Operating Manual MHX-910A 900 MHz Spread Spectrum OEM Module Revision 0.10, November 1, 2004 Microhard Systems Inc. #17, 2135 - 32nd Ave. N.E. Calgary, Alberta T2E 6Z3 Phone: (403) 248-0028 Fax: (403) 248-2762 www.microhardcorp.
Warranty Microhard Systems Inc. warrants that each product will be free of defects in material and workmanship for a period of one (1) year for its products. The warranty commences on the date the product is shipped by Microhard Systems Inc. Microhard Systems Inc.’s sole liability and responsibility under this warranty is to repair or replace any product which is returned to it by the Buyer and which Microhard Systems Inc. determines does not conform to the warranty.
Regulatory Requirements WARNING To satisfy FCC RF exposure requirements for mobile transmitting devices, a separation distance of 23 cm or more should be maintained between the antenna of this device and persons during device operation. To ensure compliance, operations at closer than this distance is not recommended. The antenna used for this transmitter must not be co-located in conjunction with any other antenna or transmitter. WARNING This device can only be used with Antennas listed in Appendix A.
Contents CONTENTS .............................................................................................................................................................. III HISTORY....................................................................................................................................................................V TABLES AND FIGURES .......................................................................................................................................
History Revision Date Action 0.10 2004-11-01 Created MHX 910A Operating Manual: History FW Rev.
Tables and Figures Tables Table 1 Path Loss ..........................................................................................................................................................8 Table 2 Cable Loss ......................................................................................................................................................10 Figures Figure 1 Gain Calculation..........................................................................................................
1. Introduction 1.0 Product Overview The MHX-910A is a very high-performance wireless module. When used properly very long distance communication at very high speeds can be accomplished. The MHX-910A operates in the 902 - 928 MHz ISM band, using frequency-hopping spread-spectrum module is capable of providing reliable wireless data transfer between almost any equipment which uses an RS232, RS422, or RS485 interfaces.
1.1 Features Key features of the MHX-910A include: transmission within a public, license-exempt band of the radio spectrum1 – this means that it can be used without access fees (such as those incurred by cellular airtime); Transparent, low latency link providing true 115.2 kbps continuous throughput Communicates with virtually all PLCs, RTUs, and serial devices through RS232, RS422 and RS485 interface 3.
MHX 910A Operating Manual: Chapter 1 Introduction 3
2. Configuration 2.0 Overview This chapter provides a detailed description of the various operating parameters of the MHX-910A. 2.1 Output Power Level The Output Power Level determines at what power the MHX-910A transmits. The MHX-910A’s sensitive receiver can operate with very low power levels, so it is recommended that the lowest power necessary is used; using excessive power contributes to unnecessary “RF pollution”.
WARNING In order to comply with the FCC/IC adopted RF exposure requirements, this transmitter system will be installed by the manufacturer's reseller professional. Installation of all antennas must be performed in a manner that will provide at least 23 cm clearance from the front radiating aperture, to any user or member of the public. IMPORTANT: FCC Regulations allow up to 36 dBi effective radiated power (ERP).
3. Installation 3.0 Overview The installation, removal or maintenance of all antenna components must be carried out by qualified and experienced personnel. The MHX-910A complies with FCC part 15 at the modular level for operation in the license-free 902-928 MHz ISM band. This chapter provides guidelines for installing and deploying equipment which incorporates the MHX-910A module. 3.
The power level has been set to 30dBm (1W) on the transmitter, and the receiver sensitivity for the MHX-910A is -105dBm. System gain can be calculated: Base Height (m) 30 - 2 + 6 + 3 - 2 + 105 = 140 dB. Mobile Height (m) Distance (km) Figure 2 System Deploying When deploying your system, care must be taken to ensure the path loss (reduction of signal strength from transmitter to receiver in dB) between equipment does not exceed the system gain (140 dB in the above example).
3.2 Internal Cabling This section describes the recommended procedure for installing cabling and antennas for use with the MHX-910A module. The most common method for installing the module is to run a cable from the module’s MCX connector to a reverse TNC bulkhead connector on the chassis of the equipment as shown in Figure 3. This cable can be purchased from Microhard Systems.
3.3 Installing External Cables, Antennas and Lightning Arrestors WARNING To satisfy FCC RF exposure requirements for mobile transmitting devices, a separation distance of 23 cm or more should be maintained between the antenna of this device and persons during device operation. To ensure compliance, operations at closer than this distance is not recommended.
Factors to take into consideration when choosing a cable are: • price; • bend radius limitations (the lower performance cables generally can bend more sharply) • performance requirements; and, • distance between the equipment and the antenna. When installing the cable, always begin fastening at the top near the antenna connector/surge arrestor. The cable must be supported at the top with a hose clamp or wrap lock, and at 5 ft intervals down the length of the tower.
Antenna Before choosing an antenna, you should have some knowledge of the path loss and the topology of the equipment. If the equipment is in a fixed location and is to communicate with only one other unit also in a fixed location, then a Yagi antenna is suitable. Choose a Yagi with enough gain to ensure adequate gain margin. When deploying the Yagi, point the antenna towards the intended target, ensuring the antenna elements are perpendicular to the ground for vertical polarization.
Examples: FCC and Industry Canada Regulations allow up to 36dBm effective radiated power (ERP). Therefore, the sum of the transmitted power (in dBm), the cabling loss and the antenna gain cannot exceed 36dBm with respect to the isotropic radiator.
14 MHX 920 Operating Manual: Chapter 3 Installation
A. Approved Antennas Group Part Number Description Quarter Wave MHS031010 <1.5dBi, 900MHz 1/4 Wave Antenna Reverse SMA Right Angle MHS031020 <1.5dBi, 900MHz 1/4 Wave Antenna Reverse SMA Straight MHS031030 <1.5dBi, 900MHz 1/4 Wave Antenna Reverse SMA Right Angle MHS MHS031040 <1.5dBi, 900MHz 1/4 Wave Antenna Reverse SMA Straight MHS MHS031050 <1.5dBi, 900MHz 1/4 Wave Antenna MCX Right Angle MHS MHS031060 <1.
16 MHX 910A Operating Manual: Appendix A Approved Antennas
