has a triangular spectral distribution in an FM system, with the effect that noise occurs predominantly at the higher audio frequencies within

2484-729: Is usually a multiple of 100 kHz. In most of South Korea , the Americas , the Philippines , and the Caribbean , only odd multiples are used. Some other countries follow this plan because of the import of vehicles, principally from the United States, with radios that can only tune to these frequencies. In some parts of Europe , Greenland , and Africa , only even multiples are used. In the United Kingdom , both odd and even are used. In Italy , multiples of 50 kHz are used. In most countries

2576-817: The FCC . Included were systems from 14 proponents including Crosby, Halstead, Electrical and Musical Industries, Ltd ( EMI ), Zenith, and General Electric. The individual systems were evaluated for their strengths and weaknesses during field tests in Uniontown, Pennsylvania , using KDKA-FM in Pittsburgh as the originating station. The Crosby system was rejected by the FCC because it was incompatible with existing subsidiary communications authorization (SCA) services which used various subcarrier frequencies including 41 and 67 kHz. Many revenue-starved FM stations used SCAs for "storecasting" and other non-broadcast purposes. The Halstead system

2668-533: The Federal Communications Commission granted WCAU Broadcasting Company a construction permit for a new FM station on 46.7 MHz on the original 42–50 MHz FM broadcast band with the W67PH call sign . The construction permit was modified on January 28, 1941, when the FCC reallocated the station to 46.9 MHz with a corresponding call sign change to W69PH. On November 24, 1941, the FCC granted

2760-502: The Lehigh Valley . On March 30, 2009, WFKB switched to Christian programming and became WBYN-FM . Currently, listeners in the northern suburbs of Philadelphia can receive WODE-FM 99.9 The Hawk , licensed to serve Easton, Pennsylvania , and primarily focused on the Lehigh Valley . In early 2006, WMGK launched a digital HD2 subchannel with its "WMGK Deep Trax" format. It features "classic rock nuggets and 'oh wow' songs that may be

2852-580: The Light Programme , Third Programme and Home Service . These three networks used the sub-band 88.0–94.6 MHz. The sub-band 94.6–97.6 MHz was later used for BBC and local commercial services. However, only when commercial broadcasting was introduced to the UK in 1973 did the use of FM pick up in Britain. With the gradual clearance of other users (notably Public Services such as police, fire and ambulance) and

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2944-567: The Wissahickon Creek section of Fairmount Park , and to the southeast by the neighborhood of East Falls . Beyond Roxborough to the northwest is Montgomery County . Roxborough's ZIP Code is 19128. Most of Roxborough is in Philadelphia's 21st Ward. The Native American trail called the Manatawny, now Ridge Avenue, was central to the well-organized development of farms and plantations within

3036-440: The baseband . This can be offset, to a limited extent, by boosting the high frequencies before transmission and reducing them by a corresponding amount in the receiver. Reducing the high audio frequencies in the receiver also reduces the high-frequency noise. These processes of boosting and then reducing certain frequencies are known as pre-emphasis and de-emphasis , respectively. The amount of pre-emphasis and de-emphasis used

3128-601: The 1930s, it was extended in 1959 from Roxborough Avenue to Andorra, and includes several concrete arch bridges. One of these bridges, the Wissahickon Memorial Bridge , which crosses over the Wissahickon Creek and Lincoln Drive, includes a pair of box tunnels under the roadway designed to carry a never built extension of the Broad Street Subway into Roxborough. Because of the Wissahickon Creek and

3220-449: The 1960s, WPEN-FM mostly simulcast 950 WPEN. In 1966, when the FCC no longer allowed most FM stations to simulcast their AM counterparts full-time, WPEN-FM carried a middle-of-the-road format, similar to the AM station, but with fewer interruptions and with mostly pre-recorded DJ comments. Some hours were still simulcast. On October 16, 1974, the station's license was voluntarily transferred by

