Microwave Data Systems MDS 9810 Operating instructions

Installation and Operation Guide
Installation & Operation Guide
MDS 05-3301A01, Rev. C
JULY 2004
900 MHz Spread Spectrum
DataTransceivers
Microwave Data Systems Inc.
MDS 9810

QUICK START GUIDE
Below are the basic steps for installing the transceiver. Detailed instructions are given in “INSTALLA-
TION” on Page 14 of this guide.
1. Install and connect the antenna system to the radio
• Use good quality, low-loss coaxial cable.Keep the feedline as short as possible.
• Preset directional antennas in the direction of desired transmission.
2. Connect the data equipment to the radio’s INTERFACE connector
• Connection to the radio must be made with a DB-25 Male connector.Connections for typical sys-
tems are shown below.
• Connect only the required pins.Do not use a straight-through RS-232 cable with all pins wired.
• Verify the data equipment is configured as DTE.(By default, the radio is configured as DCE.)
3. Apply DC power to the radio
• Observe proper polarity.The red wire is the positive lead; the black is negative.
4. Set the radio’s basic configuration with a Hand-HeldTerminal (HHT)
• Set the baud rate/data interface parameters as follows. Use the BAUD xxxxx abc command,
where xxxxx equals the data speed and abc equals the communication parameters as follows:
a = Data bits (7 or 8)
b = Parity (N for None, O for Odd, E for Even
c = Stop bits (1 or 2)
(Example: BAUD 9600 8N1 ) NOTE: 7N1, 8E2 and 8O2 are invalid data parameters.
5. Verify proper operation by observing the LED display
• Refer to Table 4 on Page 26 for a description of the status LEDs.
• Refine directional antenna headings for best received signal strength using the RSSI command.
• If difficulties are encountered, please refer to Table 14 on Page 56 for troubleshooting help.
DB-25 DB-25
2
3
2
3
4
5
20
6DSR DSR
6
TXD
RXD
GND
RTS
CTS
TXD
RXD
GND
4
CTS
5
RTS
DB-9 DB-25
DB-9 to DB-25 ExampleDB-25 to DB-25 Example
11
4
5
2
3
3
2
5
20
7
RXD
TXD
DCD
GND
DSR
RTS
RXD
TXD
DCD
GND
As required for application
5
18
7
6
CTS
DSR
RTS
CTS8
6
4
5
77
GND GND
8 8
DCD DCD
As required for application
RTU
(DTE)
TRANSCEIVER
(DCE)
RTU
(DTE)
TRANSCEIVER
(DCE)

MDS 05-3301A01, Rev. C MDS 9810 Installation and Operation Guide i
TABLE OF CONTENTS
1.0 ABOUT THIS MANUAL.........................................................................................................1
2.0 PRODUCT DESCRIPTION...................................................................................................1
Transceiver Features........................................................................................................................2
Model Configuration Codes .............................................................................................................2
2.1 Spread Spectrum Radios—How Are They Different? ....................................................................3
2.2 Typical Applications .......................................................................................................................3
Multiple Address Systems (MAS) ....................................................................................................3
Simplex “Peer-to-Peer”.....................................................................................................................4
Peer-to-Peer with Repeater Assistance...........................................................................................4
Point-to-Point System.......................................................................................................................5
Tail-End Link (“MAS Extension”)......................................................................................................5
Repeater System—Traditional.........................................................................................................6
“Single-Radio”Repeater—Alternative Method.................................................................................6
2.3 Accessories ...................................................................................................................................7
3.0 INSTALLATION PLANNING..................................................................................................7
3.1 General Requirements ..................................................................................................................7
3.2 Site Selection ................................................................................................................................8
Terrain and Signal Strength .............................................................................................................9
Conducting a Site Survey ................................................................................................................9
3.3 A Word About Radio Interference ................................................................................................10
3.4 Antenna & Feedline Selection .....................................................................................................11
Antennas........................................................................................................................................11
Feedlines .......................................................................................................................................12
3.5 How Much Output Power Can be Used? .....................................................................................13
Transmitter Power vs. Antenna System Gain.................................................................................13
4.0 INSTALLATION...................................................................................................................14
4.1 Transceiver Installation ................................................................................................................15
4.2 Peer-to-Peer Systems .................................................................................................................19
Simplex Peer-to-Peer.....................................................................................................................19
Peer-to-Peer with Repeater Assistance.........................................................................................20
4.3 Tail-End Links ..............................................................................................................................21
Interface Wiring..............................................................................................................................21
Programming .................................................................................................................................22
4.4 Repeaters—Traditional Method ...................................................................................................22
Antennas........................................................................................................................................23
System Addresses.........................................................................................................................23
Interface Wiring..............................................................................................................................23
Diagnostic Limitations....................................................................................................................23

