Robertshaw Controls Co. of Richmond reported yesterday that profits rose last year to $10.2 million ($2.61 a share) compared with earnings of $8.6 million ($2.20) the previous year, which was after a one-time charge of $2.6 million (66 cents). Sales rose to $349 million from $327 million.

The manufacturer of heating controls and timing devices said fourth-quarter profits were a record $4.1 million ($1.11) compared with $3.2 million (82 cents) as sales increased to $92 million from $87 million.

President Ralph Thomas said the forth-quarter gains reflected strong temperature-control and export sales as well as continued international expanison. He said that while Robershaw expects 1981 to be better than last year, the first quarter is not expected to be strong.

Media General, a Richmond communications company that owns newsprint mills, broadcast stations and that city's daily newspapers, reported record sales and profits for 1980. Earnings rose 11 percent to $28.3 million ($3.91 a share) compared with $25.4 million ($3.42) the previous year as sales increased 18 percent to $332 million.

In the latest quarter, earnings were $7.5 million ($1.03) on sales of $87 million compared with earnings of $7.47 million ($1.01) and sales of $78 million a year earlier. Pretax profits were up in all three divisions, although newspaper division profit gains were the smallest.

Radiation Systems Inc. of McLean said profits rose in the six months ended Dec. 31 to $379,000 (48 cents a share) from $329,000 (41 cents) as sales jumped to $4.2 million from $2.6 million.

President Richard Thomas attributed the gains mainly to higher sales of commercial satellite large antenna products.

First American Bank N.A., the D.C.-based flagship for the Financial General Bankshares Inc. holding company, said fouth-quarter operating profits rose to $1.7 million (75 cents a share) from $1.4 million (62 cents).

For a full year, operating earnings were $6.38 million ($2.80) from $6.05 million ($2.66).

Fredrick County National Bank reported 1980 earnings of $492,879 ($4.07 a share) compared with $445,213 ($3.78). Assets rose 18 percent to $54.5 million.

General Kinetics Inc. a Rockville magnetic tape technology firm, reported earnings of $37,330 (5 cents a share) in the six months ended Nov. 30 compared with a year-earlier loss of $11,446 as sales rose to $1.79 milion from $1.19 million.