3312-655: The 85th floor of the Empire State Building in New York City . These FM multiplex transmissions started in November 1934 and consisted of the main channel audio program and three subcarriers : a fax program, a synchronizing signal for the fax program and a telegraph order channel. These original FM multiplex subcarriers were amplitude modulated. Two musical programs, consisting of both the Red and Blue Network program feeds of

3404-617: The American Tower, stands approximately 1,250 feet (381m) tall. Public television station "MiND" , once called "WYBE", was also formerly located in Upper Roxborough, close to neighboring Andorra . The Upper Roxborough Historic District and William Levering School are listed on the National Register of Historic Places . Roxborough is well-connected to Center City Philadelphia with multiple bus routes and bike lanes reaching

3496-763: The City of Philadelphia following the passage of the Act of Consolidation, 1854 . At this time, Roxborough was the home of the area's wealthiest, the owners of the Manayunk mills. These textile mills produced revenue that was spent building schools, parks, and a large Victorian manor built for the area's elderly women, The Roxborough Home for Women. Since the 1950s, most of Philadelphia's major television and FM radio stations have located their transmission towers in Roxborough because of its hilly terrain and high elevation. The tallest of these towers,

3588-638: The FCC announced the reassignment of the FM band to 90 channels from 88–106 MHz (which was soon expanded to 100 channels from 88–108 MHz). This shift, which the AM-broadcaster RCA had pushed for, made all the Armstrong-era FM receivers useless and delayed the expansion of FM. In 1961 WEFM (in the Chicago area) and WGFM (in Schenectady, New York ) were reported as the first stereo stations. By

3680-481: The FCC that the system was compatible with existing two-channel stereo transmission and reception and that it did not interfere with adjacent stations. There were several variations on this system submitted by GE, Zenith, RCA, and Denon for testing and consideration during the National Quadraphonic Radio Committee field trials for the FCC. The original Dorren Quadraplex System outperformed all

3772-461: The FCC to Greater Philadelphia Radio, Inc., a subsidiary of Greater Media , with an effective date of January 6, 1975. On September 2, 1975, the station's call sign was changed to WMGK. The station adopted a soft rock format and changed its slogan to "Magic Music" with the Magic 103 branding. The first song aired under the new call sign was " Could It Be Magic " by Barry Manilow . The music on Magic 103

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3864-511: The FM band.) The medium wave band (known as the AM band because most stations using it employ amplitude modulation) was overcrowded in western Europe, leading to interference problems and, as a result, many MW frequencies are suitable only for speech broadcasting. Belgium , the Netherlands , Denmark and particularly Germany were among the first countries to adopt FM on a widespread scale. Among

3956-969: The FM radio band from 87.5-108.0 MHz to 76.1-108.0 MHz to enable the migration of AM radio stations in Brazilian capitals and large cities. FM broadcasting began in the late 1930s, when it was initiated by a handful of early pioneer experimental stations, including W1XOJ/W43B/WGTR (shut down in 1953) and W1XTG/ WSRS , both transmitting from Paxton, Massachusetts (now listed as Worcester, Massachusetts ); W1XSL/W1XPW/W65H/WDRC-FM/WFMQ/WHCN , Meriden, Connecticut; and W2XMN , KE2XCC , and WFMN , Alpine, New Jersey (owned by Edwin Armstrong himself, closed down upon Armstrong's death in 1954). Also of note were General Electric stations W2XDA Schenectady and W2XOY New Scotland, New York—two experimental FM transmitters on 48.5 MHz—which signed on in 1939. The two began regular programming, as W2XOY, on November 20, 1940. Over

4048-399: The FM transmitter. The terms composite , multiplex and even MPX are used interchangeably to describe this signal. The instantaneous deviation of the transmitter carrier frequency due to the stereo audio and pilot tone (at 10% modulation) is where A and B are the pre-emphasized left and right audio signals and f p {\displaystyle f_{p}} =19 kHz is

