User Manual

FCC ID: NS909P29

Users Manual

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FCCID_1120671

Operating Manual




L400
400–480 MHz Narrowband Modem
Revision 0.20, June 4, 2009




                                 Model: L400
        Microhard Systems Inc.
#17, 2135 – 32nd Ave N.E.
Calgary, Alberta T3K 4Z4
Phone: (403) 248-0028
Fax: (403) 248-2762
www.microhardcorp.com


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. Product returned to Microhard Systems Inc. for
warranty service will be shipped to Microhard Systems Inc. at Buyer’s expense and will be returned to Buyer at Microhard
Systems Inc.’s expense. In no event shall Microhard Systems Inc. be responsible under this warranty for any defect which is
caused by negligence, misuse or mistreatment of a product or for any unit which has been altered or modified in any way. The
warranty of replacement shall terminate with the warranty of the product.

Warranty Disclaims
Microhard Systems Inc. makes no warranties of any nature of kind, expressed or implied, with respect to the hardware, software,
and/or products and hereby disclaims any and all such warranties, including but not limited to warranty of non-infringement,
implied warranties of merchantability for a particular purpose, any interruption or loss of the hardware, software, and/or product,
any delay in providing the hardware, software, and/or product or correcting any defect in the hardware, software, and/or product,
or any other warranty. The Purchaser represents and warrants that Microhard Systems Inc. has not made any such warranties to
the Purchaser or its agents MICROHARD SYSTEMS INC. EXPRESS WARRANTY TO BUYER CONSTITUTES
MICROHARD SYSTEMS INC. SOLE LIABILITY AND THE BUYER’S SOLE REMEDIES. EXCEPT AS THUS
PROVIDED, MICROHARD SYSTEMS INC. DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PROMISE.

MICROHARD SYSTEMS INC. PRODUCTS ARE NOT DESIGNED OR INTENDED TO BE USED IN
ANY LIFE SUPPORT RELATED DEVICE OR SYSTEM RELATED FUNCTIONS NOR AS PART OF
ANY OTHER CRITICAL SYSTEM AND ARE GRANTED NO FUNCTIONAL WARRANTY.


Indemnification
The Purchaser shall indemnify Microhard Systems Inc. and its respective directors, officers, employees, successors
and assigns including any subsidiaries, related corporations, or affiliates, shall be released and discharged from any
and all manner of action, causes of action, liability, losses, damages, suits, dues, sums of money, expenses
(including legal fees), general damages, special damages, including without limitation, claims for personal injuries,
death or property damage related to the products sold hereunder, costs and demands of every and any kind and
nature whatsoever at law.

IN NO EVENT WILL MICROHARD SYSTEMS INC. BE LIABLE FOR ANY INDIRECT, SPECIAL,
CONSEQUENTIAL, INCIDENTAL, BUSINESS INTERRUPTION, CATASTROPHIC, PUNITIVE OR OTHER
DAMAGES WHICH MAY BE CLAIMED TO ARISE IN CONNECTION WITH THE HARDWARE,
REGARDLESS OF THE LEGAL THEORY BEHIND SUCH CLAIMS, WHETHER IN TORT, CONTRACT OR
UNDER ANY APPLICABLE STATUTORY OR REGULATORY LAWS, RULES, REGULATIONS,
EXECUTIVE OR ADMINISTRATIVE ORDERS OR DECLARATIONS OR OTHERWISE, EVEN IF
MICROHARD SYSTEMS INC. HAS BEEN ADVISED OR OTHERWISE HAS KNOWLEDGE OF THE
POSSIBILITY OF SUCH DAMAGES AND TAKES NO ACTION TO PREVENT OR MINIMIZE SUCH
DAMAGES. IN THE EVENT THAT REGARDLESS OF THE WARRANTY DISCLAIMERS AND HOLD
HARMLESS PROVISIONS INCLUDED ABOVE MICROHARD SYSTEMS INC. IS SOMEHOW HELD
LIABLE OR RESPONSIBLE FOR ANY DAMAGE OR INJURY, MICROHARD SYSTEMS INC.'S LIABILITY
FOR ANYDAMAGES SHALL NOT EXCEED THE PROFIT REALIZED BY MICROHARD SYSTEMS INC.
ON THE SALE OR PROVISION OF THE HARDWARE TO THE CUSTOMER.
Proprietary Rights
The Buyer hereby acknowledges that Microhard Systems Inc. has a proprietary interest and intellectual property rights in the
Hardware, Software and/or Products. The Purchaser shall not (i) remove any copyright, trade secret, trademark or other evidence
of Microhard Systems Inc.’s ownership or proprietary interest or confidentiality other proprietary notices contained on, or in, the
Hardware, Software or Products, (ii) reproduce or modify any Hardware, Software or Products or make any copies thereof, (iii)
reverse assemble, reverse engineer or decompile any Software or copy thereof in whole or in part, (iv) sell, transfer or otherwise
make available to others the Hardware, Software, or Products or documentation thereof or any copy thereof, except in accordance
with this Agreement.




