Radio Frequency Systems 48900 48910, 48920 and 48930 Bi-directional amplifiers User Manual 48900manual
Radio Frequency Systems Inc 48910, 48920 and 48930 Bi-directional amplifiers 48900manual
Users guide
48910, 920, 930
User's Manual
200 Pondview Drive, Meriden, CT 06450 • (877) 737-9675 • Fax (203) 821-3852
www.rfsworld.com
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Disclaimer
All information and statements contained herein are accurate to the best of the knowledge of Radio Frequency
Systems, but Radio Frequency Systems does not make any warranty with respect thereto, including without
limitation any results, which may be obtained from the products described herein or the infringement by such
products of any proprietary rights of any persons. Use or application of such information or statements is at
the user’s sole risk, without any liability on the part of Radio Frequency Systems. Nothing herein shall be
construed as license of or recommendation for use, which infringes upon any proprietary rights of any person.
Product material and specifications are subject to change without notice. All sales of the products described
herein are subject to Radio Frequency System's standard terms of sale and the specific terms of any
particular sale.
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TABLE OF CONTENTS
GENERAL STATEMENTS.................................................................................................................................. 4
MAXIMUM PERMISSIBLE EXPOSURE LIMITS........................................................................ 5
PRODUCT OVERVIEW........................................................................................................................................... 6
FIELD TUNE-UP, ALIGNMENT OR CALIBRATION ........................................................................................................... 6
FCC ID AND CANADA CERTIFICATION NUMBERS ...................................................................................................... 6
THEORY OF OPERATION ........................................................................................................................................................ 7
ELECTRICAL SPECIFICATIONS............................................................................................................................................. 8
MECHANICAL SPECIFICATIONS ........................................................................................................................................... 8
ENVIRONMENTAL SPECIFICATIONS................................................................................................................................... 8
INTERMODULATION, POWER, AND AGC......................................................................................................................... 9
AGC AUTOMATIC SHUTDOWN.......................................................................................................................................... 10
MANUAL GAIN ADJUSTMENT ............................................................................................................................................. 10
AC/DC POWER....................................................................................................................................................................... 10
GROUNDING AND SURGE PROTECTION ........................................................................................................................ 10
EXTERNAL FILTER PORTS .................................................................................................................................................. 11
INSTALLATION............................................................................................................................................................. 11
ANTENNA ISOLATION............................................................................................................................................................. 13
DIAGNOSTICS/TROUBLESHOOTING.............................................................................................. 13
TEST POINT DESCRIPTIONS.............................................................................................................................................................. 13
FACEPLATE ............................................................................................................................................................................... 13
COMPONENT LOCATION................................................................................................................................ 14
MAINTENANCE, REPAIR AND WARRANTY............................................................................ 15
44
General Statements
Thank you for selecting this RFS product. We are confident that you will find this product in proper
working order, meeting all stated specifications. If not, please contact customer service immediately
at 1-800-321-4700 and we will resolve the issue without hesitation.
Please read this manual. A full understanding of product operation will support optimal performance
and prevent accidental damage not covered by the stated warranty.
§ Do not operate this product without proper loads on both antenna ports. You must connect
both antenna ports to an antenna or a 50-Ohm load, rated for at least 1 watt.
§ These products receive and amplify RF signals. As such, these products are intended for use
by the licensee of the respective service and should not be used without the expressed
permission of the licensee.
§ Do not remove the cover for service. There are no internal adjustments. Path manual gain
adjustment access holes are clearly marked on the bottom. Under normal circumstances,
you need not make any adjustments. For more information, see installation section.
§ The terminology “RX” and “TX” are being replaced by “UL” for uplink and “DL” for downlink
respectively.
The 48900 series bi-directional amplifiers/ repeaters/signal boosters are designed and optimized for
low cost, high reliability, and ease of use. This manual provides information on the proper operation
and care; however, Radio Frequency Systems can provide the total package of components and
hardware for any type of repeater installation. See our catalog for the full line of antennas, coaxial
cables, and accessories at www.rfsamericas.com. To achieve the best possible coverage, contact
RFS Applications Engineering at 1-800-659-1880 for technical assistance and/or design of the
distribution network.
