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RFI CD51-68-50 UHF Ground Independent Mopole Antenna (450-520MHz) - MBC Base

RFI CD51-68-50 UHF Ground Independent Mopole Antenna (450-520MHz) - MBC Base

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RFI CD51-68-50 UHF Ground Independent Mopole Antenna (450-520MHz) - MBC Base

The CD50/CD51 Series UHF ground independent Mopole antennas are versatile and popular antennas, providing excellent performance in virtually any mounting position.

When the CD50/CD51 gets mounted on a vehicle gutter or similar position, these UHF Mopoles provide optimum performance with a largely omni-directional pattern. Due to the low angle of radiation inherent in the dipole antenna pattern, a 4.0 dB improvement in performance is typical when compared to a 3 wave whip in the centre of a metal roof.  

The end fed design of the UHF Mopoles incorporates a truly unique transformer in the base section. In this patented feed assembly, the dielectric of the coaxial feeder cable is trimmed to a set length and then introduced into the coil in termination. The result is a precisely matched feed which is so consistent that tuning to frequency from a chart becomes a matter of course.

- CD51 antennas are fitted with a flexible nylon radome over a copper element - ideal in industrial applications. 
- CD50 antennas have an elegant and durable tapered stainless steel whip section.

There are two styles of mounting arrangements offered. The CD50-xx-70 and CD51-xx-70 versions mount via a threaded stud and nut assembly. The antenna can be easily terminated, tuned and re-terminated in the field using the instructions supplied. Its patented design allows the coaxial cable to be replaced in the field without specialised tools or soldering.

The CD50-xx-50 and CD51-xx-50 versions mate with the MBC coaxial base providing an internal, permanent connection in a completely sealed unit. The MBC base is easy to install and allows the entire antenna to be removed and replaced at will.

• Versatile - Ground plane independence allows alternative mounting locations
• Performance - High performance and largely omni-directional pattern when not centre roof mounted
• Convenient - Patented design allows termination or retermination in seconds
• Stainless steel whip or flexible nylon whips cater to individual needs
• Durable - Base coil is virtually indestructible
• Unique transformer design
• Australian Patents #596830 and #656793

(Note 1) Mopole™ antennas such as the CD50 and CD51 exhibit a 4dB improvement in performance over a ¼ wave whip but in pattern tests deliver only 2.0 to 2.5dB of actual gain. This improvement in performance can be attributed to a lower angle of radiation and is of particular benefit to users in rugged terrain conditions and in heavily built up city areas.
(Note 2) Available pre-terminated with 5m RG58. Use -73 or -53 suffix to replace -70 or -50 suffix.


Specifications: CD51-68-50

Band 380 - 440MHz
Tunable Bandwidth 13 MHz @ <1.5:1 VSWR
Nominal Gain dBi 4
Tuning Field tune to minimum VSWR using supplied tuning chart
Power W 50
Cable and Connector Not included, order separately. See note (2)
Whip Material Copper braid element in flexible nylon tubing
Suggested Installation Bracket
Whip Length mm 360
VSWR 13 MHz @ <1.5:1 VSWR
Mounting MBC Base (Included)



CD51-68-50 Technical Data Sheet