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Cel-Fi DUO+ 3G/4G/LTE Smart Signal Booster for T-Mobile

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Item Number: 7921



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The Nextivity Cel-Fi DUO+ is the next generation of intelligent repeater kits for home and business users looking to boost their cellular network performance. This LTE signal booster is for T-Mobile network users and works with LTE bands 2, 4 and 12. Each all-in-one cell booster kit can provide high-gain coverage improvements for up to 15,000 square feet.
The T-Mobile Cel-Fi signal booster is completely wireless both in and out. Furthermore, it automatically sets itself up and adjusts itself based on signal strength.
As long as there is at least one bar of signal, the network unit will pick it up and relay the signal to the coverage unit via an encrypted wireless link. A software-based coverage pattern analysis is used to optimize gain. With a peak gain of 100 dBi, it can turn even a weak signal into a robust connection.
The Cel-Fi DUO+ system is designed so it can function around other RF signal emitters or WiFi devices without interference to the booster technology. In addition to self-adjustments for signal, it will also adapt to T-Mobile carrier changes or new equipment installations. Using a Smart T-Mobile signal booster will vastly improve the coverage area even in larger homes and offices, and you won’t need to add antennas or coaxial cables in order for your phones or other devices to benefit from the boosted signal.
With this cell booster, T-Mobile reception can improve at an affordable price and with easy installation. Read a T-Mobile 4G/LTE signal booster review or a 3G T-Mobile signal booster review or two to decide if this device is right for you.
We are ready to answer your questions here by phone or email. Here at 5GStore, we are dedicated to providing the best customer service.

Amplifier Features:

  • Coverage area*: up to 15,000 square feet
  • All-in-One Kit? YES
  • Compatibility: T-Mobile 3G/4G/LTE/AWS (LTE bands 2, 4, 12) ONLY - does not work with other carriers
  • Installation: Cel-Fi doesn't require the installation of external antennas, bulky coaxial cables, handset registration, or a configuration setup by the user. In fact, Cel-Fi intelligently and automatically senses and adapts to its environment-including to changes made by your carrier, or to changes caused by nearby equipment like Wi-Fi, or other Cel-Fi devices. Multiple Units of Cel-Fi can be deployed in large offices and will not interfere with coverage strength.

*Many factors will influence the actual coverage area you will see from a repeater, including layout/floorplan, construction, and original un-amplified signal strength. Depending on your situation, you may see more or less coverage than the estimates listed here. It is not possible to guarantee coverage area.

celfi pro install

Installation notes:

  • There must be at least one bar of usuable signal at the window in which you install the Network Unit. 

Features & Benefits:

  • Wirelessly linked Network and Coverage Units (5GHz U-NII band).
  • Peaceful coexistence with adjacent 802.11( 2.4GHz&5GHz), and femtocell devices.
  • Max EIRP: 10 dBm downlink per 5 MHz and up to 22 dBm uplink, per band.
  • Software-based optimization of integrated antenna coverage pattern which maximizes system gain and provides improved
  • Automatic Gain Control (AGC) based on real-time echo-cancellation.
  • Seamless call handovers between Cel-Fi systems and the macro network.
  • Subscriber devices enjoy improvements in battery life.
  • Bluetooth communications between a mobile handset and Cel-Fi via our Cel-Fi WAVE Mobile App provides software update
    capability and advanced information for technical support.
  • Adaptive signal equalization.
  • Includes Nextivity's 3rd-generation (ARES) chipset with 6 core processor.
  • Up to 3 cellular bands supported; relaying two simultaneously
  • Supports E-UTRA bands 2, 4, and 12 for T-Mobile
  • Support for 3GPP Rel. 10 features.
  • Network-Safe software prevents uplink system gain from exceeding path loss between Network Unit and closest tower,
    thus eliminating unnecessary rise in base station noise level.
  • Uplink Muting Mode automatically shuts down uplink cellular transmissions when no active user equipment is detected.
  • Secure and ciphered provisioning for only T-Mobile’s channels based on network broadcasted PLMN ID.
  • Full Band Scan feature discovers newly deployed and re-farmed spectrum

Package Includes:

  • Network Unit
  • Coverage Unit
  • 2 Power Supplies
  • 2 Mounting Brackets
  • Quick Start Guide


  • RF Specifications:
    • Radio 1: Band 2
      • Frequency DL: 1930-1990 MHz
      • Frequency UL: 1850-1910 MHz
    • Radio 2: Band 4
      • Frequency DL: 2110-2155 MHz
      • Frequency UL: 2110-2155 MHz
    • Radio 3: Band 12
      • Frequency DL: 729-746 MHz
      • Frequency UL: 699-716 MHz
  • Environmental:
    • Operating temperature: 0° to 40°C
    • Storage temperature:-25° to 60°C
    • Relative humidity: 5% to 95%, noncondensing
    • RoHS II 2011/65/EU
    • WEEE (2002/96/EC)
    • ErP 2009/125/EC
  • Power:
    • 12VDC via external supply (two included)
    • External Supply: 100 to 240 VAC, 47-63Hz
    • Power consumption less than 25W per unit
  • Physical Specification:
    • Network Unit: 158.5 x 146 x 59mm, Weight 19.75oz.
    • Coverage Unit: 158.5 x 146 x 59mm, Weight 13.75oz.
  • Standards:
    • FCC Parts 15, 20, 22, 24, 27
    • EN 301 489 -1, 17, 23
    • EN 301 893
    • EN 301 908-1, 11, 15
    • EN 300-328
    • EN 62311
    • UL 62368-1
    • CSA C22.2#62368-1 IEC/EN 62368-1
    • 3GPP TS 25.143 Rel.10
    • 3GPP TS 36.143 Rel.10
    • EN 50566/62209-2/62479 (SAR) Bluetooth SIG

