By David - K3DAV
Here is one good example of how digital TV has improved the technology in our favor. Digital stations can now deliver more than one channel of programming on the same channel. They are called subchannels or multi-channels. A subchannel is an additional channel(s) of programming that can be sent within the same digital bit-stream as the original main channel. The old analog transmission used a carrier wave to send a very wide carrier filled with several modulated waves at different frequencies to transmit a video signal.
How Do They Do It?
But how do they send a subchannel now we have digital. Digital TV uses the same language that your computer uses. It's called "Binary". Binary is a series of millions of codes made up of ones and zeros. The analog video and audio are converted to digital binary codes, then transmitted over the air in pulses called "Packet Bursts". These pulses are received by your TV which converts those ones and zeros back to analog so the video can be displayed on your Screen.
Binary codes are sent in what we call a bit-stream. Think of a bit-stream as water running down a river. At the end of the river the water gets divided up and sent into thousands of smaller hoses that send water to different places. This is a similar way that a digital bit-stream works. All of the information of the video and audio are sent together as one big bit-stream. But each of the bits are coded for their specific task. Some of the bits are coded for color, some for size, some for placement in a picture, some just for the left stereo sound channel, and some for the right...etc.. But there is one code that specifies the stream as a single audio and video programming channel. The codes tell your TV circuitry what to do with each bit of data info.
The binary coding takes up far less frequency spectrum than than the old analog video and audio signals used. This means they can now send a lot more data information within the same channel space. So now your local TV station can transmit several bit-streams of data side by side with each other within the same channel space. Your TV's circuitry decodes the bit-streams and separates the proper ones and zeros for each program, and displays it on your Screen as a channel. Digital satellite services like DirecTV and DISH have been transmitting all of their channels using the binary system since they first began.
Channels Are Now Virtual Channels
A "Channel" is not the same as it used to be. An analog channel was a transmitted carrier on a specific set of assigned frequencies called channels. But today, a bitstream can be sent on any frequency and digitally tagged with any channel number to make it easy for us little humans to understand. So when you tune to channel 8 on your digital TV, cable box, or satellite box, the receiver is picking out the bit-stream that the provider encoded with the number "8" to make it easy for you to remember. This is done with "Virtual Channel Labeling". The provider can assign any channel number to any program bit-stream. So when you want to see that station, you must enter in the number they assigned to it. If they want to move channel 8 to another channel on your box, all they need to do is change the assigned virtual channel number associated with channel 8, and it will now appear on the new assigned virtual channel number. They haven't really moved the station to a new frequency or connection in their system. They just gave that particular bit-stream a brand new channel ID code for you to find them at.
Throughout the many decades of analog TV, we had just 7 stations in my area to watch. But now, because of the new digital TV technology, those same 7 stations are giving us 15 channels of programming. Below is an example list of local Digital TV stations and their subchannels. For this example, we will use the Harrisburg market which includes Harrisburg, Lancaster, Lebanon, and York, PA markets. They are the channels in my viewing region. And for our local visitors to this page, I have added a quick history to each station listing.
A special note: Back when stations still had analog transmitters turned on, they had to start transmitting their digital signals on a different channel. The digital and analog signals can not exist together on the same frequency space. Back in June 2009 when the analog transmitters had to be shut down forever, many stations across the country, moved their digital signal back to their old analog channel space. But some stations did not make the move for various legal reasons. A station can label their channel number on your TV's tuner, to display any number they want, even though they may not be on that actual channel number.
For example, notice below that Channel 15 WLYH is identified on your TV as being on channel 15.1 (Virtual Channel), but they are actually transmitting on channel 23 (Actual Channel). In other words, your TV will scan and find WLYH on digital channel 23, but your on-screen display will indicate that you are on channel 15.1 . This is normal, and called "Virtual Channel Labeling". The station has full control of this feature and it is all done for your convenience. Once your TV has scanned and found all of the channels in your area, you will then be able to access them using their old channel numbers. You can go to channel 15 by just entering 15-1 on your remote, even though they are actually on channel 23.
