Does anyone have information on where the big stations broadcasted from prior to locating at Willis Tower? Did Chicago ever have a tower farm?
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Broadcast Locations before Willis Tower
- Thread starter pattywells
- Start date
FM's? Hancock if they were licensed to Chicago or any near suburb that could have a transmitter site there. If I am not mistaken, some are still there... Scott? Lance?
There. Fixed that for ya. It'll always be Sears Tower to me.
Not really, unless you consider several tall buildings around downtown a "tower farm."
The Hancock tower topped out in 1968. I do not know when the first FM began broadcasting from ther.
Just pulling a couple:
WFMT's history card is tremendously complicated, with a number of technical changes and also administrative changes and entries.
WFMT was first licensed in 1949 with call sign WOAK. It was first permitted to transmit from the roof of the Carleton Hotel, 1110 Pleasant Street, Oak Park, but I don't think they ever signed on from that site.
The first site they used was 4000 W. Washington Blvd, Chicago, atop the now-demolished Guyon Hotel.
It moved again in 1955 (to a 550 ft structure at 221 N. LaSalle St., Chicago) and but stayed at 221 LaSalle in 1960 (but upgraded to 197 kW). I believe WGN-TV was also at 221 LaSalle at this time.
WFMT requested a construction permit for to Prudential Building in 1969, signing on from the new site in autumn of '69. One year later they requested to move to John Hancock tower, and activated it in summer 1971.
It looks like they moved to the Sears Tower in 2000.
WLS-FM was first licensed in 1949. Its first site was the Civic Opera building on Lower Wacker Drive. It was moved to co-locate with WBKB-TV channel 7 in 1965 at 320 N. Dearborn and 718 ft. WLS-FM moved to John Hancock in 1971 and to the Sears Tower in 1984.
I'm surprised by the late dates for moving to the Sears Tower.
WFMT's history card is tremendously complicated, with a number of technical changes and also administrative changes and entries.
WFMT was first licensed in 1949 with call sign WOAK. It was first permitted to transmit from the roof of the Carleton Hotel, 1110 Pleasant Street, Oak Park, but I don't think they ever signed on from that site.
The first site they used was 4000 W. Washington Blvd, Chicago, atop the now-demolished Guyon Hotel.
It moved again in 1955 (to a 550 ft structure at 221 N. LaSalle St., Chicago) and but stayed at 221 LaSalle in 1960 (but upgraded to 197 kW). I believe WGN-TV was also at 221 LaSalle at this time.
WFMT requested a construction permit for to Prudential Building in 1969, signing on from the new site in autumn of '69. One year later they requested to move to John Hancock tower, and activated it in summer 1971.
It looks like they moved to the Sears Tower in 2000.
WLS-FM was first licensed in 1949. Its first site was the Civic Opera building on Lower Wacker Drive. It was moved to co-locate with WBKB-TV channel 7 in 1965 at 320 N. Dearborn and 718 ft. WLS-FM moved to John Hancock in 1971 and to the Sears Tower in 1984.
I'm surprised by the late dates for moving to the Sears Tower.
I had fun looking these up and finding all the different buildings downtown that hosted transmitters.