Ground Kit
Donor
Antenna
For distribution network design assistance, contact RFS Applications Engineering at 1-800-659-1880.
55
Maximum Permissible Exposure Limits
THIS PRODUCT IS CATEGORICALLY EXCLUDED FROM ROUTINE ENVIRONMENTAL
EVALUATION ACCORDING TO CFR 47, SECTION 1.1037.
Repeaters like the 48900 series generate radio signals and thereby give rise to electromagnetic
fields. The installer is expected to have a complete understanding of CFR Title 47, Sections 1.1307
and 1.1310. A brief discussion follows but is not intended to be a substitute. Additional information
can also be obtained from OET Bulletin 65.
§ Antenna installation should be performed by qualified technicians only.
§ Installation instructions are not optional and are for the purpose of satisfying FCC RF
Exposure Compliance.
§ All antennas (donor and service) are to be fixed-mounted and physically secured to one
location.
§ Maximum donor antenna gain is 28 dB.
§ Non building-mounted donor antennas must be greater than 10 meters above ground.
§ Maximum service area antenna ERP is 1.0 Watt.
§ Minimum separation to any body part of any person is 25cm.
There are two types of antennas attached to this unit. The donor antenna is typically roof mounted
and the service antenna is usually mounted in a publicly accessible area. Both antennas should be
fixed mounted. Installation considerations for both of these will be discussed separately.
Donor antennas receive the base site TX signals and transmit the mobile TX signals back to the base
site (uplink paths). These are typically mounted on rooftops or tower structures. The maximum
composite power of the uplink path is 160 mW (+22dBm). Section 1.307(b)(1) excludes from routine
environmental evaluation, facilities, operations and transmitters that, according to Table 1 (titled
"Cellular Radiotelephone Service"), are less than 1000W ERP for building mounted antennas and
less than 1000W and greater than 10 meters above ground for non building-mounted antennas. As
such, with maximum power from the uplink path @ 160 mW (+22dBm) and a maximum antenna gain
of 28 dB, the donor antenna installation will not exceed 1000 Watts (+60 dBm) and is categorically
excluded.
However, according to Section 1.1307 (b)(1), the appropriate exposure limits of 1.1310 are applicable
to all facilities, operations, and transmitters. Therefore, the MPE (Maximum Permissible Exposure) of
Section 1.1310 applies to the donor antenna installation. OET Bulletin 65 provides methods of
calculating power density based upon the ERP and distance. It would be impossible to cover every
possible configuration in this manual. Likewise, it would be unreasonable to dictate the exact
parameters of every installation; therefore, it is the responsibility of the qualified technician to know
and ensure that Sections 1.1307 and 1.1310 of CFR Title 47 are being met.
The following scenario is a typical rooftop installation in an uncontrolled area (worst-case) using a 18
dB gain donor antenna. The MPE @ 824 MHz is 0.549 mW per cm2. The uplink is being driven to its
66
maximum output power (+22 dBm); the resultant ERP is +40 dBm or 10,000 mW. OET Bulletin 65
provides the following formula for calculating the power density with the EPA recommended factor for
ground reflection:
1.05 ERP/ π R2
Where R is the distance to center (of any body part of person).
Solving for 10,000 mW @ 3ft. (91.44 cm) we get a power density of 0.4 mW per cm2.
The Yagi antenna in this scenario must be mounted in such a way that no body part of any person
may come closer than 3 feet in the direction of the main power beam. This will limit exposure to well
within the MPE.
Service antennas are also fixed mounted and covered by the same MPE considerations as the donor
antenna. However, this assumes that the area is always general population/uncontrolled and that the
minimum distance in most installations will be less than 3 feet. According to Table 1(B) of Section
1.1310, the power density @ 894 MHz is 0.596 mW/cm2. The maximum power of the 48900
downlink (base to service area) is +22 dBm (160 mW). Assuming no feeder cable loss and a service
area antenna gain of 8 dB, a safe minimum separation of 10 inches (25 cm) is required to stay within
the MPE.
