Wavenet Technology BM28001 Wireless OEM Modem Module User Manual 2 6
Wavenet Technology Pty Ltd. Wireless OEM Modem Module 2 6
Contents
crn24348 antenna
Installation ________________________________________________ Boomer II User Manual & Integrator’s Guide
Wavenet Technology 42 BM210012WT26
Selecting an Antenna
The requirements for the antenna used with the Boomer II OEM
Modem are:
Antenna Gain: 1 dBi (isotropic) maximum average gain
if module FCC approvals are to be used
without separate equipment approval for
the host product.
Impedance: 50Ω
Centre Frequency: 833MHz ± 5MHz
Frequencies of operation: 806 to 825MHz (transmit)
851 to 870MHz (receive)
Acceptable return loss: VSWR < 1.5 or RL < -14dB (recommended)
VSWR < 2.0 or RL < -10dB (minimum)
The power output of the Boomer II OEM Modem is nominally 1.8W at
the antenna port. The antenna gain or loss will affect this value.
Connecting the Antenna
The Boomer II OEM Modem Module provides an MMCX RF
connector located at the top of the unit, to attach to the antenna cable.
The antenna does not plug directly into the modem but uses an antenna
cable to interface between the device and the modem.
The antenna cable should be a low loss, 50Ω impedance and have a
MMCX plug that can mate with the modem’s MMCX socket
(82MMCX-S50-0-2). It is recommended that a Huber+Suhner
connector be used to connect to the modem as below:
q 11 MMCX Straight Connector
q 16 MMCX Right Angle Connector
If an extension cable is required to the antenna, it should be low loss, as
short as possible and an impedance of 50 ohms. Proper matching
connectors should be used, as each connector introduces a return loss
and reduces performance.
Positioning the Antenna
Positioning the antenna will affect the gain provided by the antenna.
The antenna should be orientated so that it provides vertical
polarisation as the DataTAC network is based on vertically polarised
radio-frequency transmission.
The antenna should be located as far from the active electronics of the
computing device as possible. Typically, a metal case of a computing
device and its internal components may attenuate the signal in certain
directions. This is undesirable as the sensitivity and transmit
performance of the Boomer II would be reduced. However, careful use
Boomer II User Manual & Integrator’s Guide _________________________________________________Installation
BM210012WT26 43 Wavenet Technology
of metal used for the ground plane for an antenna can improve the
antenna gain and the coverage area for the system.
If your device is designed to sit on a surface, the antenna should be
positioned as far from the bottom of the device as possible. This is to
reduce the radio frequency reflections if the device is placed on a metal
surface.
If your device is hand held or is worn next to the body, the antenna
should be positioned to radiate away from the body.
The integrator should refer to the statement of Compliance on page 12
of this manual and Regulatory Requirements section on pages 23-27
for country requirements.
SAR Routine Function
The modem complies with OET Bulletin 65 and Supplement C (Aug
1997) for FCC Specific Absorption Rate (SAR) requirements. A SAR
limiting function is available for end user applications to limit the
average transmitted power by preventing new user data transmissions
until the previous period’s average transmitted power is less than the
required SAR level.
During all transmission times a Retransmit Delay Accumulator is
incremented by a value of:
time Td = Duty Factor constant x actual time of block.
The Duty Factor is a ratio of non transmit to transmit time:
= (100 – DutyCycle%) / DutyCycle%
When the current data block and any retries have been sent, the next
user data transmission is inhibited, dependent on the required duty
cycle and the last transmission time. User data to be transmitted will be
accumulated in a data buffer.
When not transmitting, the Retransmit Delay Accumulator decrements
until the timer has expired.
The transmit may restart again, if there is data to send.
The default setting of the modem is 10% Duty Cycle unless otherwise
programmed in the factory at the time of modem manufacture. Once set
in the factory the user has no ability to change this value to ensure
compliance with FCC SAR requirements.