ii MDS 9810 Installation and Operation Guide MDS 05-3301A01, Rev. C
4.5 “Single-Radio”Repeater—Alternative Method ............................................................................24
Interface Wiring..............................................................................................................................24
Software Programming (TDD Command)......................................................................................24
Limitations of Single-Radio Repeaters...........................................................................................25
4.6 Using the Radio’s Sleep Mode ....................................................................................................25
Sleep Mode Example.....................................................................................................................25
5.0 OPERATION.......................................................................................................................26
5.1 Initial Start-up ..............................................................................................................................26
5.2 Performance Optimization ...........................................................................................................26
Antenna Aiming..............................................................................................................................27
Antenna SWR Check.....................................................................................................................27
Data Buffer Setting.........................................................................................................................27
Hoptime Setting .............................................................................................................................27
Baud Rate Setting..........................................................................................................................28
Radio Interference Checks.............................................................................................................28
6.0 PROGRAMMING................................................................................................................28
6.1 Hand-Held Terminal Connection & Start-up ................................................................................28
6.2 Hand-Held Terminal Setup ..........................................................................................................29
6.3 Keyboard Commands ..................................................................................................................30
Entering Commands......................................................................................................................30
Error Messages..............................................................................................................................31
6.4 Detailed Command Descriptions .................................................................................................35
ADDR [1...65000]...........................................................................................................................36
AMASK [0000 0000–FFFF FFFF]..................................................................................................36
ASENSE [HI/LO]............................................................................................................................36
BAUD [xxxxx abc] ..........................................................................................................................36
BUFF [ON, OFF]............................................................................................................................37
CTS [0–255]...................................................................................................................................37
CTSHOLD [0-6000]........................................................................................................................38
DEVICE [DCE, CTS KEY].............................................................................................................38
DLINK [xxxxx] ................................................................................................................................39
DMGAP [xx]...................................................................................................................................39
DTYPE [NODE/ROOT/GATE/PEER] .............................................................................................39
HOPTIME [XSHORT, 16, 20, 25, 32, SHORT, NORMAL, LONG] .................................................40
INIT................................................................................................................................................41
MODE [M, R, R-M].........................................................................................................................41
OWM [xxxxx]..................................................................................................................................42
OWN [xxxxx] ..................................................................................................................................42
PWR [xx–30]..................................................................................................................................42
RSSI...............................................................................................................................................42
RTU [ON/OFF/0-80].......................................................................................................................43
RX [xxxx]........................................................................................................................................43
RXTOT [NONE, 0–1440]................................................................................................................43
SEND [n, -n, +n].............................................................................................................................43
SETUP...........................................................................................................................................44
SHOW [PORT, DC, PWR]..............................................................................................................45
SIMPLEX [ON, OFF]......................................................................................................................45