1.05 x 1000 mW/3.14 x 252 = 1050/1962.5 =0.535 mW/cm2
Therefore, the service area antenna should be mounted such that no body parts of any person may
come closer than 10 inches (or 25 cm). The service area antenna gain is 8 dB in the example above,
but may be increased to make up for cable and/or splitter or tap losses. For example, if a 2-way
splitter is used to provide for two antennas in different parts of the service area, then the antenna gain
may be increased to 11 dB to make up for the loss of the splitter 3.6 dB. The maximum service area
antenna gain for any specific location can be calculated as follows:
8dB+ accumulated losses to the antenna.
Product Overview
Field Tune-up, Alignment or Calibration
There is no field tune-up or calibration necessary. These units are aligned and calibrated at the time
of manufacture and are designed to retain calibration throughout the life of the product.
FCC ID and Canada Certification Numbers
The listed models have been tested and granted certification by the FCC in accordance with CFR
Title 47, Part 90 and by the DOC in accordance with RS 131, Issue 131.
The FCC identification number for each particular model appears on a label on the faceplate of the
unit. Applicable FCC identification and Canadian ISC numbers are as shown:
FCC ID Canada
IWD48900 TBD
77
Theory of Operation
The 48900 signal boosters are designed to enhance radio communication in buildings, basements,
tunnels and other RF shielded environments. The 48910 is tuned for the 800 MHz Cellular band, the
48920 for the 800 SMR band and the 48930 for the 900 MHz SMR band.
These units work by receiving and amplifying the base TX signals via a donor antenna directed at the
desired base site. This RF path is called the downlink. The amplified base TX signal is re-radiated via
antenna(s) or radiating cable into the Service Area. Subscriber mobile RF signals are received by the
same service area radiating elements and amplified in the uplink RF path to be radiated back to the
base via the donor antenna.
The LNAs and Power Amplifiers are broadband. The same amplifiers are used for the uplink and
downlin. Likewise, the control board is the same for both models. Differentiation is provided by the
duplexing filters on the base and service area connectors that determine the basic passband and
direct the RF signals to the proper gain path, uplink and downlink respectively.
Both the downlink and uplink have Automatic Gain Control (AGC) in the power amplifiers to prevent
an overdrive condition. Manual gain adjustment is provided in the LNA stage. Overdrive limiting is
provided by the AGC circuitry and set at the factory. This ensures that the unit will not exceed FCC
limits for spurious emissions.
The control board distributes DC power to the amplifier modules and monitors each module for any
fault conditions. LED indicators provide visual diagnostics and a NC / NO relay provides for remote
notification for any fault condition.
Block Diagram
88
Electrical Specifications
Downlink Uplink
48910 Freq, MHz 869-894 824-849
48920 Freq, MHz 851-869 806-824
48930 Freq, MHz 935-941 896-901
Gain, no attenuation 65 dB 65 dB
Gain Flatness, typical ±2.0 dB ±2.0 dB
Manual Attenuator Range 20 dB 20 dB
Output Limiter Range, Automatic* 20 dB 20 dB
Noise Figure, typical** 4.0 dB 4.0 dB
Composite Power, typical* +22 dBm +22 dBm
iDEN, CDMA, typical +19 dBm +19 dBm
Impedance 50 Ohms 50 Ohms
VSWR, input 1.5 1.5
Propagation Delay, worst case at band edge <0.5 microsecond <0.5 microsecond
Power, 120/220 Auto Ranging, IEC-320 Socket 110 VAC@ .3 A
*AGC circuitry monitors the output power and reduces the gain to prevent overdrive and oscillation.
