This RF system includes two (2) 6-section UHF band pass filters and will be part of a two-cabinet UHF television transmitter that will operate with a transmitter power output (TPO) of 30 kW. The two individual power amplifier cabinets will operate at 15 kW each and each have their own 6-pole band pass filter at the filter outputs a 6-inch 3 dB y-brid will combine their output to achieve the 30 kW total power required to achieve the station’s authorized effective radiated power (ERP).
The ALP Series, with a medium cardioid azimuth pattern, UHF television antenna is almost finished packing and will be leaving to begin service as an auxiliary antenna for a Full Service TV station. This is a low power model which is rated to handle up to 5 kW average power. The medium power version handles up to 10 kW.
The new ERI tower for Block Communications is nearing completion. ERI has manufactured and has almost completed the installation of the new 945-foot tower for WDRB and WBKI serving Louisville, from Floyds Knobs, Indiana. The structure will have an overall height of 1,000-feet when the two top mounted, elliptically polarized, UHF television antennas are installed. The tower is topped with a T-Bar which supports the two antennas with centers of radiation at the same height above ground level and with a separation of 30-feet between them, to minimize distortion of each antennas’ horizontal plane pattern. In addition to the two top mounted main antennas the tower also supports an auxiliary antenna for each station which are side mounted between 775 and 890 feet above ground level.
ERI maintains an inventory of emergency stand television antennas to be used during new antenna installations and to get stations back on-the-air in emergency situations. The antenna pictured is a broadband UHF panel antenna that has 7.5 kW average power handling capability and includes a mounting with integrated leg mount brackets. This UHF television antenna is horizontally polarized and can be used on any RF channel for 14 to 51 (470 to 698 MHz).
This is a four (4) station constant impedance FM combiner system for four Full Service FM stations. The operating frequencies of the FM stations in the combiner system and collocated with the Master FM Antenna these four station will use are all closely spaced channels so the band pass filters in the system are all four-pole and include optional non-adjacent coupling loops to provide additional suppression at the band edges of each filter bank while reducing group delay variation.
This ERI Model MPX-8C Medium Power ROTOTILLER® FM Antenna is tuned and painted and heading for packing. This FM antenna is bound for Fairbanks, Alaska, to be used by KUAC-FM, the University of Alaska-Fairbank’s NPR member FM station. The antenna will be installed on Ester Dome near North Pole, Alaska.
This is one element of a new 1193-6CP-DA directional FM panel antenna which includes eighteen 1190 FM panel elements configured as three curtains of six layers (bays) each. The system has completed pattern development and range testing at ERI test range. The next step is to fully assemble and tune the array and then it will be packed and shipped to site.
KQED(FM)’s Chief Engineer, Larry Wood, authored for Radio Magazine an excellent chronicle of their four-year project to upgrade their transmission plant, which included relocating their transmitter room to a larger space and upgrading the new facility with a new Nautel NV80, combined NV40 FM transmitter. ERI provided a Model CY301-0FM FM Switchless Combiner to Nautel to combine the two NV40 cabinets and provide switching to allow either cabinet to be put on-air. In addition, ERI supplied a custom coaxial patch panel and switching system that provides additional transmitter switching redundancy and 1329Line aluminum outer conductor rigid line for the interior RF plumbing. ERI also designed and manufactured both the Main and Auxiliary KQED(FM) ROTOTILLER® FM antennas.
WEHT NEWS25, ABC’s affiliate serving Evansville Indiana, has completed the construction of its post transition digital television transmission facilities. The construction of WEHT’s final digital transmission system was complicated by its change from its assigned out-of-core pre-transition, RF Channel 59 to RF Channel 7. Until the June 12, 2009, digital transition deadline, Channel 7 was occupied by the FOX affiliate, WTVW’s, NTSC analog signal.
Electronics Research, Inc. provided the new main and auxiliary digital television antennas for WEHT, as well as structural engineering services, tower reinforcement materials, and installation services. The WEHT tower was originally constructed in 1966 and is co-located with WEHT’s studio facilities in Henderson Kentucky. The new antenna required for WEHT’s post transition digital operations on a VHF RF channel was larger and heavier than the channel 25 analog antenna and thus required a complete tower inspection, including ultrasonic inspection of the guy wire anchors, and a tower reinforcement design to support the new digital antennas and handle the erection stresses associated with their installation.
The reinforcement design brought the tower structure into compliance with the ANSI/TIA-222 standard and required the replacement of three (3) guy levels with stronger bridge strand wire. In addition to the new guy wires the reinforcement project also included the fabrication and installation of split pipe reinforcements on most of the tower legs and upgrading the tower cross bracing. The final portion of the makeover was the replacement of the top 30-foot section of the tower with a brand new tower section that included a mounting flange for the new ERI TRASAR television antenna.
The new top mounted antenna is an ERI model ATW9V3-CTO-7 TRASAR, circularly polarized, coaxial slotted array antenna. The antenna was designed and fabricated at ERI’s manufacturing facility in Chandler, Indiana, approximately 20 miles from WEHT’s studio and tower complex. In addition to the top mounted main antenna, ERI supplied and installed a side mounted standby antenna which was used to maintain over the air broadcasts immediately following the June 12 transition date while the tower reinforcement project was underway.
WEHT was Evansville’s first television station, signing on in 1953, on Channel 50. Gilmore Broadcasting acquired the station in 1964 and moved it to Channel 25. WEHT has been Evansville’s ABC affiliate since 1995. Shortly after initiating its post transition digital transmissions WEHT activated a second digital channel as an affiliate of the Retro Television Network, branded as RTV 25 on digital channel 25.2. In addition, to RTV’s network programming WEHT also produces a 9:00 PM edition of its local news program, NEWS25.
Located in downtown Minneapolis the communication towers on top of the IDS Center, 910-feet (277-meters), are the highest point in the State of Minnesota. ERI provided a 12-Bay AXIOM Master FM Antenna which serves as a combiner auxiliary FM antenna system for a number of major FM radio stations who formerly broadcast from this as their main transmitter site. They now use the IDS as a backup in case their primary location in Shoreview, Minnesota were to fail or when shut down for maintenance. The AXIOM Master FM Antenna is a broadband side mounted antenna that can be configured to handle a combined power levels up to 240 kilowatts. The communication spires on top of the building tower to 910 feet (277.3 m), making them the highest point in Minneapolis. The top of the IDS is also used for microwave transmission and reception by WCCO-TV, KSTP-TV, KMSP-TV, and KARE news trucks, in order to relay video to their stations.