WBEZ (91.5): Morrison Hotel -> Marshall High School (3250 W Adams) (1949) -> Hancock Tower (1985)
WXRT (93.1): Lincoln Tower building (now Mather Tower building, 75 E Wacker Drive) -> West Town State Bank Building (2400 W Madison) (1960) -> Belmont Ave. studios (4949 W Belmont) (1971) -> Hancock (1981)
WLIT (93.9): Edgewater Beach Hotel -> Riverside Plaza (1968) -> Hancock (1971) -> Sears Tower (1974)
WLS-FM (94.7): Civic Opera House -> Marina City Tower (1965) -> Hancock (1972) -> Sears (1984)
WCHI (95.5): tower at 97th & Central in Oak Lawn -> Hancock (1971)
WBBM-FM (96.3): American National Bank Building (33 N LaSalle) -> Hancock (1971) -> Sears (1989)
WDRV (97.1): Midwest Hotel (Hamlin & Madison, Chicago) -> Civic Opera Building (1968) -> Standard Oil Building (now AON Center) (1976)
WCKL (97.9): Medinah Athletic Club building (505 N Michigan) -> Bankers Building (105 W Adams) (1945) -> Hancock (1972)
WFMT (98.7): Guyon Hotel (Pulaski & Washington) -> LaSalle-Wacker Building (221 N LaSalle) (1955) -> Prudential Building (1969) -> Hancock (1971) -> Sears (2000)
WUSN (99.5): Field Building (135 S LaSalle)-> Hancock (1972)
WSHE (100.3): Carbide & Carbon Building -> Hancock (1970)
WKQX (101.1): Civic Opera Building -> Hancock (1970)
WTMX (101.9): Skokie -> Civic Opera Building (1969) -> Hancock (1971) -> Sears (1974)
WVAZ (102.7): Oak Park Arms in Oak Park -> Hancock (1972)
WKSC (103.5): Randolph Tower (188 W Randolph) -> Sears (1974)
WBMX (104.3): Randolph Tower -> Willoughby Tower (8 S Michigan) (1958) -> Prudential (1971), Sears (1987)
WOJO (105.1): Evanston -> Hancock (1970)
WCFS (105.9): Elmwood Park -> 333 N Michigan (1966) -> Sears (1974)
WGCI (107.5): 1 N LaSalle -> Civic Opera Building (1973) -> Sears (2001)
WBEZ (91.5): Morrison Hotel -> Marshall High School (3250 W Adams) (1949) -> Hancock Tower (1985)
WXRT (93.1): Lincoln Tower building (now Mather Tower building, 75 E Wacker Drive) -> West Town State Bank Building (2400 W Madison) (1960) -> Belmont Ave. studios (4949 W Belmont) (1971) -> Hancock (1981)
WLIT (93.9): Edgewater Beach Hotel -> Riverside Plaza (1968) -> Hancock (1971) -> Sears Tower (1974)
WLS-FM (94.7): Civic Opera House -> Marina City Tower (1965) -> Hancock (1972) -> Sears (1984)
WCHI (95.5): tower at 97th & Central in Oak Lawn -> Hancock (1971)
WBBM-FM (96.3): American National Bank Building (33 N LaSalle) -> Hancock (1971) -> Sears (1989)
WDRV (97.1): Midwest Hotel (Hamlin & Madison, Chicago) -> Civic Opera Building (1968) -> Standard Oil Building (now AON Center) (1976)
WCKL (97.9): Medinah Athletic Club building (505 N Michigan) -> Bankers Building (105 W Adams) (1945) -> Hancock (1972)
WFMT (98.7): Guyon Hotel (Pulaski & Washington) -> LaSalle-Wacker Building (221 N LaSalle) (1955) -> Prudential Building (1969) -> Hancock (1971) -> Sears (2000)
WUSN (99.5): Field Building (135 S LaSalle)-> Hancock (1972)
WSHE (100.3): Carbide & Carbon Building -> Hancock (1970)
WKQX (101.1): Civic Opera Building -> Hancock (1970)
WTMX (101.9): Skokie -> Civic Opera Building (1969) -> Hancock (1971) -> Sears (1974)
WVAZ (102.7): Oak Park Arms in Oak Park -> Hancock (1972)
WKSC (103.5): Randolph Tower (188 W Randolph) -> Sears (1974)
WBMX (104.3): Randolph Tower -> Willoughby Tower (8 S Michigan) (1958) -> Prudential (1971), Sears (1987)
WOJO (105.1): Evanston -> Hancock (1970)
WCFS (105.9): Elmwood Park -> 333 N Michigan (1966) -> Sears (1974)
WGCI (107.5): 1 N LaSalle -> Civic Opera Building (1973) -> Sears (2001)
WXRT (And the rest of Audacy's FMs) still have a backup facility at the Belmont building. They turn them on when work is being done on the Sears Tower. Some of them are in HD.
WGCI still has a backup on the Civic Opera Building for the same reason.
WLIT and WLS-FM also have Aux sites at the Hancock
WGCI still has a backup on the Civic Opera Building for the same reason.
WLIT and WLS-FM also have Aux sites at the Hancock
Wow good work everyone!
I figured they just kept moving from one tall building to the next.
And yes, everyone still calls it the Sears Tower - what was I thinking!
I figured they just kept moving from one tall building to the next.
And yes, everyone still calls it the Sears Tower - what was I thinking!
Some say it's the "What You Talkin' About Willis" Building.
