Carlson Wireless Technologies FT 512 User Manual

Installation & User’s Manual

FT-512 Trailblazer

Multifunctional Digital Radio

Optional ADD-ONS Include:

4, POTS lines voice plug-in card

8, POTS lines voice plug-in card

1, Ethernet on-board port activation

3 Additional V.35 port plug-in card

Part Number 490-1600

Rev 1.09

Oct 2002

Trademark Information

i-WLL, the i-WLL logo , Trailblazer, the Trailblazer logo, are registered trademarks of
Carlson Wireless Technologies Inc.
Windows is a registered trademark of Microsoft Corporation,

US Headquarters:

1180-B Evergreen Road
Redway, CA 95560 USA

Presales Inquires and Applications Support

Please contact your local distributor or the Carlson Wireless sales department

Tel: [phone]
Fax: [phone]
Email: [e-mail]
URL: http://www.carlsonwireless.com

Customer Service, Product Support Information, and Training

Technical support is available Monday - Friday, 9:00 am to 4:30 pm, PDT.

Tel: [phone]
Email: [e-mail]
URL: http://www.carlsonwireless.com/support.html

Repair and Return

Carlson Wireless will replace or repair this product within two years from the date of
shipment if it does not meet its published specification, or if it fails while in service. A
return material authorization (RMA) is required prior to returning equipment to Carlson
Wireless.

Training

The Trailblazer support department offers training classes including overviews on:
applications engineering, in house testing, configuration, field testing and maintenance.
Please contact our customer support department for more specific details.

The information contained in this publication is the latest available, however, Carlson
Wireless reserves the right to change specifications of hardware and software without
prior notice. Purchasers of Carlson products should make their own evaluation to
determine the suitability of each such product for their specific application. Carlson
Wireless’s obligations regarding the use or application of its products shall be limited to
those commitments to the purchaser set forth in its Standard Terms and Conditions of
Sale for a delivered product. Use of this manual is also limited to the terms and conditions
stated in the contract between Carlson Wireless Inc. and the purchaser.

Copyright © 2002 Carlson Wireless, Inc. All Rights Reserved.

FT-512 Trailblazer Installation and User Manual version 1.09 ii

!

!

SAFETY WARNINGS

Potentially hazardous voltages exist on TELCO lines and associated equipment. Always observe
standard safety precautions during installation, operation, and maintenance of these products. To
avoid the possibility of electric shock, be sure to disconnect the power from the remote power
source before you perform any line connections or repairs. Always disconnect all the cables
connected to the system before disconnecting the grounding connection. After disconnecting the
power allow a few seconds for the internal capacitances to discharge before accessing the boards.

QUALIFIED PERSONNEL WARNING

The installation procedures described in this manual must be performed by qualified personnel
aware of the hazards involved. The personnel involved in equipment installation must be trained in
the installation of telephone equipment and associated power systems; these personnel must
strictly observe all the safety precautions related to the installation of communication equipment.
Never install, remove, or adjust equipment and associated cables. Do not work on roofs, masts, or
towers during a lightning storm.

ATTENTION! STATIC SENSITIVE DEVICES

PROPER HANDLING AND GROUNDING PRECAUTIONS REQUIRED.

Components within the Trailblazer system are sensitive to electrostatic discharge (ESD). To avoid
and prevent ESD damage and device failure maintain proper grounding during configuration, repair
or maintenance. This is achieved through the use of an antistatic wrist strap securely connected to
chassis ground. Do not use conductive tools for adjusting channel select switch.

Due to the energy radiated from the antenna, this product must never be mounted such that the
cabinet containing the antenna can be closer than 2 Meters ( 6.7 Feet ) to any person.

Never install telephone wiring during a lightning storm.
Never install telephone jacks in a wet location unless the jack is specifically designed for wet
locations.
Never touch telephone wires or terminals unless the telephone line has been disconnected at the
network interface.
Use caution when installing or modifying telephone lines.