4140-712: The Middle Years (AMY) Northwest Middle School , a special admissions middle school (6–8), now occupies the building. AMY used to be located in the Mount Airy section of Philadelphia, in a rented church building. The area has been one of the main feeder regions for Roman Catholic and J.W. Hallahan High Schools . The Free Library of Philadelphia operates the Roxborough Branch at 6245 Ridge Avenue at Hermitage Street. The "Roxborough - Manayunk - Wissahickon - East Falls - Andorra Historical Society" also has an archive room in

4232-534: The NBC Radio Network, were simultaneously transmitted using the same system of subcarrier modulation as part of a studio-to-transmitter link system. In April 1935, the AM subcarriers were replaced by FM subcarriers, with much improved results. The first FM subcarrier transmissions emanating from Major Armstrong's experimental station KE2XCC at Alpine, New Jersey occurred in 1948. These transmissions consisted of two-channel audio programs, binaural audio programs and

4324-544: The Roxborough Branch. It is maintained by one of the Historical Societies' top members and one of the area's community leaders, Sylvia Myers. One of the main and oldest thoroughfares through Roxborough is Ridge Avenue . Previously a Native American trail called the Manatawny, by the 18th century the trail was known as "Ridge Road," and by the 1730s, Ridge Road was popularized as “The Great Road from Philadelphia to Reading.” Passenger stagecoaches frequently traveled on

4416-474: The Township, and Kelpius's "where foxes burrow" letter of 1706, convinced many that the township's origins related to foxes. Kelpius popularized his spelling of the township , but not long afterward the spelling was changed to its current form. The Township could have retained the names "Manatawna" or "Leverington", as they were popular names the area was referred to as in the 1690s and early 1700s, but thanks to

4508-466: The area that is known today as Roxborough, roughly where the on and off ramps for City Line Avenue and Lincoln Drive are. Andrew Jr. became Chief of Justice in Pennsylvania from 1693 until 1699. He was responsible for making Roxborough a township in 1690. The Robeson family is known to have originally come from Kelso , Roxburghshire , Scotland. Roxburgh (pronounced Rocs-burr-ah) was a small region in

4600-573: The area then known as Manatawna. The Court of Upland in England appointed local Swedish settler Peter Rambo to be the maintainer of the Manatawny road. In 1690, the road was renamed Ridge Road (it follows the crest of the ridge between the Wissahickon valley and the Schuylkill valley ), and the area was renamed Roxburgh, likely named for Roxburghshire, Scotland, the ancestral home of Andrew Robeson, one of

4692-511: The background noise for listeners, often at the expense of overall perceived sound quality. In such instances, however, this technique is often surprisingly effective in increasing the station's useful range. The first radio station to broadcast in FM in Brazil was Rádio Imprensa, which began broadcasting in Rio de Janeiro in 1955, on the 102.1 MHz frequency, founded by businesswoman Anna Khoury. Due to

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4784-403: The cluster, playing plenty of harder-edged classics, WMGK leaned softer than most classic rock stations. On November 17, 2006, at 6 p.m., former New Jersey –based classic rock station WTHK became "The New Smooth Jazz 97.5 WJJZ". With WTHK no longer airing classic rock, WMGK became the Philadelphia region's only classic rock station. The station on 97.5 is now co-owned with WMGK and carries

4876-431: The country is one of the main advantages over DAB/+ radio . This is still less than the range of AM radio waves, which because of their lower frequencies can travel as ground waves or reflect off the ionosphere , so AM radio stations can be received at hundreds (sometimes thousands) of miles. This is a property of the carrier wave's typical frequency (and power), not its mode of modulation. The range of FM transmission

