In a move designed to make it easier for developers to provide cable television service in new homes, Fairfax County has begun encouraging installation of cable TV lines in new subdivisions at the same time other utility lines are installed.

The county's Department of Environmental Management (DEM) has written local developers, engineers and builders advising them to negotiate with Media General Cable of Fairfax Inc. before construction starts rather than "waiting until after the fact," according to William B. Rucker, deputy director of DEM.

However, the county will not require builders to provide easements or even talk to Media General, holder of the franchise to provide cable service to Fairfax. "We are encouraging them," Rucker said.

Fairfax made its recommendation voluntary, Rucker said, out of concern that the county not promote the interests of a private company.

Several Fairfax real estate agents and builders applauded the county's decision. Tony Ahuja, director of technical services for the Northern Virginia Builders Association, said the county's action should mean that homebuilders will be able to offer cable services as an amenity when the time comes to market the house.

"People in Fairfax are so well educated that this will appeal to all age buyers," one real estate agent said. "People who look at schools also will be glad to know that a new home they are considering buying will have cable service immediately available."

"In this market, where there are still many houses for sale and the market is strong competitively, every amenity a seller can offer is a big plus in a new or existing home," said broker William L. (Kip) Laughlin, an officer of the Northern Virginia Board of Realtors and head of Laughlin Realty.

The builders' group was instrumental in bringing county and Media General officials together to help solve what some builders and homeowners describe as a nightmarish problem. Attorney Richard Hausler, of the firm of Hazel, Beckhorn and Hanes, also helped negotiate the agreement.

Media General Inc., owner of several weekly newspapers and two dailies in Richmond, was awarded the contract to provide cable service to Fairfax in September 1982, after heated debate. But homeowners in some neighborhoods have refused to grant rights of way across their land to install cable boxes and lines, preventing the company from providing service to those living beyond the unwilling homeowners' property.

The Virginia Department of Highways and Transportation also has fought installation of cable boxes in many neighborhoods, Ahuja said. "The things look like R2D2 robots from the movie 'Star Wars,' " he said. Safety officials have warned that the boxes could be driving hazards if installed too close to the road. The county's decision to encourage deals in new subdivisions won't solve the existing problems, which must be negotiated on a case-by-case basis.

In exchange for having the right to negotiate with Media General, homebuilders will pre-wire houses for the system, Ahuja said. The first connection will cost the builder $60 and the second connection $40 in the same house, he said.

Fairfax also has developed engineering guidelines that must be met if builders choose to work with Media General to install cable lines at the same time other utilities, such as water and storm systems, are put in place. The new rules apply to detached as well as attached housing.

Rucker said efforts are under way to include the engineering guidelines in the official county Public Facilities Manual, which is considered the bible of building in Fairfax. "It [the manual] translates the legal requirements of subdivision development into engineering language," Rucker explained. For the guidelines to become part of the manual, they must be approved by the Fairfax County Board of Supervisors. Amendments currently are being prepared so the board can vote on the proposals later this fall, Rucker said.

Several real estate agents said they could see the day in the near future when cable television would get stiff competition from so-called "dish" antennas that receive television transmissions via satellite, although the dishes currently available are so large that installation can get area homeowners in trouble with zoning officials unless certain conditions are met.

Ahuja agreed that those systems would become more popular as the size of the dishes decreases. But for now, Fairfax County is trying to ease the way for new home buyers to have cable service as soon as possible with minimal problems.