Your local cable company does the same thing. They may have several of your local channels on 1 or 2 actual digital channels, but they use Virtual Channel Labeling to make that station appear on any cable box channel number they choose for your convenience. For example, in Harrisburg, PA, Comcast Cable has WGAL-8 in HD and WHTM-27 in HD along with both station's subchannels all on digital cable channel 58. But Comcast uses Virtual Channel Labeling to make WGAL-8 appear on channel 808, and WHTM-27 appear on 807 on your cable converter box. Their subchannels are virtually labeled to appear on channel numbers in the 200's. But all 5 of these channels are actually on digital cable channel 58.
In this TV market, stations WGAL-8 and WHP-21 are the only channels that have moved their digital transmitters over to their original channels. The rest are still on their original digital channel. This is noted next to the station logos below.
We also list their power outputs. For example, WHP 21 is listed below with a power output of 14.35KW (TX) @ 450 KW (ERP). This means that their transmitter is sending 14,350 watts to the antenna. But the high dB gain factor of their antenna multiplies that power and emits an Effective Radiated Power (ERP) of 450,000 watts, from the antenna. Transmitters on VHF channels 2 - 13, require less power than UHF channels 14 - 50, to reach the same distance. Channels 8 on DTV 8, and 27 on DTV 10, are both on VHF channels. The rest are on UHF and use more power.
A special note: The source used for the technical station information in this article, is a website called RABBIT EARS. They are a top source for up to date technical information on digital stations around the country. You can use Rabbit Ears to find the list of TV stations in your local market, including their subchannels and all of the technical data for them.
Clicking on any of the station logos below, will open a link to their website.
WGAL-HD Channel 8.1 (1080i) NBC HD television network, and local news. From Lancaster, PA. Power output: 6KW (TX) @ 59KW (ERP).
WGAL-DT Channel 8.2 (480i) "THIS" TV network (Classic Movies and TV Shows), from the MGM film studios.
For residents within a 15 mile radious from the Harrisburg city area. WGAL also transmits a lower powered signal on digital channel 49 from a tower on Blue Mountain, on the northern edge of Harrisburg PA. It is for Harrisburg area viewers who may have a difficult time receiving WGAL channel 8's signal from their main transmitter in Hallem, York County. Both WGAL in HD and their subchannel "THIS" network in SD are carried on this low power transmitter. When your TV scans and finds WGAL on channel 49, it will automatically label the two channels as 8.1 and 8.2, even though they are actually on digital channel 49. Below is the tech info for the transmitter in Harrisburg, PA.
WGAL-HD Channel 49.3 (8.1) (1080i) NBC HD television network, and local news. From Lancaster, PA. Power output: 2.16KW (TX) @ 15 KW (ERP). Tower is on Blue Mountain in Harrisburg, PA
WGAL-DT Channel 49.4 (8.2) (480i) "THIS" TV network (Classic Movies and TV Shows), from the MGM film studios.
History: WGAL TV went on the air on March 18, 1949 on channel 4. They were owned by the Steinman Family and carried programming from NBC TV Network. They also carried some of the old DuMont TV network and ABC and CBS programs as well until 1963. On December 31, 1952 when WGAL raised their power, they were ordered by the FCC to move to their current channel 8. This move was to pervent interference to WRC TV 4 in Wash DC. On January 1 1954, WGAL became the first PA station to broadcast in color with NBC programming. In late 1978, the Steinman family sold WGAL to Pulitizer Broadcasting. In 1985, WGAL became the first station in PA to broadcast stereo sound. On March 18, 1999, Pulitizer sold WGAL to the current owner, Hearst-Argyle Television. Later in the same year, WGAL began transmitting it's new digital HDTV channel on UHF channel 58. On June 12, 2009, WGAL finally shut down it's analog transmitter on channel 8, and moved it's HD channel from 58 to their original channel 8. On August 29, 2011. WGAL became the second station in the market to begin broadcasting local news and commercials in full 1080i HDTV. But there is one exception. Their news field reporters still use standard definition (480i) equipment, but it is presented in 16:9 widescreen.
WLYH HD Channel 15.1 (1080i) The CW HD TV network, Phillies baseball, and local news. From Lebanon, PA. Power output: 20KW (TX) @ 500KW (ERP).
WLYH-DT Channel 15.2 (480i) Live Well Network.
