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New FI940 FM Tee Combiner Now Complete!

An FM channel combiner constructed from two (2) four-section FM reflective bandpass filters will add two new frequencies to an existing three (3) constant impedance FM combiner system. The FI940 is a compact, folded design four-section FM bandpass filter with integrated non-adjacent coupling. This allows two FM channels as closely spaced as 0.8 MHz to be combined with group delay variation that meets the requirements for hybrid analog and HD digital operation. Some manufacturers use five-section filters for these applications, which increases group delay variation to values greater than the 600 nanoseconds maximum recommended.

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New Tower Project for Hall Communications CAT Country 98.1 (WCTK) and WNBH (AM), New Bedford. Massachusetts

The Massachusetts Clean Energy Technology Center (MassCEC) approached Hall Communications about relocating the WNBH 1340 580-foot guyed AM tower that was also home to the FM antenna used by their WCTK FM 98.1. This project, of significant importance, would allow the Port of New Bedford to expand the harbor facility to support the offshore wind power project planned off Cape Cod, a testament to the crucial role of Hall Communications in this initiative.

The FM would be relocated to a new self-supporting 600-foot tower located on one corner of the harbor facility, while the AM tower would be relocated to a new site 2.5 miles northwest of the current location. Hall Communications has a long relationship with ERI as a hardware and services supplier. After receiving the initial designs for the new towers, antennas, and their installation, MassCEC awarded ERI the first of a series of contracts to provide the new towers and destack the old 580-foot guyed tower when the new transmission facilities were completed.

The new WCTK self-supporting tower is constructed of galvanized solid steel members and has a 50-foot face at the tower base, and the soil conditions required that the tower foundations be drilled shafts. ERI subcontracted the tower installation to Tower King II of Cedar Hill, Texas. The ERI self-supporting tower has many useful standard features,  including step bolts with tie-off attachments on all three tower legs to make access to the whole structure easier. These climbing devices transition to integrated climbing rungs on one face of the structure when it narrows to 48 inches.

At the top of the tower is a 36-inch face ERI LAMBDA® Frequency Optimized FM Mounting System. The 60-foot LAMBDA® Mounting Sections support the WCTK SHPX-8AC-HW Main FM antenna. The antenna underwent testing on the ERI Far Field Test Range to select the optimum mounting configuration for the array on the new tower. The range testing is done on the actual LAMBDA tower sections that will support the new array on FM antenna systems that include new LAMBDA mounting sections. In addition to the new main FM antenna, the system supplied by ERI included an ERI SHPX-6AC-HW auxiliary FM antenna mounted on an ERI-supplied standoff mounting pole. on the tapered section of the tower 400 feet above ground.

In addition to the new tower and FM antennas, ERI supplied a 788 All Pass™ High Power HD Radio FM Analog/IBOC Diplexer to combine separate analog and HD digital FM transmitters. As a Class B facility, with the halfwave spaced main FM antenna the analog TPO required is 24 kW, which made the selection of separate analog and HD FM transmitters a more attractive option than a low-level combined FM transmitter given the low insertion losses of the All Pass™ Diplexer.

The new WNBH 1340 AM tower is a 196-foot guyed tower that supports a three-wire Folded Unipole antenna supplied by Kintronic Labs. The AM tower installation was also subcontracted to Tower King II. After the AM tower installation was completed and both WCTK and WNBH had fully relocated their transmission facilities to the new tower sites, Tower King destacked the old 580-foot guyed tower so the Port of New Bedford could begin the construction of their expanded facilities, which building constructing the offshore wind power facility that will provide clean electric power to Southeastern Massachusetts.

Links to Other Sites

600-foot Tower Construction for WCTK CAT Country 98.1 YouTube WCTK Tower Construction
Photos of the new WBNH 1340 AM tower NECRAT WNBH AM1340
Photos of the new WCTK FM tower and the previously active WCTK/WBNH guyed tower NECRAT WCTK
All photos are provided courtesy of Mike Fitzpatrick. Many more can be found at NECRAT.US

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A Few FM Antennas on Mount Wilson

IHeartMedia’s ERI 6-Bay LYNX Dual Input FM antenna, which is the top-mounted antenna on the left, combines separate FM analog and HD digital transmitters. At the time it was installed, this was the lowest-loss method for broadcasting hybrid HD Radio signals. The antenna on the right is sister station KOST’s ERI MPX-4E FM antenna. KLLI’s directional 1182-2CP-DA FM antenna is owned by Meruelo Group. Photo courtesy of Doc Searls, see more here.

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A New Three-Bay ERI LPX Series FM Antenna in Final Tuning and Test

A new three-bay LPX Series ROTOTILLER® FM Antenna has been tuned and is now under a pressure test to confirm the assembly does not leak air. After the test, the antenna will be painted and packed for shipment to the customer. The LPX-3E end-fed array is rated to handle up to 9 kW, and it is available with radomes or electrical deicers for installations in harsh Winter climates.