MDS 05-3301A01, Rev. C MDS 9810 Installation and Operation Guide iii
SKIP [NONE, 1...8] ........................................................................................................................46
SKIPSYNC [ON/OFF]....................................................................................................................46
SNR ...............................................................................................................................................46
SREV.............................................................................................................................................47
STAT...............................................................................................................................................47
TDD [ON/OFF]...............................................................................................................................47
TEMP.............................................................................................................................................48
TX [xxxx]........................................................................................................................................48
UNIT [10000–65000]......................................................................................................................48
ZONE DATA ...................................................................................................................................49
ZONE CLEAR................................................................................................................................50
7.0 TROUBLESHOOTING........................................................................................................50
7.1 LED Indicators .............................................................................................................................50
7.2 Alarm Codes ................................................................................................................................51
Checking for Alarms—STAT command..........................................................................................51
Major Alarms vs. Minor Alarms......................................................................................................51
Alarm Code Definitions..................................................................................................................52
7.3 Performing Network-Wide Remote Diagnostics ..........................................................................53
DLINK [xxxxx] ................................................................................................................................55
DTYPE [NODE/ROOT/GATE/PEER] .............................................................................................55
7.4 Troubleshooting Chart .................................................................................................................56
8.0 TECHNICAL REFERENCE.................................................................................................56
8.1 Technical Specifications ..............................................................................................................56
8.2 RSSI Checks with aVoltmeter .....................................................................................................58
8.3 Data Interface Connections (DB-25) ...........................................................................................58
8.4 Bench Testing Setup ....................................................................................................................61
8.5 Using Radio Configuration Software ...........................................................................................61
Connecting a PC............................................................................................................................62
Upgrading the Radio’s Software ....................................................................................................62
8.6 dBm-Watts-Volts Conversion Chart .............................................................................................63
9.0 GLOSSARY OF TERMS..................................................................................................... 63
Copyright Notice
This Installation and Operation Guide and all software described herein are protected by copy-
right: 2004 Microwave Data Systems
Inc. All rights reserved.
Microwave Data Systems reserves its right to correct any errors and omissions in this document.
Operational Safety Notice
The radio equipment described in this guide emits radio frequency energy. Although the power
level is low, the concentrated energy from a directional antenna may pose a health hazard. All
antennas used with this transmitter, whether indoor or outdoor mounted, must be installed to pro-
vide a separation distance of at least
23 cm from all persons, and must not be co-located or oper-
ating in conjunction with any other antenna or transmitter. In mobile applications (vehicle
RF
Exposure

iv MDS 9810 Installation and Operation Guide MDS 05-3301A01, Rev. C
mounted) the above separation distance must be maintained at all times. More information on RF
exposure is available on the Internet at
www.fcc.gov/oet/info/documents/bulletins . This manual
is intended to guide a professional installer to install, operate and perform basic system mainte-
nance on the described radio.
CSA/ US Notice
This product is available for use in Class I, Division 2, Groups A, B, C & D Hazardous Locations. Such
locations are defined in Article 500 of the National Fire Protection Association publication NFPA 70, oth-
erwise known as the National Electrical Code.
The product has been recognized for use in hazardous locations by the Canadian Standards Association
(CSA), which also issues the US mark of approval (CSA/
US ). The CSA Certification is in accordance with
CSA STD C22.2 No. 213-M1987. The product has been evaluated in accordance with the following stan-
dards:
• CSA Std C22.2 No. 142-M1987 - Process Control Equipment
• CSA Std C22.2 No. 213-M1987 - Non-Incendive Electrical Equipment for Use in Class I, Division 2
Hazardous Locations
• ANSI/UL Std No. 508 - Industrial Control Equipment
• UL Std No. 1604 - Electrical Equipment for Use in Class I and II, Division 2; Class III Hazardous (Clas-
sified) Locations
ISO 9001 Registration
Microwave Data Systems' adherence to this internationally accepted quality system standard pro-
vides one of the strongest assurances of product and service quality available.
MDS Quality Policy Statement
We, the employees of Microwave Data Systems, are committed to achieving total customer satis-
faction in everything we do.
Total Customer Satisfaction in:
• Conception, design, manufacture and marketing of our products.
• Services and support we provide to our internal and external customers.
Total Customer Satisfaction Achieved Through:
• Processes that are well documented and minimize variations.
• Partnering with suppliers who are committed to providing quality and service.
• Measuring our performance against customer expectations and industry leaders.
• Commitment to continuous improvement and employee involvement.