History: WLYH went on the air as an indipendent station on October 25, 1953 with the call sign WLBR on UHF channel 15. It was owned by Lebanon Television Corporation. In October 1954, Hurricane Hazel took the station off the air for a long time. In 1957, Triangle Publications bought up the WLBR license and put the station back on the air as a part time ABC affiliate. On January 1, 1959, WLBR became the current WLYH, and later in 1961 became a CBS affiliate. In 1971, Triangle sold the station to Gateway Communications. On January 16, 1995, WLYH took on the new UPN network as a secondary affiliate to CBS. In the Fall of 1995, Clear Channel Communications who just pruchased WHP TV 21, also a CBS affiliate, signed a 20 year local marketing agreement with Gateway to take operating control of WLYH. As WHP took control of WLYH, they made WLYH a primary UPN affiliate dropping CBS after 34 years. WHP was now the only CBS affiliate in the market, and WLYH, (now a sister station of and operated by WHP), was a full time UPN station as of December 16, 1995. In 2000, Gateway sold WLYH to SJB Communications. On September 18, 2006, UPN, and the WB Networks went under, and spawned 2 new networks called the CW, and My Network TV. WLYH became the new CW affiliate, and WHP adopted My Network TV for their secondary digital subchannel on 21.2. In late 2006 a company called Nexstar purchased WLYH from SBJ, but still under the operation of WHP. WLYH began broadcasting it's new digital HDTV transmitter on channel 23. On February 17, 2009, WLYH shut down their analog transmitter on channel 15, but their digital HDTV transmitter remains on channel 23 under the digital ID of channel 15. WLYH still broadcast their local programs in the old 4:3 standard definition format. But they broadcast all of their CW network shows and certain sports events like the Phillies Baseball, PA football games, and now the CBS-21 news from sister station WHP in 1080i HD as of 4/14/2012. It is not known when they will convert their studio to broadcast the rest of their local shows in HD.
WHP-HD Channel 21.1 (1080i) CBS HD television network, and local news. In Harrisburg, PA Power output: 28.84KW (TX) @ 750KW (ERP).
WHP-DT Channel 21.2 (480i) "My Network TV" (Nicknamed "My Twenty One two").
History: WHP went on the air on July 4th, of 1953 on UHF channel 55. They began as an affiliate of both the CBS and DuMont networks. Commonwealth Communications was the original owner, and when the DuMont network went dark in 1956, WHP stayed with their CBS affiliation. In 1957, WHP moved from channel 55 to their current channel 21 position. Commonwealth sold WHP to Clear Channel Communications in 1995. Around this same time, WHP took operations control of WLYH with their studios now located at the WHP studio location in Harrisburg PA. In 2003, WHP began broadcasting their digital HDTV signal on VHF channel 4. On September 5, 2006, WHP launched a digital subchannel on 21.2 to be the areas My Network TV affiliate. In April 2007, Clear Channel sold all of their TV stations to Newport Television. In December 2012, Newport sold WHP to (SBG) Sinclair Broadcast Group, the current owner-operator. On June 12, 2009, WHP finally shut down their analog transmitter on channel 21, and moved their digital HD channel from channel 4 to their original and current UHF channel 21. WHP currently still broadcast their local syndicated shows, and commercials in a 4:3 Standard Definition format on their HDTV channel. But their programming from CBS is always in full 1080i HD. And as of 4/14/2012, WHP began broadcasting their local "CBS21" newscast in full 1080i HD. It is not known when they might convert their local studios to broadcast the rest of their local syndicated shows in 1080i HD.
WHTM-HD Channel 27.1 (720p) ABC HD television network, and local news in HD. From Harrisburg, PA. Power output: 1.68KW (TX) @ 16.2KW (ERP).
WHTM-DT Channel 27.2 (480i) RTV network. (Retro TV). Classic TV shows.
WHTM-DT Channel 27.3 (480i) ABC27 Weather Now. Combines Accu-weather & WHTM local weather reports.
History: This channel number has an odd past in Harrisburg PA. There originally was a TV station on channel 27 with the calls of WCMB. They were a DuMont affiliate that went on the air in September 8, 1954, and quickly off the air on April 9, 1957, shortly after the DuMont Network went dark forever in late 1956. But this station has no connection to WHTM.