ii                                                                                                          L400 Operating Manual


L400 Regulatory Requirements

PLEASE READ THIS SECTION CAREFULLY

      WARNING:
To satisfy FCC RF exposure requirements for mobile transmitting devices, a separation distance is based on
the above them ranging from 39 cm to 305 cm 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.



                                  Impedance                                  Minimum Separation
        Antenna                                    Antenna Gain (dBi)
                                    (ohms)                                      Distance (cm)
 Minimum Gain                         50                    0                         39
 Maximum Gain                         50                    18                       305



      WARNING:
EQUIPMENT LABELING
The FCC and IC numbers depend on the model of the radio module. Do NOT use the Marketing
Name of the product but the Model to distinguish the Certifications Numbers. This device has
been modularly approved. The manufacturer, product name, and FCC and Industry Canada
identifiers of this product must appear on the outside label of the end-user equipment.




SAMPLE LABEL REQUIREMENT for Model: L400:

 Contains:
 FCCID: NS909P29           IC : 3143A-09P29
 This device complies with Part 15 of the FCC Rules.
 Operation is subject to the following two conditions:
 (1) this device may not cause harmful interference,
 and (2) this device must accept any interference
 received including interference that may cause
 undesired operation.




L400 Operating Manual: Contents                                                                          iii


Contents
Warranty ....................................................................................................................................................................... ii
Warranty Diclaims ........................................................................................................................................................ ii
Indemnification............................................................................................................................................................. ii
Proprietary Rights ......................................................................................................................................................... ii
L400 Regulatory Requirements ................................................................................................................................... iii
CONTENTS .............................................................................................................................................................. IV
2.     GENERAL ........................................................................................................................................................... 1
     2.0       PRODUCT OVERVIEW ........................................................................................................................................................ 1
     2.1       OUTPUT POWER LEVEL ..................................................................................................................................................... 2
3.     INSTALLATION................................................................................................................................................. 4
     3.0       OVERVIEW ....................................................................................................................................................................... 4
     3.1       ESTIMATING THE GAIN MARGIN ....................................................................................................................................... 4
     3.2       ANTENNAS AND CABLING ................................................................................................................................................. 6
       3.2.1 ........................................................................................................................Internal Cabling
       ............................................................................................................................................................................... 6
       3.2.2 ............................................................Installing External Cables, Antennas and Lightning Arrestors
       ............................................................................................................................................................................... 7




iv                                                                                                                                                          L400 Operating Manual


                                                                                    2. General
                                          2.0 Product Overview
                                          The L400 is a high-performance embedded wireless data transceiver.
                                          Operating in the 400 - 480 MHz band, this narrowband module is capable
                                          of providing reliable wireless data transfer between almost any type of
                                          equipment which uses an asynchronous serial interface. The small-size and
                                          superior RF performance of this module make it ideal for many
                                          applications.