MDS 05-3301A01, Rev. C MDS 9810 Installation and Operation Guide v
FCC Notice, U.S.A.
The transceiver 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.
This device is specifically designed to be used under Section 15.247 of the FCC Rules and Regu-
lations. Any unauthorized modification or changes to this device without the express approval of
Microwave Data Systems may void the user’s authority to operate this device.
Furthermore, this device is indented to be used only when installed in accordance with the instruc-
tions outlined in this manual. Failure to comply with these instructions may also void the user’s
authority to operate this device.
Manual Revisions/Updates
While every reasonable effort has been made to ensure the accuracy of this manual, product
improvements may result in minor differences between the manual and the product shipped to you.
If you have additional questions or need an exacts specification for a product, please contact our
Customer Service Team using the information at the back of this guide. In addition, manual
updates can often be found on the MDS Web site at www.microwavedata.com.

vi MDS 9810 Installation and Operation Guide MDS 05-3301A01, Rev. C

MDS 05-3301A01, Rev. C MDS 9810 Installation and Operation Guide 1
1.0 ABOUTTHIS MANUAL
This guide presents installation and operating instructions for the
MDS 9810 transceiver. Following installation, we suggest keeping this
guide near the equipment for future reference.
NOTE: Earlier versions of this manual also covered the MDS 24810
(2.4 GHz) transceiver, which has been discontinued by MDS.
An electronic version of the earlier manual is available for
download at www.microwavedata.com.
2.0 PRODUCT DESCRIPTION
The transceiver, shown in Figure 1, is a spread spectrum radio designed
for license-free operation in the 900 MHz frequency band. Employing
microprocessor control and Digital Signal Processing (DSP) tech-
nology, the unit is highly reliable for long-distance communications,
even in the presence of weak signals or interference.
DSPtechnology alsomakes it possible to obtaininformation aboutradio
operation and troubleshoot problems, without going to the remote radio
site.Using theappropriate softwareat the master station, diagnostic data
can be obtained on any DSP radio in the system, even while payload
data is being transmitted. (See “Performing Network-Wide Remote
Diagnostics” on Page 53.)
The transceiver is housed in a compact and rugged die-cast aluminum
case that need only be protected from direct exposure to the weather. It
contains a single printed circuit board with all necessary components for
radio operation. No jumper settings or adjustments are required to con-
figure the radio for operation.
Invisible place holder
Figure 1. MDS 9810 Transceiver
EXTERNAL
INTERFACE
CONNECTOR
(DB-25)
DIAGNOSTICS
CONNECTOR (RJ-11)
13.8 VDC POWER
CONNECTOR ANTENNA CONNECTOR
(TYPE “N”)
SERIAL NUMBER
LABEL
LED INDICATORS (4)

2 MDS 9810 Installation and Operation Guide MDS 05-3301A01, Rev. C
Transceiver Features
Listed below are several key features of the transceiver. These are
designed to ease the installation and configuration of the radio, while
retaining the ability to make changes in the future.
• 1,019 frequencies over 902–928 MHz, subdivided into eight
frequency zones
• Configurable operating zones to omit frequencies with constant
interference
• 65,000 available network addresses
• Network-wideconfiguration from themaster station;eliminates
most trips to remote sites
• Data transparency–ensures compatibility with virtually all
asynchronous SCADA system RTUs
• Peak-hold RSSI, averaged over eight hop cycles
• Operation at up to 19200 bps continuous data flow;
38400 bps non-continuous
• Same hardware for all supported data rates:
1200, 2400, 4800, 9600, 19200, 38400 bps asynchronous
• Same hardware for master or remote configuration
• Data latency typically less than 10 ms
• Supports EIA-232 (formerly called RS-232) user interface
• Low current consumption–30 mA or less average draw in
“sleep” mode.
Model Configuration Codes
Theradio model number is printed on the endof the radio enclosure, and
provides key information about how the radio was configured when it
left the factory. See Figure 2 for an explanation of the model number
characters.
Invisible place holder
Figure 2. Transceiver Model Configuration Codes
98
PACKAGE
1= Transceiver only
OPERATION
X= Remote/Master
POWER SETTING
1= 10.5 - 30 Vdc*
DIAGNOSTICS
0= None
1= Non-Intrusive
N= N/A
SAFETY APPROVAL
N= N/A
MOUNTING BRACKETS
A= Standard
B= None
0XN
AGENCY APPROVAL
F= FCC/IC
U= FM/UL/CSA
* Units shipped prior to Revision “U”(November 1999) may be configured for 25 Vdc maximum DC input.
THIS INFORMATION IS
SUBJECT TO CHANGE.
DO NOT USE FOR
PRODUCT ORDERING.

