|Branding||CHOK 103.9 FM & 1070 AM|
|Slogan||News, Sports, Information|
|Frequency||1070 kHz (AM)|
|Repeater(s)||103.9 MHz (FM)|
|First air date||July 26, 1946|
|Power||10 kW (AM)|
|ERP||200 watts (FM)|
|HAAT||59 m (FM)|
|Sister stations||CHKS-FM, CFGX-FM|
CHOK is a Canadian radio station, licensed to Sarnia, Ontario at 1070 kHz and owned by Blackburn Radio. The station broadcasts a gold-based adult contemporary music format with local news, talk and sports. CHOK also has an FM translator, CHOK-1, broadcasting at 103.9 MHz.
The station was launched on July 26, 1946 by Sarnia Broadcasting. In 1947, Sarnia Broadcasting Co. was granted a licence to operate an FM station at 97.5 MHz (as CHOK-FM), which left the air in sometime in between 1948-1953 after being damaged from the Sarnia tornado. That station was never rebuilt. It was acquired by IWC Communications, a corporate precursor of Standard Broadcasting, in 1970, and went through a variety of sales to local owners until being acquired by its current owner, Blackburn Radio, in 1998. Blackburn also owns both of the city's other commercial radio stations, CFGX-FM and CHKS-FM.
In April 2007, CHOK AM applied to add an FM transmitter (CHOK-1-FM) at Sarnia to broadcast at 103.3 MHz and simulcast the programing of CHOK 1070 AM, due to AM reception problems from metal and steel associated with the operations from petrochemical plants. Another company, Points Eagle Radio, had applied at the same time to use the 103.3 MHz frequency to broadcast Aboriginal programing. Points Eagle Radio was given approval by the CRTC to use the 103.3 FM frequency on August 7, 2007.
On July 20, 2007 CHOK was given approval in part to broadcast at 100.9 MHz. On October 10, 2007 Blackburn Radio applied to use the frequency 103.9 MHz instead. On January 18, 2008 CHOK was given approval to use the 103.9 frequency with 200 watts power. 
CHOK began testing of its 103.9 FM transmitter atop the Kenwick Building in downtown Sarnia, on June 18, 2008. On the morning of July 23, 2008, CHOK signed on as Country 103.9 FM and will continue to simulcast its signal on 1070 AM.
The station also has a low-power license-exempt repeater on 101.5 FM at the Sarnia Sports and Entertainment Centre. The 101.5 FM frequency is reserved for use by the CBC, should they choose to broadcast on that frequency in the future.
On May 21, 2013, CHOK dropped its country format and changed its music to a gold-based adult contemporary music, with some country and classic hits mixed in. The service elements of the previous format remain in place, with hourly news reports and local talk programs. The music leans older and softer than the hot mainstream AC format of sister station CFGX-FM. Toronto Blue Jays games, which had been off the air since 2006, returned to the station, as did the Sarnia Sting.
The format change came as WHLS in Port Huron updated its format from oldies to a classic hits mix. WHLS would later flip to alternative rock in 2015 as Rock 105.5, leaving CHOK the only remaining station in the market that still plays pre-1980s hits as WGRT, WBTI and sister CFGX-FM have more modern AC formats.
- CHOK history - Canadian Communications Foundation
- Query the REC's Canadian station database for CHOK