Uniden UM50 FN FirstNet Large Vehicle Cell Signal Booster | 7021FN-LV

Uniden UM50 FN FirstNet Large Vehicle Cell Signal Booster

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  • Mobile public safety signal booster for first responder vehicles
  • Amplifies 700 MHz FirstNet band 14 & AT&T band 12
  • Your choice of high-gain whip antenna, inc. a model with a quick-release mount
  • Stainless steel “bull bar” antenna mount folds down quickly & easily for low-clearance areas or vehicle storage
  • Improves signal for up to 20 phones in the same vehicle
  • Includes 12V DC socket power supply & 12V DC hardwire power supply


Free lifetime support
SKU: 7021FN-LV

Product Description

This product has been discontinued. Please see our other mobile cell signal boosters.

Features of the Uniden UM50 FN for Large Vehicles

  • Combines Uniden’s FirstNet mobile cell phone signal booster with a high-gain whip antenna for the best possible signal on the road.
  • Provides emergency cellular communications for police, fire, and medical personnel in cars, trucks, and other vehicles.
  • Works with AT&T’s FirstNet cellular network.
  • The Uniden booster installs easily under your seat or in any other convenient, well-ventilated spot. Mounting holes allow you to secure the booster to drillable surfaces.
  • Your choice of outside antenna:
  • Standard: The RFI 26″ whip antenna has 4.5 to 5.5 dBi of gain and has 16.4′ of attached RG58 coax cable.
  • Optional upgrade: The RFI 38″ quick‑release whip antenna has 4.5 to 6.5 dBi of gain and a quick-release feature for fast and easy storage. It also includes 16.4′ of attached RG58 coax cable.
  • The fold-down “bull bar” mount lays the whip antenna flat for low clearance or storage. The mount operates instantly with a spring‑loaded pin and includes a stainless steel 3‑way rail mount.
  • Includes a 12V DC socket power supply and a 12V DC hardwire power supply—use whichever power supply meets your vehicle’s needs.
  • Boosts service for voice, text, and data.
  • Boosts cell signal for multiple users simultaneously.
RFI FBBM-B Folding Bull Bar Mount for OTR Antennas TS432702 RFI’s “bull bar” mount for whip antennas lets you lay the antenna flat instantly with a spring‑loaded pin. (Click to enlarge.)

FirstNet is a high-speed, nationwide wireless broadband network maintained by AT&T for public safety communications. This network has dedicated cellular frequencies for law enforcement, firefighters, ambulances, and other first responders and public safety agencies.

The Uniden UM50 FN cell phone signal booster helps you stay connected and experience fewer dropped calls, undelivered texts, and missed email messages at all times, including during emergencies. It amplifies FirstNet band 14 and AT&T band 12.

Powerful Signal’s UM50 FN system for large vehicles includes an RFI OTR whip antenna that provides 4.5 to 6.5 dBi of signal gain, sending up to 4½ times the signal to the booster so you can stay connected, experience fewer dropped calls and missed messages, and have more reliable access to navigation and other apps on your smartphone.

Stay connected farther from cell towers and experience fewer dropped calls, undelivered texts, and missed email messages. Data-driven navigation and other apps will perform better in remote areas with weak cell service and obstructions between your car and the cell tower.

Who is the Uniden UM50 FN for Large Vehicles for?

  • Police departments, sheriffs, and other law enforcement agency trucks and vehicles.
  • Fire trucks and ambulances.
  • Personal vehicles used by police chiefs, fire chiefs, and other key personnel who need improved FirstNet reception on the road.
  • First responder vehicles operating in remote locations with weak cell service (new communities, rural areas, etc.)


Installation of the Uniden UM50 FN can be completed in about 30 minutes.

