The Old CATV Equipment Museum
CATV Off-Air Signal Reception
VHF/UHF Broadcast Television Receiving Antennas in situ
This page describes several VHF/UHF receiving antenna structures. In general, the antennas are presented in order of increasing distance from the originating broadcast antenna.
Town of Middleton, Dane County, Wisconsin
Communication Technologies, Inc.
Photo: Neal McLain
Photo: SBE 24
This headend building (left), located in the Town of Middleton, is located less than two miles from the Madison Community Tower (right), a 1420-foot candelabra structure located near Madison. The tower supports numerous antennas including several television broadcast antennas on the candelabra platform at the top. Note that the uppermost receiving antenna on the building mast (a UHF yagi) is actually tilted upward by about 9° to aim it toward the transmitting antennas.
These antennas — and the entire headend, building and all — were removed in the late 1990s after the cable TV system was sold.
The Town of Middleton (as well as the adjoining City of Middleton) are located in Dane County, which is located in the Madison DMA.
Photo of Madison Community Tower courtesy of Society of Broadcast Engineers, Chapter 24, Madison, Wisconsin.
Hillsdale, Hillsdale County, Michigan
Photos: Neal McLain
This tall tower (about 1000 feet) is capable of receiving signals from six directions.
These photos illustrate the historic significance of receiving distant broadcast stations. Before the rise of satellite-delivered non-broadcast television programming in the late 1970s, cable TV offerings were limited to retransmission of broadcast television stations or locally-originated programming. Many cable TV companies built tall towers to receive independent stations from distant locations.
Since the rise of satellite-delivered non-broadcast television programming, distant broadcast stations have become far less important to the industry.
Most of the antennas shown in these photos were installed before 1975. Many of them had already been abandoned by 1982, when these photos were taken, and may have been removed since then.
Hillsdale is located in Hillsdale County, which is in the Lansing DMA. Stations licensed to Lansing and Jackson are transmitted from Onondaga, a community between Lansing and Jackson.
Antennas on this tower could receive stations from five foreign DMAs plus Canada:
South Bend-Elkhart-Benton Harbor
Grand Rapids-Kalamazoo-Battle Creek
Windsor, Ontario (in particular, CBET, formerly CKLW-TV).
Las Cruces, Doņa Ana County, New Mexico
Photos: Neal McLain
This tower receives television signals from El Paso, about 45 miles south. Note the quad-array antenna for low-band VHF reception and the solid parabolic reflector for UHF reception.
Las Cruces is located Doņa Ana County NM, which is in the El Paso DMA.
Decorah, Winneshiek County, Iowa
Teleview Systems Corporation
Photo: Neal McLain
This tower receives television signals from Waterloo, Iowa, about 66 miles southwest. This is a unique tower: it's a former AM Radio Transmission Tower. When used for radio service, the entire tower was insulated from ground; after Teleview Systems began using it as a receiving antenna, the tower was grounded. This tower was destroyed by a severe windstorm in the 1990s.
Decorah is located in Winneshiek County, which is in the Cedar Rapids - Waterloo - Dubuque DMA.
Vero Beach, Indian River County, Florida
United Artists Cable
This tower receives television signals from Melbourne, Orlando, and West Palm Beach, Florida. The tower supports quad-array VHF antennas aimed north (Orlando, 71 miles) and south (West Palm Beach, 66 miles).
The tower also supports a "search antenna" at the top, above all other antennas. A search antenna is a high-gain broadband yagi controlled by a rotor so that it can be aimed in any direction. Search antennas were useful for several applications:
Emergency backup: A temporary substitute for another antenna.
Testing: A tool for evaluating the technical quality of arriving broadcast signals.
Network Restoration: Reception of foreign-DMA network programming to supplement home-DMA non-network programming. Under FCC rules in force before the effective date of the 1992 Cable Act, a cable television company could restore network programming not cleared by its home-DMA affiliate if it could import the missing network programming from a foreign-DMA network affiliate. The restored programming was carried in a separate channel; the home-DMA station's signal was carried on its normal channel without alteration.
Cherrypicking: Reception of distant-station programming (network or otherwise) on a program-by-program basis. Under FCC rules in force during the 1950s and 60s, a cable TV company could "cheerypick" distant-station programming of interest to local audiences (for example, an "away game" sports event).
Vero Beach is located in Indian River County, which is located in the West Palm Beach - Ft. Pierce DMA. Indian River County is located at the northern boundary of its DMA, adjacent to the Orlando - Daytona Beach - Melbourne DMA. Thus, Melbourne and Orlando stations for foreign-DMA stations with respect to Vero Beach.
