A3LA-RG Guide Version B
Document Number: 451-93156-009B
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RIDIUM
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NTENNA
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ONNECTOR
The A3LA-RG modem uses a single TNC female 50-ohm connector for both transmit and receive
). Cable loss between the modem and the antenna is critical and must be kept less
than 3 dB at the operating frequency of 1616 to 1626.5 MHz. The minimum link margin of 12 dB
must also be maintained. General Radio Frequency (RF) parameters are listed in Table 2 below.
Table 2: General RF Parameters
Type
Description
Frequency Range
1616 to 1626.5 MHz
Input/Output Impedance 50 ohms
Oscillator Stability
±1.5 ppm
NAL Research offers several types of antennas for use with the A3LA-RG modem. These
antennas include the fixed mast, mobile magnetic/permanent mount, and portable auxiliary.
For low cost and applications where small form-factor and light weight are required, NAL
Research recommends model SYN7391-C. If the specific application requires a custom antenna,
it must meet the specifications below.
Table 3: Antenna Specifications
Parameter
Value
Operating Temperature Range
–40°C/+85°C without loss of function
Measurement Frequency Range 1616 to 1626.5 MHz
VSWR
< 1.5 : 1
Maximum Gain
3 dBiC
Nominal Impedance
50 ohms
Polarization
Right-handed circular (RHCP)
Basic Pattern
Omnidirectional and hemispherical
Satellite signal strength reported by the A3LA-RG when issuing an AT+CSQ command indicates
the signal strength of the ring channel. Be careful when using this signal reading for
comparisons between devices. Of particular note are the following:
There is a 0.5 dB tolerance on the calibration.