**No attenuation and at room temperature.
Mechanical Specifications
Connectors, RF N Female
Weight 17 lbs (7.65 kg)
Size, L x W x D 15.5 x 11.54 x 5.7 Inches (39.4 x 29.3 x 14.5 cm)
Diagnostics Power, AGC Overdrive, and Fault LEDs
Environmental Specifications
Operating Temperature, ambient -10 to +45 °C
Maximum humidity 95% RH (non condensing)
Environmental Rating Similar to NEMA 3R
99
Intermodulation, Power, and AGC
Per CFR Title 47, Part 90, there shall be no spurious emissions greater than {43+ 10 Log 10 (Power
Out Watts)} dB below the carrier Power Out (dB) level. This is always equivalent to -13 dBm.
The primary contributor to spurious emissions is multiple signal intermodulation. As multiple signals
are amplified, they generate intermodulation products (IM). The level of IM is a factor of the amplifiers
linearity or 3rd Order Intercept Point (IP3), and the number and power of signals being amplified
(Pout).
IM = 3xPout - 2xIP3
‘Pout’ is the combined power of all the signals in the passband known as the composite power. Radio
Frequency Systems, Inc. has designed the 48900 signal boosters using a combination of low
distortion amplifiers and automatic gain control (AGC) to achieve maximum output while
automatically limiting spurious intermodulation levels to -13 dBm or less for any number/power
combination of signals.
The AGC circuitry is housed in each power amplifier stage. A detector on the output of the amplifier
provides a DC voltage proportional to the output power. This voltage is compared to a factory setting.
As long as this voltage is less than the setting, no action is required. However, when the combination
of signal level and or number of signals causes the composite power to exceed the safe level, the
AGC's comparator generates a DC voltage to a pin diode attenuator that increases attenuation in
proportion to the level of the DC voltage.
The attenuation reduces the output power until the detector voltage is at a safe level again. If the
number or power of the signals is reduced, the DC offset voltage will reduce the level of attenuation.
In typical operation, the AGC is only active when needed to prevent overdrive. If the AGC is
constantly activating, RFS suggests that you reduce the gain via the manual attenuator and verify
that an oscillation between the base and service antenna systems does not exist.
AGC in the uplink is rarely needed in modern radio installations. As a portable comes closer to the
internal antenna network, its signal becomes stronger at the base site. Typically, the dynamic power
control at the base will turn the portable's power down to reduce interference and conserve power.
Overdrive is more likely to occur on the downlink path. All active signals at the donor base site will be
amplified by the repeater regardless of whether or not they are in use in the service area. Ideally, the
donor antenna is directional. This limits the number of donor base sites the repeater recognizes and
reduces the potential for interference. RFS recommends that you observe the signal levels before
connecting the repeater. Out of band signals can also cause overdrive. The most likely cause of an
overdrive condition is oscillation from inadequate antenna isolation.
Table 1 lists the typical output power per signal, which can be expected from the 48900 for a given
number of active signals operating at equal input levels. For a donor site that has 16 signals, the
power per signal would be +9 dBm, assuming the incoming signal is sufficient so that that level will be
achieved.
Number of signals dBm
1 22.0
2 19.0
4 15.0
8 12.0
16 9.0
32 6.0
64 2.0
TABLE 1: TYPICAL OUTPUT POWER PER SIGNAL
1010
In all cases, the actual signal output power is equal to the input signal power plus the gain of the
repeater. If a signal level of -80 dBm exists at the input to the repeater and the gain is 65 dB, the
resulting output will be –15 dBm dBm, not +9 as noted in the previous paragraph. +9 dBm in this
case is the maximum output for 16 channels.
AGC Automatic Shutdown
When the automatic gain control circuit reaches its limit (25 dB typ), the power amplifier stage is shut
down to prevent harmful distortion and potential damage to the booster. Shutdown will occur if the
AGC control limit is exceeded for about 1/2 second. Power is then cut for two seconds. After this
timeout, power is brought back on-line. If the overload condition is still present, shutdown will again
occur in approximately one second. This cycle will be repeated until the condition causing AGC to
reach its limit is removed. Conditions that can cause AGC to reach its limit include the presence of
one or more very strong channels, a strong in-band noise source, or amplifier oscillation due to
inadequate antenna isolation.