UL INSTALLATION SAFETY INSTRUCTIONS

FCC, RF SAFETY HAZARD WARNING

FT-512 Trailblazer Installation and User Manual version 1.09 iii

Connection to the Telephone Network

The equipment complies with Part 68 of the FCC rules. You will find the label located on the
device. This label contains the FCC Registration Number and the Ringer Equivalence Number
((REN) for this equipment. You must, upon request, provide this information to your telephone
company.

The REN is useful to determine the quantity of devices that may be connected to the telephone line
and still have all of those devices ring with an incoming call signal. In most areas the sum of the
REN’s of all devices connected to one line should not exceed five (5.0). Confirm the number of
devices possible on the telephone line (in REN) by contacting the local telephone company who
provides the service.

Incidence of Harm

If your telephone equipment causes harm to the telephone network, the telephone company may
disconnect your service temporarily. If possible, they will notify you in advance. But if advance
notice is not practical, you will be notified as soon as possible. You will be informed of your right to
file a compliant with the FCC.

Rights of the Telephone Company

Your telephone company may make change in its facilities, equipment, operations or procedures
that could affect the proper functioning of your equipment. If they do, you will be notified in advance
to give you an opportunity to maintain uninterrupted telephone service.

Coin Service or Party Use Line

This equipment may not be used on the coin service provided by the telephone company.
Connection to party lines is subject to state tariffs.

Compliance and US Regulatory Information

CERTIFICATIONS AND REGULATORY

FCC Reg No., Part 68
FCC Reg No., Part 15
Industry Canada CS-03
Industry Canada RSS-210/139

BMD8 USA – 27773-PT-E
OPA-FT-512
3448-10241A
3448-FT-512

RADIO INTERFERENCE

Carlson Wireless USA Model: FT-512-Trailblazer

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. Changes of
modification not expressly approved by the party responsible for compliance could void the user’s
authority to operate the equipment.

FT-512 Trailblazer Installation and User Manual version 1.09 iv

Declaration of Conformity

Manufacturer’s Name: Carlson Wireless Technologies Inc.

Manufacturer’s Address: 1180–B Evergreen Rd.

Redway, CA 95560
USA

Declares that the product:

Product Name: FT-512 Trailblazer

Conforms to the following standard(s) or other normative document(s):

EMC:

FCC Part 15.247

Safety:

UL 1950

Supplementary Information:

