Radio OfficersMaritime law stipulated that ships should have at least one fully qualified Radio Officer, who were either employed direct by shipping companies or worked for one of the Marine Radio Companies.
The Maritime Radio Museum website has an interesting article on Radio Operators that may be of interest to you.
“The Radio Operators on QE2 were all employed by a Cunard subsidiary,
Radio and Electronic Services, based in the Cunard Building in Liverpool. This company prided itself on being much more technically orientated and other shipping lines who generally employed Radio Operators and when things went wrong a local agency came on board to fix things. “
Willum
Image above: Don Butterworth, Chief Radio Officer, who joined Radio and Electronic Services in 1939, was the longest serving Radio Officer in the group. He had war service during WW2 and had survived onboard torpedoed ships. Don had supervised the installation of the radio equipment during the building of QE2 at John Brown's shipyard in Clydebank.
Radio Officer staffing compliment:When the Radio Room was being planned in the 1960's it was envisaged that there would be nine Radio Officers onboard at any one time.
However, when the ship went into service, the reality was six Radio Officers:
Chief Radio Officer
Five Radio Officers (1st, 2nd, 3rd, 4th 5th Radio Officers)
The 3rd, 4th and 5th Radio Officer worked shifts similar to Navigation Staff of 4 hours on and 8 hours off
The Chief Radio Officer and 1st Officer filled in as additional staff as and when required. Roger Latham also remembers that two typist assisted during the Maiden Voyages to operate the teleprinters. (see Roger Latham’s article)

Photo: Willum seated, (Actually receiving a telegram from Buck House at that very moment) Standing L-R Brian Martin, Ian Hamilton, Allan Holmes and Peter Hughes.
After the re-engining of QE2 in 1987 advancements in Radio Communication resulted in the number of Radio Officer being reduced to three Officer, plus there were two assistants handling the telephone calls (source: QE2 Cunard's Flagship page 85).