I don't believe there was a Mk.28 radar - from all my research, the Mk.33 director normally did not mount a radar until mid-war, when they were fitted with Mk.4 radars. . .
Mark 28 radar was mounted on Mk.33 directors
some reference also see pic
where the circled dish on the Mk.33 director is the mk.28 radar
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Thank you Kim for the crest
"Never fear to try on something new. Remember that the Titanic was built by professionals, and the Ark by an amateur"