Published Specifications

Redway, CA
July 20, 2002

Damon Siska
Director of Quality

FT-512 Trailblazer Installation and User Manual version 1.09 v

Table of Contents

______________________________________________________________________________

1 Introduction....................................................................................................1

1.1 Scope of Manual....................................................................................... 1

1.2 Functional Overview ................................................................................. 1

1.2.1 Main Features....................................................................................2

1.3 Optional Add-on Boards ...........................................................................3

1.3.1 Point to point......................................................................................3

1.3.2 Multipoint ...........................................................................................3

1.4 Application and System Design Considerations .......................................4

1.4.1 Point to Point Microwave Link............................................................4

1.4.2 Multipoint Microwave Link .................................................................4

1.5 General Specifications..............................................................................5

1.5.1 Block Diagram ................................................................................... 6

2 Installation...................................................................................................... 7

2.1 Unpacking.................................................................................................7

2.2 Site Requirements ....................................................................................7

2.2.1 Lightning Protection...........................................................................7

2.3 System Planning.......................................................................................7

2.3.1 Line of Sight, How to Tell for Sure? ...................................................7

2.3.2 Fresnel Zone, What is it, in plain English?.........................................8

2.3.3 Radio Path Losses ............................................................................9

2.3.4 Consideration of other devices in the 2.4 GHz ISM band ..................9

2.3.5 RF Cable Sizing and Recommendations......................................... 11

2.3.6 Data Cable Recommendations........................................................11

2.3.7 General Tools..................................................................................11

2.4 Quick Start Instructions...........................................................................12

2.4.1 Power connections to the FT-512....................................................12

2.4.2 Power Supply Feed Cable............................................................... 13

2.4.3 Connecting the optional CWT Battery Backed-up Supply ...............13

2.4.4 Channel Selection with the Manual Override Rotary Switch............ 16

2.5 Field Installation......................................................................................19

2.5.1 Bench Testing..................................................................................19

2.5.2 Mounting the Cabinet ......................................................................19

2.5.3 Synchronization of Co-located units ................................................19

3 Operation...................................................................................................... 19

3.1 Configuration with the Graphic User Interface ........................................19

3.1.1 Overview .........................................................................................19

3.1.2 Installation of FT-512 GUI CD in a computer................................... 19

3.1.3 Communications with the FT-512 and a computer .......................... 19

3.1.4 Running the FT-512 GUI CD in a computer ....................................20

3.1.5 Password Entry and Privileges........................................................20

3.1.6 Configuring the Basic Parameters...................................................20

FT-512 Trailblazer Installation and User Manual version 1.09 vi

3.1.7 Choosing Channel Configurations ...................................................23

3.1.8 Frequency Selection........................................................................23

3.1.9 POTS Lines and Onboard V.35 Port Setup .....................................24

3.1.10 QUAD V.35 Port Add-on Card Setup Information............................ 24

4 Test & Maintenance .....................................................................................25

4.1 Diagnostics .............................................................................................25

4.1.1 Description of Diagnostic Functions ................................................25

4.1.2 GUI Signal Strength and Packet Error Testing ................................25

4.1.3 System Information..........................................................................25

4.1.4 LED Function...................................................................................26

4.1.5 In Factory Tests...............................................................................26

4.2 Maintenance ...........................................................................................28

4.2.1 Installation of Software Upgrades....................................................28

4.2.2 Installation of Firmware Upgrades ...................................................28

4.3 Troubleshooting...................................................................................... 29

4.3.1 Units are on the Bench ....................................................................29

5 Product Accessories / Options...................................................................30

5.1 External Antenna - Professional Installers Only..................................... 30

5.1.1 Scope ..............................................................................................30

5.1.2 RF Safety Hazard Warning.............................................................. 30

5.1.3 Unpacking .......................................................................................30

5.1.4 Product Overview ............................................................................ 31

5.1.5 Installation .......................................................................................33

5.1.6 Mounting.......................................................................................... 34

6 Appendix ......................................................................................................35

6.1 About Carlson Wireless .......................................................................... 35

6.1.1 Mission ............................................................................................35

6.1.2 History .............................................................................................35

6.1.3 Summary .........................................................................................36

6.2 Technical Specifications N x 64 Serial Radio .........................................37

6.3 Technical Specifications 8 Line FXS plug in card ...................................39

6.4 Technical Specifications 8 Line FXS plug in card ...................................40

6.5 Cable Pin outs ........................................................................................41

6.5.1 Configuration Port Pin out ...............................................................41

6.5.2 Synchronization Port Pin out ..........................................................41

6.5.3 V.35 Port - Wiring the DB 25 to a Typical 34 pin Winchester ..........43

6.6 Warranty .................................................................................................44

6.7 Antenna Patterns.................................................................................... 45

6.7.1 Internal Antenna Patterns................................................................ 45

6.8 Acronyms/Abbreviations .........................................................................47

6.9 Glossary .................................................................................................49

FT-512 Trailblazer Installation and User Manual version 1.09 vii

List of Figures

_____________________________________________________________________________

Figure 1: Block Diagram .........................................................................................6

Figure 2: Close up of Power Connections............................................................. 12

Figure 3: Power Supply Connections....................................................................14

Figure 4: Main 6 Pair Cable Connector................................................................. 15

Figure 5: Battery Shown Connected to Power Supply ..........................................16

Figure 6: Channel Select Switch Location ............................................................17

Figure 7: Rotary Switch Identification with Channel 0 setting shown .................... 17

Figure 8: Mounting the Cabinet Outside ...............................................................19

Figure 9: Sync and Bus Port .................................................................................18

Figure 10: COM Port Selection ............................................................................. 20

Figure 11: Password Screen.................................................................................20

Figure 12 GUI – Configure Screen w/ Progress Bar at Bottom............................. 21

Figure 13: Selecting the Signaling Channel ..........................................................23