                                          While a pair of L400 modules can link two terminal devices (“point-to-
                                          point” operation); multiple modules can be used together to create a
                                          network of various topologies, including “point-to-multipoint” and
                                          “repeater” operation. Multiple independent networks can operate
                                          concurrently, so it is possible for unrelated communications to take place in
                                          the same or a nearby area without sacrificing privacy or reliability.

                                          1.1 Features
                                          Key features of the L400 include:
                                              „a serial I/O data port with handshaking and hardware flow
                                                 control, allowing the L400 to interface directly to any
                                                 equipment with an asynchronous serial interface.
                                              „ ease of installation and use – the L400 module uses a subset of
                                                 standard AT style commands, very similar to those used by
                                                 traditional telephone line modems.
                                              „ all units in a system are physically identical, and can be
                                                 configured as a master, repeater or slave using the AT
                                                 command set. No hardware modifications are required
                                              „ 32-bit of CRC error detection and auto re-transmit to provide
                                                 accuracy and reliability of data.




L400 Operating Manual: Chapter2 General                                                                               1


         „ TDMA (time division multiple access) support, allowing
            multi-slave access in point-to-point mode.
         „ roaming ability, allowing repeaters and slaves to re-
            synchronize with a new master if the synchronization pulse
            from the original master is lost.
    While the typical application for the L400 is to provide a short- to mid-
    range wireless communications link between DTEs, it can be adapted to
    almost any situation where an asynchronous serial interface is used and data
    intercommunication is required.


    2.1 Output Power Level
    The Output Power Level determines at what power the L400 transmits. The
    L400’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”.
    Ideally, you should test the communications performance between units
    starting from a low power level and working upward until the RSSI is
    sufficiently high and a reliable link is established. The conditions will vary
    widely between applications, the output power settings can be calculated
    based on following information.
    •   Transmitter antenna gain
    •   Cable loss
    •   Effective radiated power (ERP) requirement by FCC Regulations


        Power Setting = 36 – Antenna Gain – Cable Loss
    The power setting must be no more than the above calculation value. Any
    higher is a violation of FCC rules. See IMPORTANT warning below.
    Table 1 Output Power

            Power Setting      Approx. Output Power
               (dBm)                   (mW)
                  0                        1
                  20                      100
                  21                      125
                  22                      160
                  23                       200
                  24                       250
                  25                       320
                  26                       400
                  27                       500
                  28                       630
                  29                       800
                  30                      1000
                  33                      2000
                  35                      3162
                  37                      5000




2                                       L400 Operating Manual: Chapter 2 General


L400 Operating Manual: Chapter2 General   3


                                                  3. Installation
    3.0 Overview
    Qualified and experienced personnel must carry out the
    installation, removal or maintenance of all antenna
    components.
    The L400 complies with FCC part 15 at the modular level for operation in
    the license-free 400 to 480MHz depending on the country of operation there
    maybe some band restrictions. This chapter provides guidelines for
    installing and deploying equipment which incorporates the L400 module.

    3.1 Estimating the Gain Margin
    Successful communication between L400 modules is dependent on three
    main factors:
    •       System Gain
    •       Path Loss
    •       Interference
    System gain is a calculation in dB describing the performance to be
    expected between a transmitter-receiver pair. The number can be calculated
    based on knowledge 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 loss between
            the transmitting antenna and the L400 module)
    3.      Receiver gain (Receiving antenna gain minus cabling loss between the
            receiving antenna and the module)
    4.      Receiver sensitivity (Specified as -108dBm on the L400 module)
    In the following illustration, the transmitting antenna has a gain of 6 dB,
    and the receiving antenna has a gain of 3 dB. The cable loss between the
    module and the antenna is 2 dB on both the transmitting and receiving side.
                  Cable Loss = 2 dB                                                     Cable Loss = 2 dB


