The STI-CO RFMT-NT-V/U/C-QM is a single-port tri-band (VHF, UHF, 700/800 MHz) NMO roof mount antenna kit with a 19.2 in nickel titanium Flexi-Whip, NMO mount, and 17 ft of RG58 coax with a QMA connector installed. It is built for tri-band mobile radios that use a QMA antenna port, most commonly the Motorola APX 8500, and is designed and manufactured in the USA by STI-CO Industries.
Key Specifications
| Frequency Range | 150-174 MHz / 380-520 MHz / 762-870 MHz |
|---|---|
| Bandwidth | 24 MHz / 140 MHz / 108 MHz |
| Typical Gain | 0 dBi (VHF) / 3 dBi (UHF) / 6 dBi (700/800) |
| VSWR | Less than 3:1 |
| Power Rating | 150 W |
| Impedance | 50 ohm |
| Pattern / Polarization | Omnidirectional / Vertical |
| Height | 19.2 in |
| Whip Material | Nickel titanium Flexi-Whip |
| Base | Black thermoplastic, NMO |
| Mount | NMO, 3/4 in through-hole (included) |
| Cable | 17 ft RG58 |
| Connector | QMA, installed |
| Ports | Single port (one cable to one tri-band radio port) |
| Origin | Designed and manufactured in the USA |
Download the STI-CO RFMT-NT-V/U/C spec sheet (PDF)
What's Included
- Tri-band Flexi-Whip antenna (nickel titanium mast on NMO base)
- NMO roof mount
- 17 ft RG58 coax with QMA connector installed
Which Radios Does It Fit?
This kit is terminated in QMA, the snap-on antenna connector used on the Motorola APX 8500 all-band mobile. It works with any tri-band radio that has a single QMA antenna port covering VHF, UHF, and 700/800 MHz.
If your radio uses Mini-UHF, order the STI-CO RFMT-NT-V/U/C, which ships with Mini-UHF by default. If you already have an NMO mount and cable in the vehicle, the RFMT-NT-V/U/C-A mast only is the lower-cost option.
Coverage note for APX 8500 users: this antenna covers 150-174, 380-520, and 762-870 MHz. It does not cover 900 MHz (896-941 MHz) or VHF below 150 MHz. If your system plan uses either, choose an all-band antenna instead.
Why a Nickel Titanium Flexi-Whip?
STI-CO's Flexi-Whip mast is nickel titanium, a superelastic alloy with shape memory. It bends under impact and returns to straight; STI-CO has demonstrated the mast being tied in a knot and springing back to its original shape once untied. On fleet vehicles that means low branches, parking garages, and drive-through canopies are far less likely to leave you with a bent or snapped whip and a detuned antenna, which cuts replacement mast costs and vehicle downtime.
Installation Notes From Our Team
- Mount in the center of a metal roof when possible. Stated gain figures assume a proper ground plane.
- The NMO mount requires a standard 3/4 in hole.
- Route the coax without sharp bends and leave slack at the radio. The QMA plug clicks onto the APX 8500 jack with no tightening; tug gently to confirm it is seated.
- Avoid cutting and re-terminating the cable unless you have QMA crimp tooling for RG58. Coil excess length out of the way instead.
- Check VSWR on each band after installation. The manufacturer specification is under 3:1 across all three bands.
STI-CO installation instructions: sti-co.com/installation-instructions
Frequently Asked Questions
What frequencies does the STI-CO RFMT-NT-V/U/C-QM cover?
It covers 150-174 MHz VHF, 380-520 MHz UHF, and 762-870 MHz 700/800 from a single connection, with typical gain of 0, 3, and 6 dBi respectively.
Is the RFMT-NT-V/U/C-QM compatible with the Motorola APX 8500?
Yes. The APX 8500 uses a QMA antenna connector, and this kit ships with a QMA connector installed on the 17 ft RG58 cable. It does not cover the APX 8500's 900 MHz band.
What is the difference between RFMT-NT-V/U/C, RFMT-NT-V/U/C-A, and RFMT-NT-V/U/C-QM?
RFMT-NT-V/U/C is the complete kit and ships with Mini-UHF by default. RFMT-NT-V/U/C-QM is the same complete kit with a QMA connector. RFMT-NT-V/U/C-A is the antenna mast only, for vehicles that already have an NMO mount and cable.
What is the difference between the STI-CO RFMT-NT and RFMT-TB tri-band antennas?
NT models use STI-CO's nickel titanium Flexi-Whip mast, which flexes and returns to shape after impact. TB models use a stainless steel mast.
Is this a single-port or dual-port antenna?
Single port. One coax cable carries all three bands, so it is designed for tri-band radios with a single antenna port. It is not for use with separate VHF, UHF, and 800 MHz radios.
How much power can it handle?
The antenna is rated for 150 W, which is well above the output of typical public safety mobile radios.
Who makes the STI-CO Flexi-Whip and where is it made?
STI-CO Industries, founded in 1967, designs and manufactures it in the USA at its Orchard Park, New York facility, which is certified to ISO 9001:2015 and AS9100D.
Buy With Confidence From radioparts.com
radioparts.com specializes in land mobile radio parts, antennas, and RF components. Not sure this is the right antenna for your radio or band plan? Send us your radio model and frequencies and we will confirm fitment before you order.