MDS 05-3301A01, Rev. C MDS 9810 Installation and Operation Guide 3
Invisible place holder
2.1 Spread Spectrum Radios—How Are They
Different?
The main difference between a traditional (licensed) radio system and
the MDS 9810 transceiver is that these units “hop” from channel to
channel many times per second using a specific hop pattern applied to
all radios in the network. A distinct hopping pattern is provided for each
of the 65,000 available network addresses, thereby minimizing the
chance of interference with other spread spectrum systems. In the USA,
and certain other countries, no license is required to install and operate
this type of radio system.
2.2 Typical Applications
Multiple Address Systems (MAS)
This is the most common application of the transceiver. It consists of a
central control station (master) and two or more associated remote units,
as shown in Figure 3. An MAS network provides communications
between a central host computer and remote terminal units (RTUs) or
other data collection devices. The operation of the radio system is trans-
parent to the computer equipment. When used in this application, the
transceiver provides an excellent alternative to traditional (licensed)
MAS radio systems.
Invisible place holder
Figure 3. Typical MAS Network
RTU
RTU
RTU
RTU
RTU
MASTER RADIO
(MDS 9820 Shown)
REMOTE RADIO
REMOTE RADIO
REMOTE RADIO
REMOTE RADIO
REMOTE RADIO
HOST SYSTEM

4 MDS 9810 Installation and Operation Guide MDS 05-3301A01, Rev. C
Simplex “Peer-to-Peer”
Peer-to-peer communication is possible using the transceiver’s simplex
mode. With this arrangement (Figure 4), two or more remote units can
share information by direct communication with each other in addition
to communicating with a central master radio. This is possible because
the transmit and receive frequencies for each hop channel are the same
at each radio when simplex mode is enabled. If adequate transmission
paths exist, each radio can communicate with all other units in the net-
work. Additional details for peer-to-peer systems are provided in
Section 4.2 (Page 19).
Invisible place holder
Figure 4. Typical simplex “Peer-to-Peer”Network
Peer-to-Peer with Repeater Assistance
Peer-to-peer communication is also possible using this alternate
arrangement (see Figure 5). It overcomes the range limitations of a sim-
plex peer-to-peer system by using a repeater to re-transmit the signals of
all stations in the network. The repeater consists of two radios—one pro-
grammed as a remote using master frequencies (
MODE R-M command),
and the other programmed as a conventional master. Additional details
for peer-to-peer systems are given in Section 4.2 (Page 19).
RTU RTU
PEER-TO-PEER PEER-TO-PEER
RTU
RTU
REMOTE RADIO
MASTER RADIO
HOST SYSTEM
PEER-TO-PEER
REMOTE RADIO REMOTE RADIO
REMOTE RADIO

MDS 05-3301A01, Rev. C MDS 9810 Installation and Operation Guide 5
Invisible place holder
Figure 5. Typical Peer-to-Peer Network with Repeater Assistance
Point-to-Point System
A point-to-point configuration (Figure 6) is a simple arrangement con-
sisting of just two radios—a master and a remote. This provides a sim-
plexorhalf-duplex communications linkforthe transfer ofdatabetween
two locations.
Invisible place holder
Figure 6. Typical Point-to-Point Link
Tail-End Link (“MAS Extension”)
A tail-end link can be used to extend the range of a traditional (licensed)
MAS system. This might be required if an outlying site is blocked from
the MAS master station by a natural or man-made obstruction. In this
arrangement, an MDS 9810 radio links the outlying remote site into the
rest of a licensed MAS system by sending data from that site to an asso-
ciated MDS 9810 installed at one of the licensed remote sites. (See
Figure 7).
As the data from the outlying site is received at the licensed remote site,
it is transferred to the licensed radio (via a local cable connection) and
is then transmitted to the MAS master station in the usual manner. Addi-
tional details for tail-end links are given in Section 4.3 (Page 21).
RTU
REMOTE
HOST COMPUTER
RTU
RTU
REPEATER STATION
Pin 3 Pin 2
* Special operating mode.
See Programming section of manual.
REMOTE
REMOTE
REMOTE
REMOTE-MASTER*
MASTER
REMOTE RADIO
RTU
MASTER RADIO
HOST
SYSTEM