WHTM went on the air on June 19, 1953 as WTPA, an NBC affiliate on UHF channel 71. They were owned by their founders, the Newhouse Family which later became Advance Publications. In 1957, WTPA bought the off the air WCMB station on channel 27, and used some of the old WCMB equipment. This was when WTPA moved from channel 71 to channel 27 and switched from NBC to a full time ABC network affiliate. In 1980, the Times Mirror Company aquired all of the Newhouse TV stations including WTPA, and changed the call sign to the current WHTM. Times Mirror sold WHTM to Smith Broadcasting in 1986. Then it was sold to Price Communications in 1994. Then it was sold one last time to Allbritton Communications in 1996. But as of July 30, 2013, Sinclair Broadcasting has aquired Allbritton Communications and all of the stations, making Sinclair Broadcasting the new owner of WHTM.
WHTM began transmitting it's new digital HD channel on VHF channel 10 in 1999. On June 12, 2009, WHTM shut down their analog transmitter on channel 27 forever. They currently continue to broadcast their 720p HDTV programming on VHF channel 10. It is not known if they will ever move back to their original UHF channel 27 frequency or not. But they continue to identify as being channel 27. On October 14, 2011, WHTM became the third area station to broadcast all local news, syndicated shows, and commercials in full 720p High Definition and 16:9 widescreen.
WTIF-HD Channel 33.1 (1080i) PBS HD television network from Harrisburg, PA.
Power output: 1.9KW (TX) @ 50KW (ERP).
History: Channel 33 began as WEEU-TV, a commercial television station licensed to Reading in the 1950s. The station failed after the Philadelphia stations boosted their signals to cover Reading, and the channel was reallocated to the Harrisburg area for Non-commercial educational use. The South Central Educational Broadcasting Council was formed in 1963, and it quickly snapped up the channel 33 license. WITF-TV signed on for the first time on November 22, 1964 from "temporary" studios in Hershey, near the Hershey Theatre. In 1982, it moved to studios in northeast Harrisburg. In 2007, it moved to its first-ever purpose-built high tech home in Swatara Township. In 1998, WITF-TV made history in Pennsylvania by launching the Commonwealth's first digital television channel on channel 36. WITF was offering the "PBS-HD channel" on channel 33.3, however, that channel no longer exists since February 17, 2009 when WITF shut down their analog transmitter on channel 33. PBS HD was a lot like the Discovery Channel, History Channel, and the Travel channel combined. It was designed to show off the beauty of high definition to new HD set owners. WITF's digital HD channel is still located on UHF channel 36 but now carries the regular PBS programming. It is not known if they will eventually move their digital station back to the original channel 33 position or not. As broadcasters across the country were switching from 50-year old analog technology to the federally mandated digital format, WITF became one of the first in the nation to meet the technological, financial and educational challenges.
In 1998, WITF-TV made history in Pennsylvania by launching the Commonwealth's first digital television channel on channel 36. WITF was offering the "PBS-HD channel" on channel 33.3, however, that channel no longer exists since February 17, 2009 when WITF shut down their analog transmitter on channel 33. PBS HD was a lot like the Discovery Channel, History Channel, and the Travel channel combined. It was designed to show off the beauty of high definition to new HD set owners. WITF's digital HD channel is still located on UHF channel 36 but now carries the regular PBS programming. It is not known if they will eventually move their digital station back to the original channel 33 position or not. As broadcasters across the country were switching from 50-year old analog technology to the federally mandated digital format, WITF became one of the first in the nation to meet the technological, financial and educational challenges.
WPMT-HD Channel 43.1 (720p) FOX TV HD network, and local news. Located in York, PA Power output: 20.2KW (TX) @ 933KW (ERP).
