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n920 Operating Manual

 

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Once the equipment is deployed, you can verify the signal strength by 
entering into Command Mode and reading Register S123.  This register 
provides the average signal strength in dBm.  The minimum strength for 
communication is roughly -108dBm.  For consistent reliable 
communication, you should try to deploy the equipment such that signal 
strength exceeds -95dBm. 

 

3.2  Antennas and Cabling 

This section describes the recommended procedure for installing cabling 
and antennas for use with the N920 module. 

3.2.1 Internal 

Cabling 

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. 

 

 

Figure 3 Suggested Internal Cabling

   

Cable losses are negligible for the short piece used within the chassis.  
Additional losses up to 0.5 dB may be present in the MCX and Reverse 
TNC connections. 

RG316 Cable

with MCX male

connector

and Reverse TNC

bulkhead

connector

Reverse TNC Connector

MCX female connector

N920

 

Summary of Contents for n920

Page 1: ...ng Manual n920 900 MHz Spread Spectrum OEM Transceiver Revision 0 10 April 16 2008 17 2135 32nd Ave N E Calgary Alberta T3K 4Z4 Phone 403 248 0028 Fax 403 248 2762 www microhardcorp com Microhard Syst...

Page 2: ...ONAL WARRANTY Indemnification The Purchaser shall indemnify Microhard Systems Inc and its respective directors officers employees successors and assigns including any subsidiaries related corporations...

Page 3: ...s fixed antennas require installation preventing end users from replacing them with non approved antennas Antennas not listed in the tables must be tested to comply with FCC Section 15 203 unique ante...

Page 4: ...ights ii n920 Regulatory Requirements iii CONTENTS IV 2 GENERAL 1 2 0 PRODUCT OVERVIEW 1 2 1 OUTPUT POWER LEVEL 2 3 INSTALLATION 3 3 0 OVERVIEW 3 3 1 ESTIMATING THE GAIN MARGIN 3 3 2 ANTENNAS AND CABL...

Page 5: ...dio spectrum1 this means that it can be used without access fees such as those incurred by cellular airtime a serial I O data port with handshaking and hardware flow control allowing the N920 to inter...

Page 6: ...ommended that the lowest power necessary is used using excessive power contributes to unnecessary RF pollution Ideally you should test the communications performance between units starting from a low...

Page 7: ...nowledge of the equipment being deployed The following four factors make up a system gain calculation 1 Transmitter power user selectable 2 Transmitter gain transmitting antenna gain minus cabling los...

Page 8: ...tem gain and path loss Referring to the same example suppose the path loss is 100 dB the gain margin would be 40 dB which is more than adequate for reliable communication Path loss is a very complicat...

Page 9: ...cedure for installing cabling and antennas for use with the N920 module 3 2 1 Internal Cabling The most common method for installing the module is to run a cable from the module s MCX connector to a r...

Page 10: ...most effective protection against lightning is to install two lightning surge arrestors one at the antenna the other one at the interface with the equipment The surge arrestor grounding system should...

Page 11: ...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 grou...

Page 12: ...the maximum power setting of 30dBm Example 2 What is the maximum power the N920 can be set to comply with FCC and IC given the following equipment given a Yagi Ant Gain 12dBd and cable and connector l...

Page 13: ...d 900MHz Yagi Directional Antenna Bluewave RPTNC Pigtail Patch Antennas MHS031440 8dBi 900 MHz Patch Antenna RPTNC Pigtail MHS031430 12 5dBi 900 MHz Patch Antenna RPTNC Pigtail Omni Directional MHS031...

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