Figure 14: Selecting the Operating Channel .........................................................24

Figure 15: GUI - POTS lines and onboard V.35 port.............................................24

Figure 16: GUI - Quad V.35 Port Setup ................................................................24

Figure 17: GUI - Signal Strength and Channel Testing.........................................25

Figure 18: GUI - System Information ....................................................................25

Figure 19: System LED's ......................................................................................26

Figure 20: LED - D1 ..............................................................................................29

Figure 21: Mounting of Parabolic Grid 24 dBi Gain Antenna (Horizontally

Polarized).......................................................................................................35

Figure 22: 24 dBi External Antenna Diagram.......................................................35

Figure 23: V.35 Wiring Pin out .............................................................................. 43

Figure 24: Internal Antenna Patterns .................................................................... 45

Figure 25 : High Gain External Antenna Radiation Characteristics.......................46

List of Tables

_____________________________________________________________________________

Table 1: Fresnel Zone Chart ...................................................................................8

Table 2: Fade Margin Chart ....................................................................................9

Table 3: Coax Cable Loss Table...........................................................................11

Table 4: Feed Cable Sizing and Distance - FT-512 alone ....................................13

Table 5: Pin out for Battery Backed up Power Supply ..........................................15

Table 6: Switch Position Frequency Defaults........................................................18

Table 7: Channel Selection Table .........................................................................23

FT-512 Trailblazer Installation and User Manual version 1.09 viii

FT-512 Trailblazer Installation and User Manual version 1.09 ix

1 Introduction

1.1 Scope of Manual

The purpose of this manual is to provide planning and installation personnel with
the appropriate procedures to plan and install the FT-512 Trailblazer Digital
Microwave Radio. To avoid harm to persons or damage to the product please
ensure that you have read through the safety, unpacking and installation sections
before proceeding.

1.2 Functional Overview

The FT-512 provides a reliable, wireless voice and high-speed data connection
up to a distance of 50 km. This radio is specifically designed for easy integration
with our voice and data multiplexer cards, or any standard V.35 serial device. In
addition, Carlson Wireless Technologies Inc. (CWT) also offers a multipoint card
cage that will link together the serial data through our network interface card
allowing up to 4 E1’s/T1’s connection into the public switched telephone network.
CWT can provide excellent price/performance solutions for many of the worlds
telecommunication needs both in a point to point or point to multipoint topologies.

The initial release is using a 2.4 GHz radio frequency band, however others are
scheduled to follow in the 3.5 and 5.7 GHz radio bands in 1Q2003.

FT-512 Trailblazer Installation and User Manual version 1.09 1

1.2.1 Main Features

512 or 256 kb/s Synchronous Data Stream with Frame Sync – Structured for

high quality PCM voice use, V.35 serial data peripherals, or optionally an 10
MB/s Ethernet network port.

Full configurable through a PC – Simplify the setup using our Graphics User
Interface application – Data speed, CDMA code, Clocking, Master/Slave and
selection of the user frequency pool are configurable in minutes with a serial
Com port.

Repeater – This product can act as a repeater by just connecting the serial data
port back to back with another unit and setting the external clock to yes on the
master side.

Standard ISO 2593 V.35 DTE port – plugs right in to most V.35 devices

Low Power Draw – The FT-512 uses between ½ to 2 watts of power and

accepts any voltage between 12 and 48 VDC.

Very Expandable- You can start out with only one link and, utilizing a card cage,
continue to add cards linking together the data and thus gain the features of a
point to multipoint topology. Thus you can continue expanding without loosing
any of your original investment.

Private and Secure – Encrypted CDMA spread spectrum modulation,
proprietary framing, structure and packet size assures complete privacy.

Wire-line Quality Voice and Data – Data speeds are selectable up to 512 kb/s.
Designed to integrate seamlessly with our full bandwidth 64kb PCM POTS cards
for high quality voice line/trunks.

Optional 10 MB/s Ethernet port on-board - For simultaneous LAN / IP data
and PCM voice needs

Affordable – The “per pair” pricing of the FT-512 is comparable to the “single
unit” of other data radios not designed for voice and PSTN integration.