Google it. A lot of people still call it the Sears Tower.
Here we go.
WEAW-FM 105.1 was on one of the earlier WEAW 1330 nondirectional towers in Evanston. It was 180000 watts from a very low HAAT as I recall.
Google it. A lot of people still call it the Sears Tower.
Here we go.
WEAW-FM 105.1 was on one of the earlier WEAW 1330 nondirectional towers in Evanston. It was 180000 watts from a very low HAAT as I recall.
The WEAW Towers are still an entry in the geographical database.
The tower does not correspond to the address on the FCC History Card, however. That is 2425 Main Street, Evanston,IL. Maybe that's the driveway access postal address.
WEAW-FM was 180000 watts from 240 feet HAAT. I don't know if that would meet RF exposure limits at ground level today.
Trying to make sense of the History Card for WEAW 1330, it looks like it was always DA-D, even with 500 watts. The application to move to Dundee Rd. says it uses 3 additional towers, so I would assume it had 3 towers in the DA at the 2425 Main Street postal address. It looks like a taller tower was built for WEAW-FM 105.1. The towers were apparently actually a block or two North of the Studio and or driveway at 2425 Main Street. The taller tapered self supporting tower is apparently still there, according to a picture I saw somewhere.
mapcarta.com
The tower does not correspond to the address on the FCC History Card, however. That is 2425 Main Street, Evanston,IL. Maybe that's the driveway access postal address.
WEAW-FM was 180000 watts from 240 feet HAAT. I don't know if that would meet RF exposure limits at ground level today.
Trying to make sense of the History Card for WEAW 1330, it looks like it was always DA-D, even with 500 watts. The application to move to Dundee Rd. says it uses 3 additional towers, so I would assume it had 3 towers in the DA at the 2425 Main Street postal address. It looks like a taller tower was built for WEAW-FM 105.1. The towers were apparently actually a block or two North of the Studio and or driveway at 2425 Main Street. The taller tapered self supporting tower is apparently still there, according to a picture I saw somewhere.
WEAW Radio Towers
WEAW Radio Towers is a tower in Evanston, Cook, Illinois. Mapcarta, the open map.
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It looks like the tower at 2425 Main St. was shortened or moved behind the building.
I would have loved to talk to Glen Clark, Jeremy Ruck, and Charlie Gustafson about this subject. I had talked to the three of them on the phone and emailed them a number of times. I was greatly saddened when they all passed away. Charlie almost had a a job at WEAW, he worked at WTAQ, WCFL, and WIND as an engineer. Glen Clark was CE at WLS-FM and a staff engineer at WLS. Jeremy Ruck played an important role in managing the massive Willis Tower transmitting facilities, and an FM TL move and upgrade in Michigan I worked on with him on with the late Bill Sanderson, which many in the industry said couldn't be done, and tried twice to block it with Petitions to Deny. Eventually, we accomplished a substantial upgrade, though with all the Petitions, not as much of an improvement as it could have been. That always bothered me. I miss them all greatly.
I would have loved to talk to Glen Clark, Jeremy Ruck, and Charlie Gustafson about this subject. I had talked to the three of them on the phone and emailed them a number of times. I was greatly saddened when they all passed away. Charlie almost had a a job at WEAW, he worked at WTAQ, WCFL, and WIND as an engineer. Glen Clark was CE at WLS-FM and a staff engineer at WLS. Jeremy Ruck played an important role in managing the massive Willis Tower transmitting facilities, and an FM TL move and upgrade in Michigan I worked on with him on with the late Bill Sanderson, which many in the industry said couldn't be done, and tried twice to block it with Petitions to Deny. Eventually, we accomplished a substantial upgrade, though with all the Petitions, not as much of an improvement as it could have been. That always bothered me. I miss them all greatly.
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You might find it interesting that the original FM combiner a the Hancock center, designed by Andrew Alford, was a massive “comb filter” system comprised delay lines and hybrids. While reliable for many years, it was suspected that the passband response it provided to each station had certain negative effects on reception and demodulated audio quality.
The original system was replaced in the late 1980s with a new 10-station band-pass combiner manufactured by Shively Labs. The system is unique in that the specifications were based on minimizing it's impact on reception and demodulated audio. This was accomplished by control of passband phase response for minimum distortion and maximum stereo performance of the demodulated signal, and by minimizing passband ripple, which in turn minimized synchronous AM, and resulted in lower muitipath distortion. In short, it was the first (and likely the only) combiner specified based on received audio performance for a 10 station system with 8 of the 10 stations spaced by only 800KHz.