6 MDS 9810 Installation and Operation Guide MDS 05-3301A01, Rev. C
Invisible place holder
Figure 7. Typical Tail-End Link Arrangement
Repeater System —Traditional
Althoughthe range between MDS 9810 radios is typically10 to15miles
over average terrain, it is possible to extend the range considerably by
connecting two units together at one site in a “back-to-back” fashion to
form a repeater, as shown in Figure 8. Additional details for repeater
systems are given in Section 4.4 (Page 22).
Invisible place holder
Figure 8. Typical Repeater System Configuration
“Single-Radio”Repeater —Alternative Method
A repeater may also be established using a single MDS x810 Trans-
ceiver. This type of repeater cannot operate in full-duplex mode as with
the traditional repeater described above. However, if a loss in transmis-
sion speed and efficiency can be tolerated, it may be a viable solution in
some systems.
POINT
-T
O-POINT
SPREAD SPECTRUM
LINK
REMOTE
RADIO
MASTER
STATION
MAS SYSTEM (LICENSED OR UNLICENSED) MDS 9810/9820 LINK TO AN OUTLYING SITE
REPEATER
RTU
REMOTE
RADIO
Null-Modem
Cable
RTU
RTU
MDS 9810 / 9820
MASTER RADIO
MDS 9810 / 9820
REMOTE RADIO
REMOTE
RADIO
RTU
RTU
REPEATER LINK
Null-Modem Cable
RTU
MASTER
RADIO
REMOTE RADIO
REMOTE RADIO
REMOTE RADIO
REMOTE RADIO
MASTER
RADIO
HOST COMPUTER
POINT-TO-POINT LINK

MDS 05-3301A01, Rev. C MDS 9810 Installation and Operation Guide 7
A single-radio repeater works similar to the system shown in Figure 8,
but consists of just one transceiver at the repeater site. It works by buff-
ering (storing) incoming messages and retransmitting them a short time
later. Accordingly, there will be a delay in transmissions through this
type of repeater. Additional details for Single-Radio repeater s are given
in Section 4.5 (Page 24).
2.3 Accessories
The transceiver can be used with one or more of the accessories listed in
Table 1. Contact the factory for ordering details.
3.0 INSTALLATION PLANNING
The installation of the radio is not difficult, but it does require some
planning to ensure station reliability and efficiency. This section pro-
vides tips for selecting an appropriate site, choosing an antenna system,
and reducing the chance of harmful interference.
3.1 General Requirements
There are three main requirements for installing the radio—adequate
and stable primary power, a good antenna system, and the correct inter-
face between the transceiver and the data device.
Table 1. Accessories
Accessory Description MDS P/N
Power Supply
Kit For powering the transceiver from an AC source. 01-3682A01
Hand-Held
Terminal Kit
(HHT)
Terminal that plugs into the radio’s RJ-11
DIAG(NOSTICS) connector. Allows radio
programming, diagnostics & control. Includes
carrying case, cable set and manual.
02-1501A01
RTU Simulator Test unit that simulates data from a remote
terminal unit. Comes with polling software that
runs on a PC. Useful for testing radio operation.
03-2512A01
Radio
Configuration
Software
Windows-based software that allows radio
programming and control using a PC. Includes
on-line instructions. (See Section 8.5 (Page 61)
for PC connection details.)
03-3156A01
Paging Filter Antenna system filter used to reduce RF
interference from paging transmitters operating
in the 905-915 MHz band.
20-2822A01
Paging Filter Antenna system filter used to reduce RF
interference from paging transmitters operating
in the 902-927 MHz band.
20-22822A02
EIA-232 to
EIA-422
Converter
External adapter that converts the radio’s DATA
INTERFACE connector to EIA-422 compatible
signaling. May be required for long cable runs
(over 50 feet/15 meters).
03-2358A01