                                  Antenna Gain = 6 dB             Antenna Gain = 3 dB


         Transmitter                                                                                   Receiver

          30 dBm                                                                                     Sensitivity =
        Output Power                                                                                  -105 dBm




4                                                       L400 Operating Manual: Chapter 3 Installation


                                    Figure 1 Gain Calculation
                                    The power level has been set to 30dBm (1W) on the transmitter, and the
                                    receiver sensitivity for the L400 is -108dBm.
                                    System gain would be calculated to be:
                                    30 - 2 + 6 + 3 - 2 + 108 = 143 dB.

                                         Base Height (m)



                                                           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).
                                    It is recommended to design for a gain margin of at least 20 dB to ensure
                                    reliable communication. Gain margin is the difference between system 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 complicated calculation which mainly depends on the
                                    terrain profile, and the height of the antennas off the ground.
                                    The following table provides path loss numbers for varying antenna heights
                                    and antenna separation: These numbers are real averages taken from rural
                                    environments. They do not apply to urban, non-line-of-sight environments.
                                    Table 2 Path Loss

                                      Distance              Base Height   Mobile Height        Path Loss
                                       (km)                     (m)           (m)                (dB)
                                          5                         15         2.5               116.5
                                          5                         30         2.5               110.9
                                          8                         15         2.5               124.1
                                          8                         15          5                117.7
                                          8                         15         10                 105
                                         16                         15         2.5               135.3
                                         16                         15          5                128.9
                                         16                         15         10                116.2
                                         16                         30         10                109.6
                                         16                         30          5                122.4
                                         16                         30         2.5               128.8




MHX-920 Operating Manual:Glossary                                                                           5


                               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
     WARNING:                  This section describes the recommended procedure for installing cabling
Qualified and experienced      and antennas for use with the L400 module.
personnel must carry out the
installation, removal or       3.2.1   Internal Cabling
maintenance of all antenna     The most common method for installing the module is to run a cable from
components.                    the module’s MCX connector to a reverse TNC, N-female, or SMA
                               bulkhead connector on the chassis of the equipment as shown in Figure 3.
                               This cable can be purchased from Microhard Systems.
                                              External Antenna Connector




                                                              RG316 Cable
                                                             with MCX male
                                                                connector
                                                            and Reverse TNC
                                                                bulkhead
                                                                connector
                                                     MCX female connector
                                              L400




                               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.




6                                                                  MHX-920 Operating Manual: Glossary


                                    3.2.2     Installing External Cables, Antennas and Lightning
                                              Arrestors
                                    Qualified and experienced personnel must carry out the installation,
     WARNING:                       removal or maintenance of all antenna components. Never work on an
Direct human contact with the       antenna system when there is lightning in the area.
antenna is potentially unhealthy
when the L400 is generating RF      Direct human contact with the antenna is potentially unhealthy when the
energy. Always ensure that the      L400 is generating RF energy. Always ensure that the L400 equipment is
L400 equipment is powered down      powered down during installation. At all times a distance of shown below
during installation.                should be maintained between the antenna and any person when the device
                                    is in operation.


                                                       Impedance                               Minimum
                                                                           Antenna
     WARNING:                          Antenna           (ohms)                                Separation
Never work on an antenna                                                  Gain (dBi)
                                                                                              Distance (cm)
system when there is lightning in
                                     Min Gain                50                0                   39
the area.
                                     Max Gain                50                18                  305



                                    Surge Arrestors
                                    The 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 be fully
                                    interconnected with the transmission tower and power grounding systems to
                                    form a single, fully integrated ground circuit. Typically, both ports on surge
                                    arrestors are N-female.
                                    External Filter
                                    Although the L400 is capable of filtering out RF noise in most
                                    environments, there are circumstances that require external filtering.
                                    Paging towers and cellular base stations in close proximity to the L400
                                    antenna can desensitize the receiver. Microhard Systems’ external cavity
                                    filter eliminates this problem. The filter has two N-female ports and should
                                    be connected in line at the interface to the RF equipment.
                                    Cabling
                                    The following coax cables are recommended:
                                    Table 3 Cable Loss

