The Project 25 Technology Interest Group (PTIG) is pleased to share our latest P25 System of the Month:

Oklahoma’s PatrolNet P25 Network

 The docvument can be downloaded using this link: https://www.project25.org/index.php/documents/ptig-p25-system-case-studies?view=frontlist&catid[0]=10015

The Oklahoma Department of Public Safety (DPS) has implemented PatrolNet, a Project 25 (P25) conventional network that covers about 210,000 square miles in Oklahoma.

DPS oversees the Oklahoma Highway Patrol (OHP), which staffs 1,500 civilian and uniformed employees across the state. OHP state troopers patrol the state’s 111,994 miles of state roads and highways, responding to traffic collisions, natural disasters, and civil disorders.

DPS had an aging VHF low-band system with spotty coverage across about one-third of the state. Maximizing Oklahoma DPS’ current sites, Stolz Telecom designed a coverage plan for a new P25 network using 35 sites and covering one-third of Oklahoma. To address the coverage problems with the legacy system, the department deployed an in-fill 700 MHz voted multicast coverage solution designed by Stolz Telecom and using Tait Communications P25 equipment in 2021.

The department has a Communications & Electronics Services Team that oversees and maintains its public safety communications network. That DPS team independently verified Stolz Telecom’s coverage calculations and assumptions. The new P25 base stations have remote access and spectrum analyzer capabilities, allowing DPS field technicians to remotely diagnose issues in real-time. This saves hours of driving time to remote locations that are sometimes five hours away.

The solution was cost effective, with the radio equipment, configuration, and training providing a solution that easily fit within the DPS budget. The infrastructure cost was about $1.5 million. The Communications & Electronics Services Team installed the shelter hardware and hired a tower crew to purchase and install the tower hardware for a separate cost.

The P25 conventional network includes three sites, two channels, a console gateway, and an RF console. The base station can operate in a trunked  network in single, simulcast and fill-in receiver configurations. The mobile station votes each downlink frequency to find the best frequency available.

Stolz Telecom provided engineering support to configure the network and train the internal technicians for ongoing maintenance and firmware upgrades.

System Expansion

Texas County is in the panhandle of Oklahoma. The county seat is Guymon, and the population was 21,384 in 2020. Texas County is the second-largest county in Oklahoma based on land area and is named for the state that adjoins the county to its south.

The county includes 11 fire departments, 8 law enforcement agencies, and 2 ambulance services.

The county joined the DPS P25 conventional network in 2024 through an inexpensive equipment purchase. The tower equipment and first round of radios were funded with American Rescue Plan Act (ARPA) money. P25 radios from at least two different vendors are being deployed. Additional P25 radios are being purchased using grant funds, and more radios will be budgeted into yearly budgets.

To ensure coverage would be adequate, hundreds of miles of drive coverage testing were conducted, and the results exceeded expectations.

The three tower sites in Texas County cover most of the Beaver and Cimarron County Oklahoma, and reach into five counties in Texas, one in Colorado, and five counties in Kansas.

The green portable symbols are portable coverage, and the mobile symbols that are green indicate mobile coverage.

Network Advantages

One of the benefits for Texas County to join PatrolNet in addition to meeting its budgetary requirements is improved coverage. The network offers clear radio traffic and 700 MHz portable coverage tested at nearly 100% countywide. Previous VHF portable coverage was 5 miles or less. Officer safety has benefited.

Network redundancy is another benefit through generators at state-owned tower sites. Texas County towers lacked generators at 3 of 5 previous sites, but DPS 700 MHz towers all have generators.

In addition, interoperability has improved. Joining PatrolNet allowed the county to restore communications with Kansas after the state moved to 800 MHz. Texas County mutual aid with Kansas EMS providers and fire departments is common, so renewed interoperability was critical.

Direct communications with the Oklahoma Highway Patrol and local agencies was also established. The 700 MHz system will play a key role in communicating with neighboring counties and allow a future COOP plan. There are currently no radio communications with the two surrounding counties, but testing has proven the new system will fill this gap.

Lessons Learned

Rural areas pose unique coverage challenges. Because of smaller budgets, rural agencies must maximize coverage with effective network design, which is critically important to a successful P25 mission-critical communications system.

Working with state partners to share infrastructure provides cost benefits to both entities and allows for true radio communications interoperability between state and local agencies.

Achieving buy-in from local agencies to change spectrum bands from VHF to 700/800 MHz was a challenge. Stolz Telecom demonstrated the new frequencies’ improved coverage with propagation maps and a live demo of the PatrolNet system.