
Vaisala Portable Antenna Set CG31
Features and benefits
▪ 
▪
The Vaisala Portable Antenna Set 
CG31 is a portable antenna designed 
to be used with GPS wind-nding 
systems. The antenna set consists 
of a Helix UHF antenna with antenna 
amplier and GPS antenna on a 
tripod. The antenna set is painted 
green as standard. One person can 
handle and assemble the antenna set.
The CG31 receives radiosonde signals 
in 400 MHz meteorological UHF band. 
The tripod and the antennas fold 
compactly for transportation. 
The transport case is made of 
polypropene and equipped with 
wheels for ease of transportation. 
The transport case also holds an 
equipment bag, which contains foot 
pads, pegs and a hammer.
www.vaisala.com
Easy set up with captive parts
Long telemetry range - 150 km 
with RS92-SGP 
Vaisala portable antenna CG31 is easy to set up and is well suited for portable 
installations.

Technical data
UHF Antenna
Type Full-wave Quadrifilar Helix 
Frequency range 400 … 406 MHz 
Gain (Elevation angle 25°) 3.5 dBic 
Polarization Right-Hand Circular 
Horizontal pattern Omnidirectional
Telemetry range
With RS92-SGP radiosonde 150 km
Amplifier
Gain 20 dB typical 
Noise figure   <2 dB 
Power input   +10 … 12 VDC, 
typically 130 mA through RF cable 
Output impedance 50 ohms, VSWR <1.5
GPS Antenna
Primary power  + 5 volts DC (± 10%) 
Power consumption  22 mA, 0.11 watts (nominal) 
Output impedance 50 Ohms 
Frequency L1 (1575 MHz) 
Polarization Right-Hand Circular
Polarization (RHCP) 
VSWR 2:1 
Axial ratio  2 dB at zenith, 10 dB above 10° elevation 
Gain 35 dB (nominal) 
Noise 2.75 dB (nominal) 
Pass-band width 50 MHz 
Azimuth coverage 360° (omni-directional) 
Elevation coverage 0° to 90° elevation
(hemispherical)
Mechanics
Connector
UHF Antenna  Coaxial N-type female
GPS Antenna Coaxial TNC-type female 
Diameter Footprint 1133 mm 
Total height assembled  1695 mm 
Weight
With cables 10.5 kg
With accessories and transport case 23 kg 
Transportation case dimensions 1380 x 355 x 385 mm 
Standard cable length 20 m
Environmental conditions
Operating temperature range -40 ... +55 ºC 
Operation humidity range 0 ... 100 %RH 
Operating precipitation Unlimited 
Maximum wind speed 65 m/s 
Storage temperature -50 ... +71 ºC 
Storage humidity 0 ... 100 %RH
For more information, visit 
www.vaisala.com or contact 
us at sales@vaisala.com
Ref. B210687EN-D ©Vaisala 2010
This material is subject to copyright protection, with all 
copyrights retained by Vaisala and its individual partners. All 
rights reserved. Any logos and/or product names are trademarks 
of Vaisala or its individual partners. The reproduction, transfer, 
distribution or storage of information contained in this brochure 
in any form without the prior written consent of Vaisala is strictly 
prohibited. All specifications — technical included — are subject 
to change without notice.