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Christmas Lights Cheer an AM Transmitter Room

Tim Wright sent us this photo from his shop at WLS

The transmitter room of WLS(AM) radio station in Chicabo with a Christmas tree in front of the Nautel transmitterLooks like the transmitter room of WLS(AM) is in the Christmas spirit.

Cumulus Chicago Senior Engineer Tim Wright put up the tree and lights. The site in Tinley Park, Ill., serves as his “office” and doubles as a workshop for the Cumulus Repair Depot.

“The building was built in 1938 to house the RCA 50D transmitter on 870 kHz, before the big move in 1941 to 890,” Tim tells us.

“The site was shared with WENR(AM) on a timeshare basis until WLS bought out the WENR license. It replaced a joint site in Downers Grove, Ill., that was built by WENR, and running 50 kW with an RCA R.T.150-B-1, Serial Number 30405.

“WLS was previously located at a site in Crete, Ill., running 5 kW using a Western Electric Type 104-A-V.T. telephone transmitter, according to the FCC license paperwork from the time. The 50D stayed in service until 1959, when it was replaced with a GE 50 kW transmitter, and that in turn was replaced with a pair of Harris MW-50s in 1977. One MW-50 was replaced with a Continental 317-C3 in 1989, and the other by a Harris DX-50 in 1997.”

The Continental 317-C3 was replaced with this Nautel NX-50 in 2021.

[Related: “The WLS Tower: Radio History in the Moonlight”]

Tim adds that at left we can see a “heads up” display using Node-Red to ingest data from SNMP, HTML Parsing and Telnet for storage in an influxDb and display on a Grafana interface. The top display is a static image, the middle one is satellite receiver status for the XDS and Wegener units here and at the studio, and the bottom monitors the transmitter facility.

“Don’t worry, the two areas that say OFF AIR are for the DX-50 backup, which is offline,” he wrote in an email.

“We run WLS in MDCL for power savings, so most of the time the carrier shows 25 kW or thereabouts. The two Honeywell fire system strobes are used for silence detect alarm (Flash only, Amber) and carrier alarm (Flash and audible alarm, clear).”

Tim adds that blue LEDs are used in the Burk interface units. “I am red/blue colorblind, and I could not see the red/green status, so I changed the LEDs. I also changed out all the red/green LEDs in the DX-50 colorstat panel to red/blue.”

Send us your own photo that captures your experiences of life as a radio engineer. Email [email protected].

[Related: “Sunset Photo Captures the Beauty of Mount Wilson in Snow”]

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