The Model 425 FM Isolation Transformer is finished with tuning and test, and it’s way to shipping. This type of transformer allows the transmission line feeding an FM antenna to pass the transmitter power across the base insulator of a series fed AM tower. The Model 425 is rated to handle up to 25 kW of FM power and up to 40 kV Peak AM Voltage while adding very little additional AM Shunt Capacitance.
The radomed elements are part of a new 12-bay SHPX Series diplexed FM antenna built for an FM station in northern Iowa. The interbay lines in their crates, and now the last of the elements are staged for packing.
The two towers pictured are 328-foot self-supporting towers owned by American Tower on West Tiger Mountain east of Seattle, Washington. The towers were manufactured and erected by ERI in 1999. The tower on the left includes a T-Bar that supports two UHF television antennas. The tower on the right now supports a new ERI LAMBDA® Optimized FM Mounting System that is 135-feet tall. The FM antenna is a 16-Bay AXIOM® Master FM Antenna that is fed by two 6-1/8-inch, 50-ohm, rigid transmission lines. The antenna is the primary FM antenna for six Seattle FM stations.
These two ERI FM antennas serve different FM stations in Milwaukee. The upper antenna is WXSS’s ERI Model SHP-4AE-HW ROTOTILLER®, which is a 4-bay, half wavelength spaced array mounted at 899-feet above ground level. The antenna below it is an ERI LYNX™ 4-bay Model DI-4A dual input FM antenna at 863-feet above ground level which is WKLH’s main antenna. The LYNX antenna has separate analog and digital HD Radio™ inputs and the antenna combines the separate FM analog and HD signals to provide a hybrid FM signal. The antennas are located on the WVTV-TV/Milwaukee PBS tower located in Milwaukee’s Estabrook Park neighborhood.
This is an 8-Bay AXIOM® Master FM Antenna just completing final test and almost ready to be taken down, get painted and packed for shipment. The system supplied by ERI also includes a three station FM channel combiner.
This 1,000-foot tower support WLDR-FM’s ERI Model SHPX-8BCSP/LP-6C-SP Shared Aperture FM antenna. The antenna is an interleaved array made up of a high power 8-bay SHPX Series ROTOTILLER® for the analog FM signal and a low power Model LPX-7C ROTOTILLER® for the digital HD Radio™ signal. To provide additional isolation the antennas are cross polarized, the analog signal has right hand circular polarization and the digital is left hand circularly polarized. Photo courtesy of Doc Searls and can be found at flickr.
The tower pictured is a 996-foot guyed tower that supports WTCM-FM’s main antenna which is an ERI manufactured G5CPS-10AC, which is a private labelled FM antennas built for Continental Electronics. If you look carefully you can see WTCM-FM’s auxiliary antenna which is an ERI Model 300-3AE vertically polarized FM antenna at 615-feet above ground level. Photo courtesy of Doc Searls and can be found here: flickr.
This is an auxiliary AXIOM® Master FM Antenna for KBIG/104.3 (21kw), KIIS/102.7 (4kw), KOST/103.5 (10kw) and KRRL/92.3 (19kw). The antenna is a true broadband master FM antenna, this model is an 8-bay version. The array has half wave bay-to-bay spacing and has a unique feed system that is broadband over 18 MHz of the FM band. Photo courtesy of Doc Searls and can be found at flickr
This is a top mounted, elliptically polarized, UHF TRASAR® television antenna in the process of having final test data taken. All ERI top mounted television antennas are provided with dedicated climbing facilities that do not penetrate the radome. This prevents potential contamination or moisture intrusion into the antenna radome which can cause corrosion, impact electrical performance and shorten the antenna’s useful life. This also provides climbers superior access to the beacon and improves safety.
This item is an ERI Model 788A-SP High-Efficiency FM Analog/HD Digital Diplexer. ERI’s innovative All Pass™ design allows stations to operate hybrid digital with HD Radio™ power levels up to -10dBc. The All Pass Diplexer maintains high efficiency while incurring a much smaller penalty to performance than other methods currently available. The analog insertion is less than 0.35 dB, and the digital HD Radio signal loss is less than 1.4 dB with digital group delay variation less than 600 nsec and is fully compliant with the HD Radio™ FM Transmission System Specifications. The 788 is an ideal choice for FM stations that have very high FM transmitter power output requirements due to long transmission line runs and also have the desire to operate at elevated HD power levels.