KFIO - Sherwood and Ziegler Buildings

Used Two Transmitter Plants

From 1934 to 1952, KFIO used the rooftop of the Sherwood Building, 510 West Riverside Avenue, to mount the antenna system. At the same time, the station used the Fidelity-Ziegler Building, 526 West Riverside Avenue, to house the transmitter as well as its studios and offices. The Fidelity-Ziegler Building was razed in 1952. KFIO, at this site, had two transmitter plants. The original one was a 100-watt composite broadcasting transmitter and an inverted "L" antenna and was used from 1935 to 1941. The second one featured a 250-watt transmitter and a self-supporting antenna and was used from 1941 to 1952. The descriptions of both transmitter plants are below.

First Transmitter Plant - 1935-1941

KFIO's first transmitter plant at the Sherwood Building was licensed for use from 7 May 1935 to 25 March 1941. This transmitter was rebuilt in 1934 and was used a short time at the Pedicord Building before being installed in the Sherwood Building. The license records describe it as a composite broadcasting transmitter with direct crystal control and rated the carrier output power at 100 watts. The antenna was an "L" type that was supported by two towers on the rooftop of the Sherwood Building. The towers were said to be 178-feet above the ground level, and the height of the towers above the rooftop was about 80 feet. The horizontal length of the antenna was 185 feet and the vertical lead-in was 80 feet. The ground system was described as 5,000 feet of ground shield copper clad cable. There are no known pictures or drawings of this set up.

Second Transmitter Plant - 1941-1952

KFIO's second transmitter plant at the Sherwood Building was licensed for use from 26 March 1941 to early 1952. The author was able to locate one photograph of this tower in the National Archives. You can see a thumbnail of this photograph to the left. Click on it for a larger image.

The transmitter was an RCA type 250-K with direct crystal control and high level modulation. The antenna was a 150 foot tall series-fed tower and topped out at 248 feet above the street level. The ground system consisted of 165 radials about the tower. The center was grounded to a copper pipe and to a sprinkler system. The ground radials were attached to nearby buildings, including twenty wires which crossed Riverside Avenue. For details of the proposed ground system see the diagrams below.

Tower Razed in February 1952

The dismantling of the Sherwood Building tower began in late February 1952 after a new tower was built on the Realty Building earlier in the month. The move from the Sherwood Building happened because the Fidelity-Ziegler Building, the building next to the Sherwood, was being razed. The Fidelity-Ziegler Building had held the station's studios and business offices. Louis Wasmer, the station owner at the time, noted that the new building taking the place of the Fidelity-Ziegler Building would be higher and block signals from the Sherwood Building tower. Thus the move to the Realty Building was needed. (For information about the tower on top of the Realty Building see here.)

Written by Bill Harms - updated 30 September 2008


The Sherwood Building

Photos courtesy of www.preservationdirectory.com

The First Transmitter Plant

Schematic of the transmitter first used at this site.

(From the National Archives)

The Second Transmitter Plant

Sketch drawing of the ground radial sytem. (From the National Archives)

Details of the ground system showing heights of the buildings and tower location. Notice the location of the Ziegler Building to the left of the Sherwood Building. (From the National Archives)


  1. KFIO Radio Broadcast Construction Permit. Federal Communication Commission. Washington, DC.
  2. KFIO Radio Station Licenses. Federal Communications Commission. Washington, DC.
  3. "Neck Craners Eye Tower Dismantling." Spokane Chronicle. Spokane, Washington. 27 February 1952. Page 3.
  4. "Smith Sells KFIO to Louis Wasmer." Spokane Chronicle. Spokane, Washington. 24 January 1950.