8 MDS 9810 Installation and Operation Guide MDS 05-3301A01, Rev. C
Figure 9 shows a typical remote station arrangement. At a remote sta-
tion,adirectional antenna isnormallyused,and aRemoteTerminalUnit
(RTU) or other telemetry equipment replaces the host computer nor-
mally used in a master station.
Invisible place holder
Figure 9. Typical Remote Station Arrangement
3.2 Site Selection
For a successful installation, careful thought must be given to selecting
proper sites for the master and remote stations. Suitable sites should pro-
vide:
• Protection from direct weather exposure
• A source of adequate and stable primary power
• Suitable entrances for antenna, interface or other required
cabling
• Antenna location that provides an unobstructed transmission
path in the direction of the associated station(s)
Theserequirements can be quickly determinedin mostcases. A possible
exception is the last item—verifying that an unobstructed transmission
path exists. Radio signals travel primarily by line-of-sight, and obstruc-
tions between the sending and receiving stations will affect system per-
formance. If you are not familiar with the effects of terrain and other
obstructions on radio transmission, the discussion below will provide
helpful background.
13.8 VDC
POWER
CABLE
13.8 VDC
POWER
SUPPLY
REMOTE TERMINAL
UNIT ANTENNA SYSTEM
(Directional Type
Normally Used)
LOW-LOSS FEEDLINE
REMOTE RADIO

MDS 05-3301A01, Rev. C MDS 9810 Installation and Operation Guide 9
Terrain and Signal Strength
While the 900 MHz band offers many advantages over VHF and lower
UHF frequencies for data transmission, they are also more prone to
signal attenuation from obstructions such as terrain, foliage or buildings
in the transmission path.
A line-of-sight transmission path between the master station and its
associated remote site(s)is highly desirable and provides the most reli-
able communications link. A line-of-sight path can often be achieved by
mounting the station antenna on a tower or other elevated structure that
raises it to a level sufficient to clear surrounding terrain and other
obstructions.
The importance of a clear transmission path relates closely to the dis-
tanceto becovered by the system. If the systemis tocover onlya limited
geographic area, say up to 3 miles (4.8 km), then some obstructions in
the transmission path can usually be tolerated with minimal impact. For
longer range systems, any substantial obstruction in the transmission
path could compromise the performance of the system, or block trans-
mission entirely.
Much depends on the minimum signal strength that can be tolerated in
a given system. Although the exact figure will differ from one system to
another, a Received Signal Strength Indication (RSSI) of –90 dBm or
stronger will provide acceptable performance in many systems. While
the equipment will work at lower signal strengths, this provides a “fade
margin” to account for variations in signal strength which may occur
from time-to-time. RSSI can be measured with a Hand-Held Terminal
connected to the remote radio’s DIAG(NOSTICS) connector. (See Section
6.0,beginning on Page 28.)
Conducting a Site Survey
If you are in doubt about the suitability of the radio sites in your system,
it is best to evaluate them before a permanent installation is begun. This
can be done with an on-the-air test (preferred method); or indirectly,
using path-study software.
An on-the-air test is preferred because it allows you to see firsthand the
factors involved at an installation site and to directly observe the quality
of system operation. Even if a computer path study was conducted ear-
lier, this test should be done to verify the predicted results.
The test can be performed by first installing a radio and antenna at the
proposed master station site and then visiting each remote site with a
transceiver and a hand-held antenna. (An RTU simulator—MDS Part
No. 03-2512A01—can be connected to each radio in the network to sim-
ulate data during this test.)