  • Attach the stainless steel 3‑way mount to a rail or bracket in a location that will provide the whip antenna with the clearest 360° field of view. Secure the bull bar mount to the 3‑way mount with the threaded bolt.
  • Thread the cable connected to the whip antenna’s spring mount through the opening at the top of the bull bar mount. Secure the antenna to the bull bar mount with the jam nut.
  • Run the RG58 coax cable inside to the booster unit. If you run the cable through a door, thread it through and behind the doorway’s weatherstripping, securing the cable where needed to keep it from flailing in the wind. Connect the end of the cable to the booster. Do not pinch, kink, loop, or coil the cable.
  • Place the Uniden UM50 FN booster under a seat or in another location where it will have adequate ventilation.
  • Adhere the dash-mounted inside patch antenna as close as possible to where you keep your phone while driving. For example, if you dock your phone in a cradle on the dashboard, the server antenna should be mounted to the dashboard right behind the cradle. (The closer the server antenna is to the phone, the more likely you are to receive improved signal when outside reception is very weak.)
  • Run the inside antenna’s RG174 coax cable to the booster and complete the connection.
  • Plug in the booster using the DC socket power supply or the DC hardwire power supply.
Uniden UM50 FN FirstNet large vehicle cell signal booster setup diagram Typical setup of the Uniden UM50 FN large vehicle booster (click to enlarge)

Uniden UM50 FN for Large Vehicles kit contents

This is a complete kit, with everything you need to start getting the best signal in your vehicle:

Uniden UM50 FN booster 7021FN icon Uniden UM50 FN cell signal amplifier 7021FN
LTE Vehicle Antenna RFI 26-Inch Whip 5.5 dBi 698–2700 MHz TS210513 CD7194-B fiberglass whip antenna icon RFI 26″ black fiberglass whip antenna w/attached spring mount & 16.4′ black RG58 coax cable CD7194‑B
RFI Folding Bull Bar Mount for OTR Antennas TS432702 icon RFI bull bar antenna mount w/nut & washers TS432702
Stainless Steel Rail Mount for RFI Folding Bull Bar Antenna Mount TS432111 icon Stainless steel 3‑way mount TS432111
Uniden UM50 FN patch antenna icon Adhesive‑mount inside patch antenna w/10′ RG174 coax cable
Uniden UM50 FN 12V DC/DC power supply icon 12V DC/DC power supply w/1′ coiled cable (extends to 4′ max)
Uniden UM50 FN 12V DC hardwire power supply icon 12V DC hardwire power supply w/10′ cable & inline fuse
Uniden UM50 FN magnetic-mount antenna icon Magnet‑mount outside antenna w/10′ RG58 coax cable (not used w/whip antenna)
LTE Vehicle Antenna RFI Q-Fit 38-Inch Whip 6.5 dBi 698–2700 MHz TS210701 CDQ7195-B fiberglass whip antenna icon Optional upgrade
RFI Q‑Fit 38″ black fiberglass whip antenna w/quick release spring mount & 16.4′ black RG58 coax cable CDQ7195‑B

Works with the AT&T FirstNet network

The Uniden UM50 FN FirstNet booster system works only on AT&T’s FirstNet cellular networkexternal link icon, which includes two bands of frequency:

  • Band 12 (uplink 699–716 MHz; downlink 729–746 MHz).
  • Band 14 (uplink 788–798 MHz; downlink 758–768 MHz).

It does not boost signal for other cellular networks or frequencies.

Not sure which bands your phone uses? Contact us—our technical support reps will be happy to help you!

FirstNet logo with other carrier logos crossed out The FirstNet logo is a registered trademark of FirstNet, an independent authority within the U.S. Department of Commerce.

FCC notice

The Uniden UM50 FN is classified by the Federal Communications Commission (FCC) as a Part 90 Class B wideband industrial booster. To operate a UM50 FN booster you must obtain the express written consent of AT&T and register the booster with the FCC. Licensing and registration is the responsibility of the booster owner/operator; Powerful Signal cannot license boosters on behalf of its customers. Click here for more information on Part 90 boosters.

Prop 65 notice

Caution triangle icon Warning This product can expose you to chemicals, including nickel, which is known to the State of California to cause cancer, and Bisphenol A, which is known to the State of California to cause birth defects or other reproductive harm. For more information go to link icon.

Product Specifications

Auto/pickup truck/SUV
Outside Antenna:
Omnidirectional whip / omnidirectional magnet-mount
Inside Antenna:
Omnidirectional low-profile
Cable Type:
RG58 / RG174
Connector Type:
50 Ω
+50 dB max
Max Output Power (Uplink):
≥17 dBm
Max Output Power (Downlink):
0 dBm
Booster Case Material:
Signal Readout:
LED lights

Warranty Information

For warranty information on this product, please see our Uniden warranty information page.

Questions & Answers