Research to develop the specifications was conducted by members of the Hancock FM Committee using “FM SIM”, an FM simulation software package written by Dave Herschberger. It provided a theoretically perfect stereo generator and FM transmitter, then a perfect demodulator with stereo demod, between which could be inserted models of various filters. Simulations were conducted that modeled amplitude response, group delay and phase response, bandwidth and slopes, then plotted the resulting changes in audio parameters such as distortion and channel separation. Then, in-field research was conducted on the impact of non-flat amplitude response in a multipath environment to determine the maximum tolerable pass-band ripple. The results became the target specifications for each station’s filter and resulting pass-band.
Several combiner manufacturers agreed that the specs were “crazy” and unnecessarily stringent, one stating flat out that he "knew" that less than 0.1dB of passband ripple was "completely unnecessary". His company refused to bid on the project. Shively, however, not only bid, and agreed to produce a system that met the specifications, but was awarded the project. The results after field tuning were extremely close to the original specifications, and for several ports, even exceeded them.
The original system was replaced in the late 1980s with a new 10-station band-pass combiner manufactured by Shively Labs. The system is unique in that the specifications were based on minimizing it's impact on reception and demodulated audio. This was accomplished by control of passband phase response for minimum distortion and maximum stereo performance of the demodulated signal, and by minimizing passband ripple, which in turn minimized synchronous AM, and resulted in lower muitipath distortion. In short, it was the first (and likely the only) combiner specified based on received audio performance for a 10 station system with 8 of the 10 stations spaced by only 800KHz.
Research to develop the specifications was conducted by members of the Hancock FM Committee using “FM SIM”, an FM simulation software package written by Dave Herschberger. It provided a theoretically perfect stereo generator and FM transmitter, then a perfect demodulator with stereo demod, between which could be inserted models of various filters. Simulations were conducted that modeled amplitude response, group delay and phase response, bandwidth and slopes, then plotted the resulting changes in audio parameters such as distortion and channel separation. Then, in-field research was conducted on the impact of non-flat amplitude response in a multipath environment to determine the maximum tolerable pass-band ripple. The results became the target specifications for each station’s filter and resulting pass-band.
Several combiner manufacturers agreed that the specs were “crazy” and unnecessarily stringent, one stating flat out that he "knew" that less than 0.1dB of passband ripple was "completely unnecessary". His company refused to bid on the project. Shively, however, not only bid, and agreed to produce a system that met the specifications, but was awarded the project. The results after field tuning were extremely close to the original specifications, and for several ports, even exceeded them.
WFMT is still a grandfathered superpower FM, even though it is now just 6000 watts ERP. This is because it has an HAAT a lot higher at that ERP than would be permitted under current rules. Grandfathered Superpower FM station change restrictions fall under CFR 47 Section 73.211.
www.law.cornell.edu
47 CFR § 73.211 - Power and antenna height requirements.
A lot of extra detail is provided for applications, CPs, and licenses for both AM and FM around Chicago, manually entered from History Cards. Many older stations also show enhanced History on fccdata.org and fccinfo.com. The records are not identical, but complement each other.
WFMT was 15.5kW at 1173.5 ft at Hancock, 6kW at 1509ft at Sears/Willis.
From 1960 to 1965 there were various power levels between 120kW to 197kW at 550ft. Hence the grandfathering.
From 1960 to 1965 there were various power levels between 120kW to 197kW at 550ft. Hence the grandfathering.
I noticed there were several stations at the Civic Opera House in the past. Was there a large tower on top of the structure at one time and did they use a combiner and one antenna?
The Civic Opera House is (according to the reputable folks on Wikipedia) 550’ tall…back in the pre-high rise days, 550’ (plus a couple dozen feet for the tower) would have been pretty adequate to cover Chicago as a class B.
From memory...it was just WGCI for many years, and is still their backup site (main is Willis). I think the mast on the Opera House may have taken the center of radiation close to 600'. If there was another, you'd have to look back 50 years or more.
Also, from memory, there is only one combiner in Chicago. There are lots of co-located individual antennas with filters.
Thanx
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