FT-512 Trailblazer Installation and User Manual version 1.09 2

1.3 Optional Add-on Boards

1.3.1 Point to point

The FT-512 is a powerful voice and/or data machine that can operate as a stand
alone point to point microwave link. Optional voice and data plug-in cards are
also available for your current and future growing needs:

4, POTS lines voice plug-in card

Four, full bandwidth 64kb PCM, POTS lines can be extended to one location,
eliminating the need for external multiplexers.

8, POTS lines voice plug-in card

Eight, POTS lines can be extended to one location, eliminating the need for
external multiplexers and can be configured as full bandwidth 64kb PCM or 32kb
ADPCM to accommodate your data needs as well!

1, 10BaseT, Ethernet bridge port

With this unique option, line quality circuit switched voice can be used along with
high-speed LAN data traffic, possibly eliminating the need of a router!

4, port, shared V.35 data plug-in card

Why set-up several individual data links when you can extend four data ports to
one location and share the cost between customers?

1.3.2 Multipoint

18 Slot Card Cage with 100 watt power supply

You can have up to 15 villages, each served with up to 8, 64 kb PCM non
blocking telephone lines/trunks integrated into one card cage along with an E1 or
T1 direct digital connection. 1 or 2 time slots can be used for providing Internet.

4 E1, V52, Network Interface Card

With this optional Card Cage and 4 E1, Network Interface Card, you can provide
up to 120 users with high quality voice and high speed Internet connectivity along
with remote monitoring and diagnostics.

4 T1, GR303, Network Interface Card

With this optional Card Cage and 4 T1, Network Interface Card, you can provide
up to 96 users with high quality voice and high speed Internet connectivity along
with remote monitoring and diagnostics.

FT-512 Trailblazer Installation and User Manual version 1.09 3

1.4 Application and System Design Considerations

1.4.1 Point to Point Microwave Link

Security Monitoring Cameras
Public Safety Data Links
Point to Point Commercial Data Links
Cellular Backhaul Data Needs
Permanent or Temporary Telephone Service
Emergency and Disaster Relief
Public Calling Phones
Leased Line Emulation
Islands and other Isolated Areas

1.4.2 Multipoint Microwave Link

Internet Café and Telephone Calling Centers
Wireless Digital Local Loop (Rural Telephone)

FT-512 Trailblazer Installation and User Manual version 1.09 4

1.5 General Specifications

Note: More technical details are found in the Appendix of this manual

Data Interfaces

Primary Serial Data Port V.35 using a DB 25 Connector (RS-422/RS-

232)
Data Rate and Type 256/512 kbps, Synchronous
Command Port RS-232, 9600 bps, N,8,1
Latency less than 5 ms.

Power Requirements

Input Voltage 12 to 48 Vdc
Power Consumption 2 Watts in full operation (does not include add-

on cards)

RF Specifications

RF Frequency Band 2.400 to 2.4835 GHz

2.350 to 2.500 Optional for export only!
RF Channels Programmable in 1 MHz steps
RF Signal Bandwidth 12 MHz (7 non overlapping channels)
PN Code Rate 11 M chip/sec
PN Code Length 16
Spreading codes 4 programmable non orthogonal codes
Processing Gain 12.04 dB
Modulation Type BPSK (256) or QPSK (512kbs) DSSS
Transmitter Output Power +17dBm, set to allow CDMA operation
Receiver Sensitivity (10

Operating Temp -30 to +60 Degrees C with solar shielding

Mechanical

PCB dimensions 5 in. x 6 in. x 1 in.
PCB weight 0.5 lbs

-6

BER) -93 dBm @ 256 kbps, -90 dBm @ 512 kbps

FT-512 Trailblazer Installation and User Manual version 1.09 5

1.5.1 Block Diagram

Figure 1: Block Diagram

FT-512 Trailblazer Installation and User Manual version 1.09 6

2 Installation

2.1 Unpacking

The FT-512 Trailblazer radio will arrive in one box approximately 19 x 15x 13
inches (47 x 37 x 32 cm). Small amounts of feed cable and/or power supplies
may also be included in this box if ordered.