4968-591: The distance between WMGK's transmitter and WQSR's transmitter is 92 miles, as determined by FCC rules. The minimum distance between two Class B stations operating on first adjacent channels according to current FCC rules is 105 miles. FM broadcasting Throughout the world, the FM broadcast band falls within the VHF part of the radio spectrum . Usually 87.5 to 108.0 MHz is used, or some portion of it, with few exceptions: The frequency of an FM broadcast station (more strictly its assigned nominal center frequency)

5060-461: The earliest settlers of the area. By 1707, the name had been changed to Roxborough. Roxborough is first mentioned as a township in QS Road Docket II: 31 in 1706. In 1840, Manayunk was erected as a borough within the township, and on March 31, 1847, Manayunk was declared separate from the township. Most of modern-day Roxborough was once part of Roxborough Township, which was incorporated into

5152-450: The early summer of 1991. Eventually, Philadelphia obtained its first full-time smooth jazz station in 1993, 106.1 WJJZ , which made its debut two years after WMGK's contemporary jazz show had ended. WUSL, the chief rival to WMGK, switched to country music in 1981. In 1989, WEAZ, an easy listening outlet known as "Easy 101", made the transition to soft AC, and in 1993, changed its call sign to WBEB , calling itself "B-101". Easy 101 had

5244-553: The extension of the FM band to 108.0 MHz between 1980 and 1995, FM expanded rapidly throughout the British Isles and effectively took over from LW and MW as the delivery platform of choice for fixed and portable domestic and vehicle-based receivers. In addition, Ofcom (previously the Radio Authority) in the UK issues on demand Restricted Service Licences on FM and also on AM (MW) for short-term local-coverage broadcasting which

5336-475: The formula below, is also generated. The pilot is transmitted at 8–10% of overall modulation level and used by the receiver to identify a stereo transmission and to regenerate the 38 kHz sub-carrier with the correct phase. The composite stereo multiplex signal contains the Main Channel (L+R), the pilot tone, and the (L−R) difference signal. This composite signal, along with any other sub-carriers, modulates

5428-482: The frequency of the pilot tone. Slight variations in the peak deviation may occur in the presence of other subcarriers or because of local regulations. Another way to look at the resulting signal is that it alternates between left and right at 38 kHz, with the phase determined by the 19 kHz pilot signal. Most stereo encoders use this switching technique to generate the 38 kHz subcarrier, but practical encoder designs need to incorporate circuitry to deal with

5520-505: The high import costs of FM radio receivers, transmissions were carried out in circuit closed to businesses and stores, which played ambient music offered by radio. Until 1976, Rádio Imprensa was the only station operating in FM in Brazil. From the second half of the 1970s onwards, FM radio stations began to become popular in Brazil, causing AM radio to gradually lose popularity. In 2021, the Brazilian Ministry of Communications expanded

5612-517: The late 1960s, FM had been adopted for broadcast of stereo "A.O.R.—' Album Oriented Rock ' Format", but it was not until 1978 that listenership to FM stations exceeded that of AM stations in North America. In most of the 70s FM was seen as highbrow radio associated with educational programming and classical music, which changed during the 1980s and 1990s when Top 40 music stations and later even country music stations largely abandoned AM for FM. Today AM

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5704-496: The late 1970s, Dolby FM was similar to Dolby B but used a modified 25 μs pre-emphasis time constant and a frequency selective companding arrangement to reduce noise. The pre-emphasis change compensates for the excess treble response that otherwise would make listening difficult for those without Dolby decoders. A similar system named High Com FM was tested in Germany between July 1979 and December 1981 by IRT . It

5796-462: The left (L) and right (R) channels are algebraically encoded into sum (L+R) and difference (L−R) signals. A mono receiver will use just the L+R signal so the listener will hear both channels through the single loudspeaker. A stereo receiver will add the difference signal to the sum signal to recover the left channel, and subtract the difference signal from the sum to recover the right channel. The (L+R) signal