Cressey, Merced County, California
General Electric Cablevision
This unusual VHF receiving antenna is located near Cressey, California, about 15 miles northwest of Merced. When this antenna was constructed in 1965, the signals received at Cressey were transported to Merced, California, by a 44-amplifier coaxial trunk.
The antenna consists of a large reflector constructed of wires stretched on steel supporting structures. In addition, there are several other VHF, UHF, and CARS antennas located at the site.
Here is a photo of the site, contributed by Bryan Wade:
At first glance, we notice several antennas in this photo:
But the VHF receiving antenna we're discussing here isn't immediately evident. Note the ten shorter towers spread across the lower half of the photo:
Note the shape of these towers:
Now imagine a series of steel wires stretched along the parabolic inner surface of these towers:
These wires define a surface in the shape of modified torus . It's the same shape as the surface of a "Simulsat" satellite antenna (or, more precisely, the top half of a Simulsat):
Like the Simulsat reflector, this surface focuses incoming RF signals onto a locus of focal points (the "locus of foci"):
| Sketch: Neal McLain |
The immense size of this reflector provides extremely high gain at frequencies in the VHF band. Receiving antennas placed along of the locus of foci can detect these signals.
This antenna was constructed in 1965 by General Electric Cablevision. It was originally built to receive VHF television signals from two transmitter sites in the San Francisco metro area — Mt. Sutro and Mt. San Bruno — more than 100 miles westnorthwest. The following Google map identifies the locations of these four sites:
View Larger Map
Drag the map east to see Mt. Sutro and Mt. San Bruno.
Frank Baxter was Vice President of Engineering for GE Cablevision for several years. He kindly provided the following description of this antenna:
It is an antenna that is parabolic in the vertical plane and circular in the orthogonal plane. There is a locus of feed positions that exist at one half the distance of the radius of the circle. Using this characteristic permits wide angle scanning by just moving the feed point.
[This] antenna was erected in about 1965 [near] Merced, California, a CATV system owned and operated by General Electric Cablevision until 1986. The screen was about 90 feet high and 360 feet long. The radius of the torus was about 100 feet. The screen was centered on San Francisco and several antennas were placed along the locus of feed positions to cover all the Bay Area signals. The support structure consisted of steel towers with the appropriate curvature and the screen was constructed using horizontal, stretched steel wire. The screen was difficult to see and soon became dubbed 'the bird catcher.' It also had a tendency to 'sing' during high winds.
This antenna was the main source of Bay Area signals for a number of years, and later served as backup to the CARS microwave system that replaced it." 
This reflector was still standing in 1999, although the San Francisco stations were by then being imported into Cressey by a CARS-band microwave network, and the torus reflector served only as a backup. The sole remaining receiving antenna in the locus of foci was oriented toward Mt. San Bruno, site of the KTVU (Fox, Channel 2) and KQED-TV (PBS, Channel 9) transmitters.
Other antennas in the above photo are:
The original design of the torus reflector came from an unknown Canadian firm. According to Frank Baxter, several similar reflectors were built in Canada during the 1960s. But the torus reflector in Cressey, California was the only one extant in 1999.
- The UHF dish antenna on one of the short towers receives a station from Fresno, about 67 miles southeast.
- Two microwave reflectors at the top of the tall tower are part of a two-hop CARS-band network used to import San Francisco stations (received off-the-air at Livermore) into Cressey and Fresno. One reflector is directed toward Livermore (60 miles westnorthwest); it reflects signals arriving from Livermore to a receive antenna on the roof of the equipment building at the base of the tower. The other reflector is directed toward Fresno (67 miles southeast); it reflects signals from a transmit antenna on the roof of the equipment building toward a receiving station in Fresno.
- The satellite antenna near the base of the tower is described by Bryan Wade as "the venerable old 5-meter S-A cassegrain TVRO that I put up about 1975 so folks in Merced could get HBO."
Merced and Cressey are located Merced County, which is in Fresno-Visilia DMA.
Mt. Sutro is located in the City and County of San Francisco. Mt San Bruno is located in San Mateo County. Both counties are located in the San Francisco-Oakland-San Jose DMA.
 This shape does not have a mathematical definition, although it is quite similar to a torus. It differs from a true torus, however, in that the support towers are parabolic in shape, rather than circular. Nevertheless, this surface is often called a torus by antenna engineers.
 Baxter, Frank. E-mail message to Neal McLain, circa 1995.