Caution! Observe static precautions when wiring or handling circuit boards.

!

There are nylon standoffs holding the antenna element to the reflector plate.
These are fragile and can easily be over-tightened. They are set to a specific
torque and if over-tightened may fail.

2.2 Site Requirements

2.2.1 Lightning Protection

The FT-512 is equipped with secondary lightning protection only. If your feed
cable is more than 10 Meters (35 ft) in length or extends beyond the existing

!

building you will need a primary gas discharge type lightning protector. Contact
your sales representative for more information.

2.3 System Planning

2.3.1 Line of Sight, How to Tell for Sure?

Microwave engineers will use a variety of ways to calculate the losses in a radio
path. Determining line of sight is easy if the path has a visible landmark at one
end. If that is not the case then one can resort to topographical maps and plot a
path. If this is marginal you still may have to prove the maps accuracy. We have
used a mirror as a reflector if a sunny day or if at night a bright spotlight. Even
with line of sight proven there are two more things you must know, distance and
clearance of first Fresnel zone.

FT-512 Trailblazer Installation and User Manual version 1.09 7

2.3.2

Fresnel Zone, What is it, in plain English?

In plotting terrain profiles for microwave frequencies, there are both direct and
deflected waves that converge upon the receiving point. The direct path has a
predictable behavior. Calculating losses from indirect or “deflected” signals
however requires a different approach.

To calculate the losses of the indirect signals, let us look at what occurs. As the
signal cone spreads outward from the transmitting point, it becomes increasingly
delayed from the original. That delay will show up as a phase change from the
original. As that phase approaches 180 degrees, this delayed signal will have a
significant phase-canceling effect on the direct signal. As the signal continues to
widen, peaks and troughs in reception strength similar to a sine wave occur.
Each peak and trough is called a Fresnel zone.

The first Fresnel zone is the radius of the signal cone in which the phase angle of
the signal can be delayed from 0 to as much as 90 degrees. This is where the
majority of the signal power is supposed to exist. The second Fresnel zone will
cover from 90 to 270 degrees and is undesired as it only causes the negative
effect of phase canceling. The third zone will have signal delays from 270 to 450
degrees. The effect is that odd number zones will add to the direct signal and
even number zones will subtract.

Zone Frequency Wavelength Distance to start Distance to end Fresnel Radius 60% of Zone

(MHz) (feet) (miles) (km) (miles) (km) (feet) (m) (feet) (m)

1 2400 0.41 2.0 3.2 2.0 3.2 46.53 14.18 27.92 8.51
2 2400 0.41 2.0 3.2 2.0 3.2 65.80 20.06 39.48 12.03
1 2400 0.41 1.5 2.4 4.5 7.2 49.35 15.04 29.61 9.03
1 2400 0.41 3.0 4.8 3.0 4.8 56.98 17.37 34.19 10.42
1 2400 0.41 4.0 6.4 10.0 16.0 78.65 23.97 47.19 14.38
1 2400 0.41 6.0 9.6 6.0 9.6 80.59 24.56 48.35 14.74
1 2400 0.41 12.0 19.2 12.0 19.2 113.97 34.74 68.38 20.84

Table 1: Fresnel Zone Chart

Some examples are given in the table above. Download the MS Excel file located
on the CWT web site at www.carlsonwireless.com/support.html to calculate your
own path. Remember, 60% or more of the first Fresnel zone needs to be clear
from obstructions for the calculation of free space losses to be accurate.

You can set the Fresnel zone to even numbered values when plotting a profile to
see potential areas of destructive signal reflection present on the path. One can
now see how it is possible to improve your path by optimizing the height of

FT-512 Trailblazer Installation and User Manual version 1.09 8

antennas so that the first Fresnel zone signal path is clear and the second is
obstructed.

2.3.3 Radio Path Losses

After confirming not only line of sight and adequate Fresnel zone clearance, it is
then time to look at the Free Space Loss of the radio signal, RF cable losses,
and antenna gains to determine how much is left over. The remaining signal is
called the “Fade Margin”.