5888-476: The maximum permitted carrier deviation is invariably ±75 kHz, although a little higher is permitted in the United States when SCA systems are used. For a monophonic broadcast, again the most common permitted maximum deviation is ±75 kHz. However, some countries specify a lower value for monophonic broadcasts, such as ±50 kHz. The bandwidth of an FM transmission is given by the Carson bandwidth rule which

5980-427: The maximum permitted frequency error of the unmodulated carrier is specified, which typically should be within 2 kHz of the assigned frequency. There are other unusual and obsolete FM broadcasting standards in some countries, with non-standard spacings of 1, 10, 30, 74, 500, and 300 kHz. To minimise inter-channel interference, stations operating from the same or nearby transmitter sites tend to keep to at least

6072-469: The musical styles which prevailed at the birth of FM broadcasting. Pre-emphasizing these high-frequency sounds would cause excessive deviation of the FM carrier . Modulation control (limiter) devices are used to prevent this. Systems more modern than FM broadcasting tend to use either programme-dependent variable pre-emphasis; e.g., dbx in the BTSC TV sound system, or none at all. Pre-emphasis and de-emphasis

6164-536: The next few years this station operated under the call signs W57A, W87A and WGFM, and moved to 99.5 MHz when the FM band was relocated to the 88–108 MHz portion of the radio spectrum. General Electric sold the station in the 1980s. Today this station is WRVE . Other pioneers included W2XQR/W59NY/WQXQ/WQXR-FM , New York; W47NV/WSM-FM Nashville, Tennessee (signed off in 1951); W1XER/W39B/WMNE , with studios in Boston and later Portland, Maine, but whose transmitter

6256-565: The others and was chosen as the national standard for Quadraphonic FM broadcasting in the United States. The first commercial FM station to broadcast quadraphonic program content was WIQB (now called WWWW-FM ) in Ann Arbor / Saline, Michigan under the guidance of Chief Engineer Brian Jeffrey Brown. Various attempts to add analog noise reduction to FM broadcasting were carried out in the 1970s and 1980s: A commercially unsuccessful noise reduction system used with FM radio in some countries during

6348-613: The park that protects much of its watershed , Roxborough and Manayunk are physically separated from the rest of the city. Much of lower Roxborough, consisting of "row homes" and homes dating from the 19th and early 20th centuries, has a historic, urban character. Roxborough abuts the Wissahickon Valley Park portion of the Fairmount Park system. The park's numerous trails are used by cyclists, runners, walkers, dog owners, and mountain bikers. The northwest section of Roxborough

6440-596: The popular writings of Johannes Kelpius, the name remained as Roxborough. Other spellings have also been noted in early writings as Roxbury and Roxboro. The School District of Philadelphia operates public schools. Its zoned schools include Shawmont Elementary , Cook Wissahickon , and Roxborough High School . The Walter Biddle Saul High School of Agricultural Sciences and Lankenau Environmental Magnet High School are in upper Roxborough. William Levering School, founded in 1748, closed its doors in June 2012. The Academy for

6532-528: The ratings. The station was programmed by the late Dave Klahr and signed on by its first midday host Pete Booker, who later programmed Greater Media sister station WMJC in Detroit, and who recently retired as CEO of the Delmarva Broadcasting Company . In the mid 1980s, Magic 103 leaned soft, but played several uptempo songs an hour, along with more current product. In the spring of 1986, WMGK started

6624-500: The rear channels. A breakthrough came in 1970 when KIOI ( K-101 ) in San Francisco successfully transmitted true quadraphonic sound from a single FM station using the Quadraplex system under Special Temporary Authority from the FCC . Following this experiment, a long-term test period was proposed that would permit one FM station in each of the top 25 U.S. radio markets to transmit in Quadraplex. The test results hopefully would prove to

6716-551: The reasons for this were: Public service broadcasters in Ireland and Australia were far slower at adopting FM radio than those in either North America or continental Europe . Hans Idzerda operated a broadcasting station, PCGG , at The Hague from 1919 to 1924, which employed narrow-band FM transmissions. In the United Kingdom the BBC conducted tests during the 1940s, then began FM broadcasting in 1955, with three national networks:

