Penril Corp. of Rockville reported record earnings of $477,000 (36 cents a share) for the quarter ended Jan. 31, up from $416,000 (32 cents) in the same period a year ago.

The gains during the period, the second quarter of Penril's fiscal year, boosted first-half earnings to $878,000 (66 cents) from $652,000 (50 cents) the previous year.

The Rockville electronics manufacturer said first half revenues were 62 percent ahead of the prior year -- $16 million versus $9.8 million -- and second quarter revenues increased 3 percent to $8.6 million from $6.5 million.

Penril's directors raised the company's semiannual dividend to 7-1/2 cents a share [WORDS ILLEGIBLE] year from 13-1/4 cents paid last year.

Penril, whose shares are traded on the American Stock Exchange, makes data communication gear, electronic test and measurement instruments, power conversion equipment and loudspeakers.

Systematics General Corp. of Falls Church reported preliminary results that show the company will post a $346,000 loss for 1979, down from a $189,000 profit the year before.

The loss, the company said, was due to Systematics' decision to cancel a contract with the U.S. Army. The cancellation required the company to set up a $340,000 reserve for its possible loss on the contract.

Systematics reported revenues for the six months of $7.8 million, up from $4.5 million in the same period a year ago.

American Health Services of Washington reported its pre-tax operating income fell last year to $1.78 million from $2.68 million but its net increased because of a $3.5 million gain from the sale of real estate.

American Health, which runs four psychiatric hospitals and a nursing home, reported net earnings of $3.19 million ($3.73 a share) compared with $1.28 million ($1.50) a year earlier.