WPMT-DT Channel 43.2 (480i) Antenna TV -- (Classic TV shows from the "antenna" days)
WPMT-DT Channel 43.3 (480i) Fox43 News 24/7
History: WPMT began broadcasting on December 21, 1952 as WSBA-TV. It was owned by Susquehanna Radio Corporation along with WSBA-AM 910. It was one of the first commercially licensed UHF stations in the United States. WSBA was originally an ABC affiliate. However, in 1961, the station switched to CBS and joined the Keystone Network which comprised WHP-TV in Harrisburg and WLYH-TV in Lebanon. The three stations provided a strong combined signal with about 55% overlap. Initially, WHP-TV, WLYH and WSBA aired the same programming. In May 1983, Susquehanna sold WSBA-TV to Idaho-based Mohawk Broadcasting, who changed its calls to the current WPMT. In 1983, the station signed off in August and returned to the air in September as an independent station. The first in the state outside Philadelphia and Pittsburgh. It was a typical UHF independent airing cartoons, sitcoms, movies, dramas, sports, and westerns. On October 6, 1986 after Mohawk sold the station to Renaissance Broadcasting, it became one of the charter affiliates of the newly-launched Fox network. In 1997, Renaissance merged with Tribune Broadcasting, WPMT's present owner. WPMT shut down its analog transmitter on June 12, 2009, and remained on its current digital channel 47, but continues to identify as channel 43. It is not known if they will ever move back to their original channel 43 position or not. On January 15, 2011, WPMT became the first station in Central Pennsylvania and the last Tribune-owned Fox-affiliated station to broadcast local news in full 720p high definition.
WGCB-HD Channel 49.1 (720p) This channel is a part time provider of the "MeTV Network" which shows classic TV programming, but unfortunately they do not show ALL of the MeTV programs. The rest of WGCB programming is God TV, Pray TV, send us money so we can pray more for you TV. From Red Lion, PA. Power output: 23.44KW (TX) @ 500KW (ERP).
WGCB-DT Channel 49.2 (480i) MeTV Network. Classic TV shows 24/7. Unfortunately, this subchannel is not carried by Cable systems in the area. And WGCB is a weak station and can not be seen by most people in this area. So only a few people near the WGCB transmitter can watch MeTV.
History: WGCB-TV went on the air on April 28, 1979. It is an independent station producing mainly Christian programs. It is also affiliated with Me-TV. John Harden Norris, joined his father in establishing Red Lion Broadcasting, the original owner of WGCB. Mr. Norris died September 28, 2008 at the age of 82. The FCC granted a change in control for WGCB on November 5, 2008 to the Estate of John H. Norris, Anna L. Plourde-Norris, Executrix, the stations current owner-operator. Previously, the channel 49 frequency in the Susquehanna Valley region was occupied by WNOW-TV, which was located in York and was originally affiliated with the DuMont Television Network, and later the NTA Film Network. But it could not compete with WGAL-TV and eventually went off the air. WGCB's studio and transmitter are located in Red Lion. Their broadcast tower is small and located next to their studios in the town. This makes WGCB a very weak signal to most of it's regional market. They recently began to carry the MeTV network on their digital subchannel, 49.2. But only viewers close by the station can see it. Most of the regions cable systems carry WGCB's main (49.1) channel, but they do not carry the (49.2) MeTV subchannel. So unless you live close to the station and use an antenna, MeTV programming is not available to most of the market. They should move their transmitter and tower to a much higher location to cover beyond the many mountains in the region. In 2009, WGCB shut down their analog transmitter on channel 49, and continues to broadcast a digital signal on channel 30. WGCB began broadcasting in 720p HD in September 2012, and was just purchased by Titan Broadcast Management. Hopefully the new owners will put some money into this station and move the transmitter to a much higher location so people 20 miles away can see them.
Previously, the channel 49 frequency in the Susquehanna Valley region was occupied by WNOW-TV, which was located in York and was originally affiliated with the DuMont Television Network, and later the NTA Film Network. But it could not compete with WGAL-TV and eventually went off the air.
WGCB's studio and transmitter are located in Red Lion. Their broadcast tower is small and located next to their studios in the town. This makes WGCB a very weak signal to most of it's regional market. They recently began to carry the MeTV network on their digital subchannel, 49.2. But only viewers close by the station can see it. Most of the regions cable systems carry WGCB's main (49.1) channel, but they do not carry the (49.2) MeTV subchannel. So unless you live close to the station and use an antenna, MeTV programming is not available to most of the market. They should move their transmitter and tower to a much higher location to cover beyond the many mountains in the region.
In 2009, WGCB shut down their analog transmitter on channel 49, and continues to broadcast a digital signal on channel 30. WGCB began broadcasting in 720p HD in September 2012, and was just purchased by Titan Broadcast Management. Hopefully the new owners will put some money into this station and move the transmitter to a much higher location so people 20 miles away can see them.