10 MDS 9810 Installation and Operation Guide MDS 05-3301A01, Rev. C
With the hand-held antenna positioned near the proposed mounting
spot, a technician can check for synchronization with the master station
(shown by a lit SYNC lamp on the front panel) and measure the reported
RSSI value. If adequate signal strength cannot be obtained, it may be
necessary to mount the station antennas higher, use higher gain
antennas, or select a different site. To prepare the equipment for an
on-the-air test, follow the general installation procedures given in this
guide and become familiar with the operating instructions given in Sec-
tion 5.0, beginning on Page 26.
If time is short, and a site survey is impractical, a computer path study
is a good alternative. Factors such as terrain, distance, transmitter
power, receiver sensitivity, and other conditions are taken into account
to predict the performance of a proposed system. Contact MDS for more
information on path study services.
3.3 A Word About Radio Interference
The transceiver shares frequency spectrums with other services and
other Part 15 (unlicensed) devices in the USA. As such, near 100% error
free communications may not be achieved in a given location, and some
level of interference should be expected. However, the radio’s flexible
design and hopping techniques should allow adequate performance as
long as care is taken in choosing station location, configuration of radio
parameters and software/protocol techniques.
In general, keep the following points in mind when setting up your com-
munications network:
1. Systems installed in rural areas are least likely to encounter
interference; those in suburban and urban environments are more
likely to be affected by other devices operating in the license-free
frequency band and by adjacent licensed services.
2. If possible, use a directional antenna at remote sites.Although these
antennas may be more costly than omnidirectional types, they con-
fine the transmission and reception pattern to a comparatively nar-
row lobe, which minimizes interference to (and from) stations
located outside the pattern. (The use of a directional antenna may
not be possible in a simplex peer-to-peer network, where all remotes
are designed to communicate with one another.)
3. If interference is suspected from a nearby licensed system (such as a
paging transmitter), it may be helpful to use horizontal polarization
of all antennas in the network. Because most other services use ver-
tical polarization in this band, an additional 20 dB of attenuation to
interference can be achieved by using horizontal polarization.

MDS 05-3301A01, Rev. C MDS 9810 Installation and Operation Guide 11
4. Multiple MDS 9810 systems can co-exist in proximity to each other
with only very minor interference as long as they are each assigned
a unique network address. Each network address has a different hop
pattern.
5. If constant interference is present in a particular frequency zone, it
may be necessary to “lock out” that zone from the radio’s hopping
pattern. The radio includes built-in software to help users identify
and remove blocked frequency zones from its hopping pattern. Refer
to the discussion of ZONE DATA (Page 49) and SKIP (Page 46) com-
mands for more information.
6. If interference problems persist even after removing blocked zones,
try reducing the length of data streams. Groups of short data streams
have a better chance of getting through in the presence of interfer-
ence than do long streams.
7. The power output of all radios in a system should be set for the low-
est level necessary for reliable communications. This lessens the
chance of causing unnecessary interference to nearby systems.
3.4 Antenna & Feedline Selection
Antennas
The equipment can be used with a number of antennas. The exact style
used depends on the physical size and layout of a system. Contact your
MDS representative for specific recommendations on antenna types and
hardware sources.
In general, an omnidirectional antenna (Figure 10) is used at the master
station site in an MAS system. This provides equal coverage to all of the
remote sites.
NOTE: Antenna polarization is important. If the wrong polarization is
used, a signal reduction of 20 dB or more will result. Most
systems using a gain-type omnidirectional antenna at the
master station employ vertical polarization of the signal; there-
fore, the remote antenna(s) must also be vertically polarized
(elements oriented perpendicular to the horizon).
When required, horizontally polarized omnidirectional
antennas are also available. Contact your MDS representative
for details.

12 MDS 9810 Installation and Operation Guide MDS 05-3301A01, Rev. C
Invisible place holder
Figure 10. Typical Omnidirectional Antenna
At remote sites and point-to-point systems, a directional antenna, such
as a Yagi is generally recommended to minimize interference to and
from other users. Antennas are available from a number of manufac-
turers.
Invisible place holder
Figure 11. Typical Yagi Antenna (mounted to mast)
Feedlines
The choice of feedline used with the antenna should be carefully consid-
ered. Poor-quality coaxial cables should be avoided, as they will
degrade system performance for both transmission and reception. The
cable should be kept as short as possible to minimize signal loss.
For cable runs of less than 20 feet (6 meters), or for short range trans-
mission, an inexpensive type such as Type RG8A/U may be acceptable.
Otherwise, we recommend using a low-loss cable type suited for 900
MHz, such as Heliax®.