Distance Distance Ant Gain Ext RF Path Loss RF power ERP Link Margin

in miles in km in dBi Cable(s) in dB in dBm in dBm in dB

1.5 2.4 14.0 0.0 108 17 31 28.0

2.0 3.2 14.0 0.0 110 17 31 25.5

5.0 8.0 14.0 0.0 118 17 31 17.6

8.0 12.9 14.0 0.0 122 17 31 13.5

10.0 16.1 14.0 0.0 124 17 31 11.5

12.0 19.3 14.0 0.0 126 17 31 10.0

14.0 22.5 14.0 0.0 127 17 31 8.6

20.0 32.2 24.0 1.4 130 17 41 24.1

35.0 56.3 24.0 1.4 135 17 41 19.3

50.0 80.5 24.0 1.4 138 17 41 16.2

Table 2: Fade Margin Chart

The above chart shows various antenna and distance combinations. A
changeable Excel spreadsheet is available on the world wide web at

www.carlsonwireless.com/support.html The 24 dB gain external antenna option

is only available through factory trained dealers.

What’s an acceptable “Link Margin“? A rule of thumb theory is that 10 dB of fade
margin will deliver about 90% reliability and 20 dB will deliver about 99%
reliability, etc. Multi-path and polarization will affect the link as well. At 2.4 GHz
there is only a small ground wave component involved in the radio propagation,
hence the above numbers presume both clear LOS (line of sight) and clearing at
least 60% of the first Fresnel zone. Multi-path degradation is the reason why a
minimum of 16 to 20 dB of margin is required for the link.

2.3.4 Consideration of other devices in the 2.4 GHz ISM band

The ISM (Industrial, Scientific, and Medical) band at 2.400-2.483 GHz is an
unlicensed band shared for many uses. Any of these devices could become a
source of interference for the Trailblazer products. Some examples are
described here:

Video Transmitters

FT-512 Trailblazer Installation and User Manual version 1.09 9

These devices use analog radios which are usually fixed in frequency, 6 to
10 MHz bandwidth, low power with an ERP* of less then +10dBm.

Cordless phones

These devices are narrow band and fixed in frequency (during each use),
a 1 to 2 MHz bandwidth, low power with an ERP of less then +10dBm. It
is strongly recommended to avoid the use of 2.4GHz cordless phones in
the vicinity of Trailblazer products.

Local Area Network (Lan) Bridges

These devices are true spread spectrum devices, either a 1 MHz
bandwidth frequency hopping (FH) over the complete band or a CDMA
type of a 16 MHz bandwidth and stationary. ERP’s can range up into the
+30’s (dBm).

Microwave ovens

Microwave oven outputs have been measured at levels up to +20dBm
ERP. This power consists of narrow pulses sweeping wildly in frequency
due to the circulators built into the ovens. The higher power spikes are
mostly concentrated in the upper half of the band between 2450 and 2485
MHz.

Fortunately few users of 2.4 GHz products are located in rural areas, leaving
sharing concerns down to consumer microwave ovens, LAN’s and other rural
telephone users. The functionality of the FT-512 Trailblazer system depends on
the existing and forecasted spectrum usage in the radio path. Due to the
characteristics of the spread spectrum radio, the ITU (International
Telecommunication Union) was able to coordinate this band globally for
unlicensed use. All users in the band must accept all other signals within the
band, interfering or not.

How this impacts the CDMA/FDMA technology used in the FT-512:

If the interfering signal is stationary and has a bandwidth less than 3 MHz it will
not create any significant problem even if it is 100 times (20dB) stronger than the
receive threshold. If the interfering signal has a bandwidth wider than 4 MHz and
is 10 times (10dB) stronger than the receive threshold, it can render that
channel(s) unusable. If the interfering signal is hopping from frequency to
frequency throughout the band such as the LAN bridge device and is only 1/10 (–
10dB) as strong as the receive threshold, it can cause significant dropouts.

FT-512 Trailblazer Installation and User Manual version 1.09 10