In Old Town Alexandria, where every sign and storefront must blend with the antique structures of the onetime Colonial seaport, a businessman is planning to paint his rooftop satellite dish the color of bricks.

"We're trying to be as discreet as possible," said Jim Reedy of the Private Satellite Network in New York, which plans to install the dish atop the six-story George Mason Building so that a broker's Alexandria office can receive transmissions from its corporate headquarters. Discretion in this case means painting the dish the rust color of some Old Town buildings.

In a city that revels in its history and likes to refer to itself as the home town of George Washington and Robert E. Lee, the matter of satellite antennas has aroused considerable interest since the satellite network firm and an audio supply store asked last fall for permission to erect antenna dishes.

The city's Board of Architectural Review last week gave Reedy permission to install the dish on the building at Prince and South Washington streets for a trial period.

Before last night's City Council meeting, council member Patricia Ticer, a Democrat who represents Old Town, said that dishes are "very, very ugly and inappropriate for an historic district" and that she is shocked they are being allowed even on a temporary basis.

The council went ahead to direct the city Planning Commission to study the question of whether special use permits should be required to place the antennas.

Some citizen groups are poised to do battle over the issue. "Pretty soon, the ambiance that's so attractive about the historic district is going to be lost forever," declared Oscar Fitzgerald, chairman of the Historic Resources Commission, which opposes the dishes along with the Old Town Civic Association.