In real estate, city views and other prime locations get top dollar because they’re scarce. With police cruisers, ambulances and other first responder vehicles, the roof is beachfront property.
A vehicle’s roof is the ideal spot to mount cellular, GNSS, Wi-Fi and other antennas because the metallic surface serves as their ground plane. The size of that surface and the antennas’ locations within it directly affect their gain, which measures an antenna’s directionality as it relates to the strength of the signal that it’s transmitting or receiving. (For an overview of gain and related concepts, see “Understanding Ground Planes for Cellular and GNSS Devices.”)
The roof of an ambulance or a police SUV might seem like plenty of real estate for multiple antennas, but that’s often not the case. Take the example of the Ford Police Interceptor, one of North America’s most widely used first responder vehicles. The roof panel has a dozen raised “ribs” that make it challenging to find room for cellular, GNSS and other antennas. It’s also advisable to keep the antennas a half wavelength away from the light bar in case any of its components generate RFI.
These challenges are why upfitters and other companies that specialize in public safety communications say they often spend three to four hours per vehicle drilling holes in multiple roof locations and then fishing cable to each one. When a client has a fleet of dozens or hundreds of vehicles, the installation time quickly adds up.
And that’s assuming those specialists can find antenna models that meet all of the client’s technology and performance requirements and in form factors that fit between ribs and other obstructions. Each antenna enclosure must sit tight against the roof to prevent humidity and water from seeping in and damaging the cables, cable connectors and antenna elements. This is mission-critical communications, after all.
18 Antennas for Broadband, Navigation, Telemetry and Voice in a Single Svelte Enclosure
To overcome these challenges, Taoglas recently launched the Patriot series, a compact, multi-function roof-mount antenna designed for first responder fleets. Measuring just 205 mm long by 180 mm wide, a single Patriot enclosure accommodates up to 18 antenna elements for:
- 4G and 5G cellular, including FirstNet (600-6000 MHz)
- Dual-band GNSS (L1 and L1/L5) and a secondary GNSS (L1)
- Wi-Fi (2.4, 5.8 and 7.1 GHz)
- SDARS (2.3 GHz)
- LMR/TETRA (380-400 MHz and 700-900 MHz)
A dedicated whip element with full P25 VHF/UHF/700-900 MHz support also is available. The whip varies between 60 mm and 164 mm, depending on frequency requirements.
With the Ford Interceptor, for example, installers simply remove the existing OEM shark fin antenna and replace it with the Patriot. This minimizes the need for drilling more, or even any, new holes. The Patriot series includes a custom-engineered foam gasket to ensure a perfect seal between the antenna and the curved vehicle roof.
In addition to reducing installation time to under an hour, the Patriot saves money in the long run because first responder agencies no longer have dozens of roof holes to seal to prepare their retired vehicles for sale. Considering how perpetually tight public safety budgets are, every dollar counts.
The Patriot Antenna can be pre-ordered through GetWireless now.