This is a CONSUMER device.
BEFORE USE, you MUST REGISTER THIS DEVICE with your wireless provider and have your provider's consent. Most wireless providers consent to the use of signal boosters. Some providers may not consent to the use of this device on their network. If you are unsure, contact your provider.
You MUST operate this device with approved antennas and cables as specified by the manufacturer. Antennas MUST be installed at least 20 cm (8 inches) from any person.
You MUST cease operating this device immediately if requested by the FCC or a licensed wireless service provider.
WARNING. E911 location information may not be provided or may be inaccurate for calls served by using this device.
Please note, the four largest carriers - AT&T, T-Mobile, Verizon and Sprint - and more than 90 regional carriers have given blanket consent for use of all boosters certified to the new FCC standards.

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All Reviews (9)

Only customers who bought this item from 5Gstore can write a review - these are all verified 5Gstore purchases

Date Added: 10/09/2018 by Brian P. (Bremerton, WA)
Got Verizon signal into building interiors that never had it before.

Date Added: 09/16/2018 by Ted. (SHELBY TOWNSHIP, MI)
Works great for 700mhz band on T-Mobile!

Date Added: 04/06/2018 by Randall R. (Rocky River, OH)
Seemed to improve the signal significantly for us to use air cards in our new warehouse while we wait for our network to be installed.

Date Added: 11/22/2017 by Jackie H. (Wausa, NE)
Works as advertised. Where we were getting 1x service we now get 3 & 4 bars LTE.

Date Added: 07/31/2017 by Richard M. (Westlake Village, CA)

Date Added: 07/24/2017 by Brad J. (Dunmore, PA)
not the best for commercial buildings. The range advertised is definitely for open spaces and not buildings with walls. The signal drops off fast beyond 75 feet and they seem very directional in that the faces of the units need to be pointed at each other. We are seeing a small improvement but not as good as I had hoped.

Date Added: 11/08/2016 by Glinda G. (Covington, LA)
This product does what we needed it for. To boost cellphones in our office which
did not have very good reception.

5Gstore Comments:
Thanks for your feedback! It looks like you might have selected 1 star when you meant to select 5, since everything is working out well :) But let us know if there's anything we can help you with!

Date Added: 10/11/2016 by Anonymous 5Gstore Customer
I've used several competitors solutions That was not by choice unfortunately. I started with the zBoost which was a disaster trying to prevent oscillation (to close / to far) and never produced any real tangible results after a TON of effort. I then moved to the weBoost which was marketed under another name when I bought it from Wilson but the hardware is identical. It was a definite step forward but where I live with 1 bar starting out it really didn't get me where I needed to be and again I'm running co-ax cable all over the place. Just bought the Cel-fi Duo+ for Verizon 2 weeks ago and it is the first signal boosting product to genuinely meet my expectations. I went from 1 bar to a solid 3 bars now on the phone, data speeds jumped to between 6-10mbps both down and uploading from 3down/0.3up before the booster and calls no longer breakup. I've noticed calls sound different sometimes now too and I believe that Verizon's Voice over LTE now works because I have enough signal to do it. Also of note, this boosts 100dB whereas I think the others are 50dB and 60dB.

So yeah, the results were good. The real kicker is the install was great. There basically is no install compared to the work needed for the other boosting options. You plug the antenna box into a power outlet where the signal is strongest (I have mine sitting on the window sill). Then you go towards the other end of the structure and plug in the amplifier box. No co-ax from an outside antenna. No co-ax between the 2 units. Just 2 boxes that plug in. There's an easy to read LCD that tells you closer or farther and a signal number that goes up or down to help with placement. Soooo much easier. Getting ready to buy another one of these for my office. Coverage area is great, definitely no issues anywhere in my 2400sq ft home.

Date Added: 07/21/2016 by Tom. (Schaumburg, IL)
Cel Fi performs exactly as advertised.

I have customers who have been waiting for this solution for a while. The area I support from a technical perspective is Health Care. Hospitals have always been notorious for poor in building coverage. DAS is very expensive and network extenders require a GPS fix and back haul.

The Cell fi performed as good and better than I had anticipated. First test out of the box was at home and in my basement where there was no 4G coverage ever, within 5 minutes of unpacking the 2 boxes and plugging them in I had over 8 Mbps down and 1.7 Mbps up. Next day, I visited a customer (hospital) with a common issue. We were unable to get a GPS fix as the location was too far from a window or GPS signal to get the network extender to activate. Again, in record time (this is simple to set up and takes literally minutes to work) the room was filled with notification sounds of text messages coming in to Mobile phones for the very first time. They were ecstatic. The network security resource reported that no rogue devises popped up on his diagnostic tool and he cleared the device for purchase.

My final check for the week was at an airport for Emergency Services Flight for Life where signal issues persisted, again, a significant improvement in speed test results and coverage. The only issue was the inability to pass signal through a Physical Firewall separating the Hanger from the dispatch offices where cinder block and whatever else was used in the building construction. It was not a deal breaker, just needed 2 sets of boxes for each area on either side of the brick fire wall.

Affordable, childs play to install, and it works great. I enthusiastically endorse and recommend giving this a try where not having coverage. Is not an option. Thanks to my friends and solid resources at 3G store for Cell Fi and all they do every day.

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