President Reagan's State of the Union Address last January almost didn't make it out of the White House. With Washington blanketed by one of its worst blizzards in years, many of the microwave systems and satellite earth stations that usually carry the broadcast signals of the major television networks and news services out of city were snowed under.

But the broadcast facilities at Washington International Teleport were working and, for three crazy days, the Northern Virginia telecommunications firm handled the transmission requests of dozens of broadcasters and worked overtime to keep official Washington on the air.

"The president was addressing the nation. The Democrats were broadcasting their response. The Iran-contra story was just breaking," recalled WIT President Bruce Kirschenbaum. "It was an incredibly busy time."

WIT has been acting as the Washington area's largest broadcasting intermediary for the last five years. From an eight-acre site just inside the Beltway in Springfield, the privately held firm, which expects revenue of $10 million this year, ferries the video signals of 25 customers, including Cable News Network, the U.S. Chamber of Commerce, the BBC and C-Span, in addition to the emergency requests of others.

WIT sends the signals out of Washington by microwave relay and then by satellite link to television stations around the country and the world.

Now the company is offering a new range of services to expand its role still further. To keep up with the current boom in Washington broadcast coverage, it has invested $1.6 million in two new international earth stations and has entered into an unusual arrangement -- known as Capital Coverage -- with C&P Telephone to provide on-site video link-ups for broadcasters at the State Department, the White House, the Capitol and other news spots around the city.

"What they're doing is making it possible for medium to small people in the broadcast business to get the same types of news access that right now only the largest players can afford," said Bob Ellis, president of Aries Group, a telecommunications consulting firm in Washington.

At present, the major networks broadcast live from such places as the White House by hooking up their own cameras to special video cables that run back to their broadcast headquarters. Smaller broadcasters, who can't afford to lay their own transmission cables, either don't do such broadcasts or rent satellite uplink trucks -- the so-called TV stations on wheels -- that allow them to beam video signals directly from the news site to a broadcast satellite.

But trucks are expensive, costing as much as $1,400 for an afternoon. With its new Capital Coverage, WIT is offering smaller broadcasters the opportunity to share the use of video cables owned by the telephone company.

C&P already has or is building switchable fiber optic cables linking most major news sites in the city with its main switching center. WIT is leasing those lines from C&P and selling time on the cable to various broadcasters. WIT then beams the signal by microwave relay from C&P's downtown headquarters to its own satellite transmission facilities in Springfield.

"It's a really good deal," said Al Levin, who admits that his own business -- Video Transmission Systems, which provides satellite trucks and other video uplink services for foreign broadcasters -- may be affected by WIT's Capital Coverage. "It's just a better blend of technology. You can't fight it."

At the other end, WIT is offering for the first time direct access for its broadcasting clients to Intelsat satellites that serve the Atlantic region. With the aid of two new broadcast dishes, which rise four and six stories off the ground respectively, the company will be able to broadcast directly via satellite to Latin America and most of Europe and Africa.

Previously, WIT had to send the transmissions of its international clients on a "double hop" to an earth station in Maine before they could be beamed overseas. The new dishes will allow WIT to reduce its international rates by 30 percent.

"For $550 an hour, we'll take a video feed directly from the north lawn of the White House to a satellite serving half the world," Kirschenbaum said.

WIT's new services are targeted for a Washington news market that has grown dramatically. In the early 1970s, before the widespread use of video, events at the White House and Capitol Hill were covered by camera crews from the three major networks, and few others. Today, between 100 to 150 journalists, about half of whom represent the broadcast media, attend White House briefings.

"To be credible in local broadcast markets around the country, it's not enough anymore to read copy off the AP news wire," said Ellis, explaining the explosive growth in broadcast media coverage of Washington. "Expectations are higher. Smaller broadcasters have to compete with the big guys."

There are at least a half-dozen small broadcast services in Washington filling the growing demand for specialized and unedited transmission of national political events.

Foreign media coverage of Washington is increasing as well. A year and a half ago, for example, ITN, Britain's second-largest television network, broadcast from Washington an average of 15 minutes a day. This summer, that rose as high as 1 1/2 hours.

The deregulation of American telecommunications that began three years ago with the breakup of AT&T has fueled that boom by making broadcast services much more affordable and flexible. WIT, for example, will control the Capital Coverage system by means of a direct computer link with C&P switching facilities in downtown Washington, marking one of the first times a telephone company in the United States has given a customer access to on-the-premises equipment.

"We need to offer our customers an alternative to traditional telephone service," a C&P official said, explaining the leasing and switching arrangements with WIT. "As new advances in telecommunications technology drive access fees up and competition increases, we have to find new ways to offer our customers sound alternatives."

At the same time, WIT is offering its clients direct access to international satellites because of a 1984 FCC ruling that broke up the domestic international earth station monopoly enjoyed by the American telecommunications consortium, Comsat.

Another local company, Overseas Telecommunications Inc. of Alexandria, has built an international satellite transmission facility similar to WIT's. OTI is privately held, with annual revenue in the $7 million range. Its uplink service became operational late last month.

Both firms also are using their satellite transmission facilities in the burgeoning field of corporate voice and data communications. WIT has even signed up with the EMCO Group of Gaithersburg to offer a satellite video-identification system for use by police around the world.

The system involves electronically recording a video "mug shot" onto a laser disc and transmitting it internationally through WIT's earth station and satellite uplink facilities.

The technology will enable law enforcement groups to conduct teleconferences to and from headquarters and field offices, and permit witnesses to give live video depositions to investigators from remote locations.

"Historically, these kinds of markets were open only to telecommunications giants like AT&T or ITT," said Andy Lipman, a partner with Pepper, Hamilton, and Scheetz, a telecommunications law firm in Washington.

"What's happened is that niche markets in international communications have been opened up for entrepreneurial-size companies. Before, companies like WIT wouldn't even show up on the radar screen.