Alexandria's two-way radio network, used by city agencies ranging from the Public Safety Department to the dog catcher, has too few channels for too many users, city officials say.

In addition, police, fire and public works offices cannot communicate with each other because of three incompatible systems.

The situation has prompted city officials to look for an integrated radio system to be ready for use by the time the new Public Safety headquarters on Eisenhower Avenue opens in 1987.

"We couldn't talk between any one of those three departments, come hell or high water," said Charles Kenyon, transportation chief for the city's Transportation and Environmental Services Department.

The public works system has 132 radio units, from 11 different departments, that can transmit over only two channels.

During snow emergencies, all public works radio users shift to the second channel except snow plow operators and DASH buses, but even two users on one channel becomes a problem as they compete for the airwaves.

Dave Van Fossen, general manager of the Alexandria Transit Co., recalled that once last winter it took 10 minutes to relay news of a bus accident because of other users on the radio.

"Our most acute problem is in inclement weather -- snow and ice. Buses get delayed or in trouble with bad roads," Van Fossen said. "If somebody 'keys over' [tries to call simultaneously with another microphone], they'll have to start the transmission over."

The fact that radio users cannot be monitored with the present system has lead to abuse, and city officials are upset.

On two occasions, radio transmissions by police investigator Joseph Morrash were blocked in what are believed to be deliberate acts by another officer, because of resentment over Morrash's previous criticism of Public Safety Director Charles T. Strobel and the police department, police officials said.

An officer calling for help in a dangerous situation could be put in jeopardy if his transmissions are"We couldn't talk between any one of those three departments, come hell or high water." -- Charles Kenyon, city official blocked, said Deputy Public Safety Director Arlen Justice. A week ago, the police department opened an investigation to find out who blocked Morrash's transmissions.

The city may spend $10,000 to install monitoring equipment on the present police radio system to prevent further transmissions from being blocked. The new system will be able to monitor transmissions.

At a cost of $75,000, the city has hired Sachs/Freeman Associates, a telecommunications consulting firm, to examine its current radio network and plan an integrated system, known as a "trunked" system, that will allow users to move automatically to open channels, with the help of a computer.

The proposed system would let all city departments communicate with each other and with telephone users, as well, on as many as 11 channels at the 800 megahertz frequency, said transportation chief Kenyon. Mobile radio units in the proposed system may also be equipped with an emergency button that gives the user an override priority when he is in trouble or observes an accident or crime.

Another feature of the new system would be the ability to communicate with other jurisdictions' radio systems, such as in Arlington or Fairfax, according to city documents.

The system also would have a central control board, located at the new public safety center.

"On a day-to-day basis, departments can work on different channels," Kenyon said of the proposed system. "In an emergency, with the central control in a trunked system, you can bind them all together."

During storms or floods a number of departments would have to be coordinated for one emergency, such as fallen trees. Highway maintenance would be called to set up barriers, the recreation department to remove the trees, and the health department might be called to inspect for safety. If a public building was involved, the building inspection department would have to assess the damage.

Often, during emergencies, nervous pet owners ask the city to locate or retrieve stranded pets, so the animal shelter has to maintain radio contact with its field operators, Kenyon said.

Public safety and public works officials from Alexandria are using Arlington County's trunked radio system as a model for their new system. Based on 1984 cost estimates of Arlington's system, Alexandria's radio network could cost $664,300 or more, said Dayton L. Cook, the city's director of Transportation and Environmental Services.