6808-478: The receiver after decoding. In the U.S. around 2010, using single-sideband modulation for the stereo subcarrier was proposed. It was theorized to be more spectrum-efficient and to produce a 4 dB s/n improvement at the receiver, and it was claimed that multipath distortion would be reduced as well. A handful of radio stations around the country broadcast stereo in this way, under FCC experimental authority. It may not be compatible with very old receivers, but it

6900-570: The required area is covered without causing interference to other stations further away. Practical transmitter powers range from a few milliwatts to 80 kW. As transmitter powers increase above a few kilowatts, the operating costs become high and only viable for large stations. The efficiency of larger transmitters is now better than 70% (AC power in to RF power out) for FM-only transmission. This compares to 50% before high efficiency switch-mode power supplies and LDMOS amplifiers were used. Efficiency drops dramatically if any digital HD Radio service

6992-514: The river and downtown area of Philadelphia. SEPTA's Manayunk/Norristown Regional Rail line stops in the Wissahickon section of Roxborough, continues through Manayunk, and stops again at the Ivy Ridge station in Roxborough. Philadelphia University and St. Joseph's University are nearby. Henry Avenue runs parallel to Ridge Avenue from the border of East Falls and North Philadelphia to Andorra, where it merges into Ridge Avenue. Constructed in

7084-566: The road, and many inns were built along it. Ridge Road even played a part during the American Revolution as various sections of the road were travelled by soldiers in 1777 during the lead-up to the Battle of Germantown. The other main thoroughfare through Roxborough is Henry Avenue, which was laid out in the late 1950s as a four-lane road running the length of the neighborhood and parallel to Ridge Avenue. One SEPTA Regional Rail line connects

7176-428: The sale on October 6, and the sale closed on November 1. WMGK had three major competitors in Philadelphia. On August 25, 2008, WYSP switched from active rock to classic rock, with a harder sound than that of WMGK. On September 2, 2011, WYSP switched to Sports Radio as WIP-FM . WFKB 107.5 Frank FM , licensed to serve Boyertown, Pennsylvania , competed with WMGK in Philadelphia's northern and western suburbs and in

7268-458: The southeast of Scotland until it was changed to the region of "The Borders" in 1975; the town of Kelso still remains as a historic Scottish village. In 1706, a German philosopher named Johannes Kelpius , who lived in the woods not far from the Robesons, wrote about "foxes burrowing in rocks" in the area. A correlation between the phonetic spelling "Rocksburrow" that many resident Germans applied to

7360-636: The station added a few big 1960s and 1980s hits, and no longer used the term "Magic". By the Fall of 1995, WMGK played mostly classic rock with some rock-friendly classic hits thrown in, but not much of the harder material. In 1997, Greater Media acquired two more Philadelphia FM stations, album rock WMMR and modern AC WXXM . WMGK continued to position itself as a Classic Hits station. But when WYSP changed its format from classic rock to modern rock , WMGK began to describe itself as classic rock, eliminated non-rock 1970s songs altogether. Still, with rocker WMMR in

7452-460: The station authority to begin broadcasting and granted its first license on November 18, 1942. On November 1, 1943, the station was assigned the WCAU-FM call sign. After the FCC created the current FM broadcast band on June 27, 1945, the commission granted WCAU Broadcasting the authority to begin operating the station on 102.7 MHz on December 17, 1945. The FCC granted a voluntarily reassignment of

7544-426: The station's license to Philadelphia Record Company on October 17, 1946. On June 27, 1947, the FCC reallocated the station to 102.9 MHz, followed by another voluntary reassignment of the station's license on November 28, 1947, to William Penn Broadcasting Company. This reassignment was effective on December 18, 1947, at which time the station's call sign was changed to WPEN-FM. The new owners filed an application for