                                        Cable         Loss (dB/100ft)
                                      LMR 195               10.7
                                      LMR 400                3.9
                                      LMR 600                2.5




MHX-920 Operating Manual:Glossary                                                                               7


                                    Factors to take into consideration when choosing a cable are:
     WARNING:
The L400 can only be used with      •   price;
any antennas listed in Appendix     •   bend radius limitations (the lower performance cables generally can
A and this the antenna                  bend more sharply)
separations shown in Appendix
A.                                  •   performance requirements; and,
                                    •   distance between the equipment and the antenna.
     WARNING:
Be careful with dBi vs dBd gains    When installing the cable, always begin fastening at the top near the
on antenna specifications.          antenna connector/surge arrestor. The cable must be supported at the top
Antenna manufactures may not        with a hose clamp or wrap lock, and at 5 ft intervals down the length of the
clearly indicate the gain on the    tower. Over-tightening the fasteners will dent the cable and reduce
antenna if it is dBd or dBi. Note   performance. If properly grounded surge arrestors are not installed at both
1dBd            =        2.15dBi.   the top and the bottom of the cable, then the cable should be grounded to
                                    the tower at these locations using a cable grounding kit. If the tower is non-
                                    conductive, then a separate conductor, physically separate from the cable,
                                    should be run down 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.
                                    In applications where there are multiple units that you must communicate
                                    with or units, which are in motion, you may select an Omni-directional
                                    antenna with appropriate gain.
                                    See appendix A for a list of approved antennas types that can be used
                                    with the L400 radio modem. If you require another type of antenna
                                    please contact Microhard Systems Inc.
                                    Microhard Systems Inc. can provide you with approved antennas to ensure
                                    FCC and Industry Canada compliance.
                                    ERP is calculated as follows:
                                    ERP = Tx Power(dBm) - Cable/Connector Loss(dB) + Ant Gain(dBi)


                                    Antenna Gains must be in dBi when calculating the 36dBm ERP limit.
                                    1dBd = 2.15dBi


                                    Use the guidelines in the previous section for calculating cable and
                                    connector losses. If cabling and connector losses are 2 dB, then the
                                    maximum allowable gain of the antenna will be 8 dB.




8                                                                         MHX-920 Operating Manual: Glossary


                                 A. Antenna / Separations


                                  Impedance                                     Minimum Separation
          Antenna                                   Antenna Gain (dBi)
                                    (ohms)                                         Distance (cm)
 Minimum Gain                         50                       0                         39
 Maximum Gain                         50                       18                       305

  RF EXPOSURE DISTANCE LIMITS

                   P ⋅G         EIRP
            r=             =
                  4 ⋅π ⋅ S     4 ⋅π ⋅ S

  Sample calculation:

  S = 406.1/1500 mW/cm2

  EIRP = 42 dBm = 1042/10 mW = 15849 mW (Worst Case for Quarter Wave antenna)

                                    EIRP                 15849
  (Minimum Safe Distance, r) =              =                          ≈ 68cm
                                   4 ⋅π ⋅ S     4 ⋅ π ⋅ (406.1 / 1500)




        WARNING:
  Changes or modifications not expressly approved by Microhard Systems Inc. could void the user’s
  authority to operate the equipment. Please Contact Microhard Systems Inc. if you need more information.




        WARNING:
  To satisfy FCC RF exposure requirements for mobile transmitting devices, a separation distance is based
  on the above them ranging from 39 cm to 305 cm 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.




MHX-920 Operating Manual:Glossary                                                                           9



Document Created: 2009-06-04 12:13:11
Document Modified: 2009-06-04 12:13:11

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