7636-462: The switching harmonics. Converting the multiplex signal back into left and right audio signals is performed by a decoder, built into stereo receivers. Again, the decoder can use a switching technique to recover the left and right channels. In addition, for a given RF level at the receiver, the signal-to-noise ratio and multipath distortion for the stereo signal will be worse than for the mono receiver. For this reason many stereo FM receivers include

7728-462: The transmitted signal. Because transmitted FM signals use significantly more bandwidth than AM signals, this form of modulation is commonly used with the higher ( VHF or UHF ) frequencies used by TV , the FM broadcast band , and land mobile radio systems . The maximum frequency deviation of the carrier is usually specified and regulated by the licensing authorities in each country. For a stereo broadcast,

7820-616: Was atop the highest mountain in the northeast United States, Mount Washington , New Hampshire (shut down in 1948); and W9XAO/W55M/WTMJ-FM Milwaukee, Wisconsin (went off air in 1950). A commercial FM broadcasting band was formally established in the United States as of January 1, 1941, with the first fifteen construction permits announced on October 31, 1940. These stations primarily simulcast their AM sister stations, in addition to broadcasting lush orchestral music for stores and offices, classical music to an upmarket listenership in urban areas, and educational programming. On June 27, 1945

7912-518: Was based on the Telefunken High ;Com broadband compander system, but was never introduced commercially in FM broadcasting. Yet another system was the CX -based noise reduction system FMX implemented in some radio broadcasting stations in the United States in the 1980s. FM broadcasting has included subsidiary communications authorization (SCA) services capability since its inception, as it

8004-447: Was mostly album cuts from singer-songwriters of the 1960s and early 1970s, presented in four-song blocks with minimal talk. The station did not play artists primarily found on the Top 40 , such as The Carpenters or Anne Murray . The playlist was made up of softer songs heard on album rock stations, from artists such as Elton John , Carole King , Billy Joel , and Carly Simon . The format

8096-581: Was quite successful, with Greater Media putting "Magic Music" on its other FM stations, along with call letters referring to "Magic", WMJC in Detroit , WMJX in Boston and WMGQ in New Brunswick, New Jersey . On December 22, 1976, the FCC granted Greater Philadelphia Radio, Inc. a construction permit to relocate the station's transmitter and antenna to the Roxborough section of Philadelphia. The station's license

8188-505: Was rejected due to lack of high frequency stereo separation and reduction in the main channel signal-to-noise ratio. The GE and Zenith systems, so similar that they were considered theoretically identical, were formally approved by the FCC in April 1961 as the standard stereo FM broadcasting method in the United States and later adopted by most other countries. It is important that stereo broadcasts be compatible with mono receivers. For this reason,

8280-411: Was renewed by the FCC with the new facilities on July 12, 1978. Over time, WMGK began to lose listeners to WUSL , known as "US 1". WUSL had switched from easy listening to a soft vocal format similar to WMGK, but with a shorter playlist of more familiar songs. Eventually, WMGK responded with an even tighter playlist, moving from soft rock to a soft adult contemporary format and rebounded past WUSL in

8372-610: Was seen as another service which licensees could use to create additional income. Use of SCAs was particularly popular in the US, but much less so elsewhere. Uses for such subcarriers include radio reading services for the blind , which became common and remain so, private data transmission services (for example sending stock market information to stockbrokers or stolen credit card number denial lists to stores, ) subscription commercial-free background music services for shops, paging ("beeper") services, alternative-language programming, and providing

8464-446: Was used in the earliest days of FM broadcasting. According to a BBC report from 1946, 100 μs was originally considered in the US, but 75 μs subsequently adopted. Long before FM stereo transmission was considered, FM multiplexing of other types of audio-level information was experimented with. Edwin Armstrong, who invented FM, was the first to experiment with multiplexing, at his experimental 41 MHz station W2XDG located on

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