Manual Gain Adjustment
The independent manual attenuators, RX for uplink and TX for downlink, are accessible from the
bottom of the unit. These are pre-set in the fully counterclockwise position, at minimum attenuation,
maximum gain. Manual attenuation is separate from the AGC so these attenuators can be used to
reduce overdrive while maintaining AGC range. At the full clockwise position, 20 dB of attenuation will
be introduced in the respective gain path.
AC/DC Power
AC power is supplied through a standard 3-wire male plug connected through a standard IEC-320
plug. Connect this plug to any standard 3-wire 120-240 VAC outlet. A 5x20 mm, .315 amp 250VAC
slow-blow fuse is used. A 2 amp, 32 VDC, fast-acting fuse is located on the side of each amplifier to
protect the DC voltage path. (See “Component Location”)
Ö Always unplug the amplifier before servicing the interior.
Ö Never insert conductive objects into any opening.
Ö Never remove or probe under the plastic safety shield covering the AC terminals of the 24
VDC power supply.
Ö Always use a standard 3-wire electrical outlet, with safety ground, for connection to AC
power.
Grounding and Surge Protection
The unit is case grounded through the three-prong plug. The donor antenna feeder cable should
have a cable ground attached to it, along with an inline surge arrestor between the donor antenna
and the 48900. The distribution network need not be grounded in building installations. However, the
distribution network in tunnels, subways or outdoor installations should also include a cable ground
and inline surge arrestor at or near the “service” port.
DANGER
Always remove power before checking or changing fuses. 120VAC can be lethal.
1111
External Filter Ports
SMA female connectors on the faceplate of the 48900 allow for connection of externally mounted
passive 50 Ohm filtering. The external filter then modifies the related passband. Should the
conditions change in the field, the external filter can be removed or replaced with minimal interruption
in service. RFS has a variety of filter options, see the application notes on our website of contact RFS
Applications Engineering for assistance. Separate ports are provided for both the uplink and
downlink.
Two jumpers are required to connect an external filter. One connector on the jumper must be an
SMA male to connect to the 48900; the other connector type will depend on the connector on the
filter. Ensure that the external filter is mounted close enough so that the jumpers will reach the
repeater without undue stress or crimping. Disconnect power from the repeater, then disconnect the
jumper from the uplink or downlink as needed. Connect the external filter and reconnect power to the
unit. The passband filter will modify the passband of the link.
Installation
§ Choose an optimal location.
The choice of a location for the 48900 to reside is often dictated by circumstance. These units
can withstand a wide range of environmental conditions, but a cooler environment will increase
the life of the product. The 48900s are not intended for outdoor operation without protection.
Furthermore, a stacking room near a riser for easy access to the roof and other floors is desired.
However, access to clean 110/220 VAC power is the only requirement.
§ Install directional donor antenna and align with desired base site.
Yagis, corner reflectors and panel antennas work best. The 48900s have sufficient filtering to
prevent undesired signals from causing interference; however, it is best to reduce the chance for
interference by directing the mobile signals only towards the desired base site.
§ Check the incoming signal before connecting.
The product will work with a wide range of RF input signal levels. Ideal levels on the downlink are
in the range of -60 dBm. These levels will provide a maximum output power while not causing
significant overdrive. Also, check for extremely strong out-of-band signals. These may overdrive
the filtering and cause gain reduction.
§ Connect the donor antenna to the 48900 via a 50-ohm coaxial cable.
Size and type of cable are a matter of choice. Typically, 1/2" Flexwell foam coax is used, plenum
rated for inside buildings and work areas. However, 7/8" cable may be used to reduce
longitudinal loss. Superflex cables are easier to install but have higher longitudinal loss.
WARNING
Do not connect AC power until antennas have been connected to both the base and
service area ports.
1212
§ Install service area antenna(s).
Determining the location and type of service area antennas is part of the distribution system
design. Generally, it is desired to minimize the amount of coax that has to be installed. However,
in buildings with extensive obstructions, it may be necessary to install several service area
antennas. For assistance with antenna placement, contact RFS Applications Engineering.
§ Mount repeater upright, with the connections toward the floor.
Ensure there is sufficient space above and below the unit to allow airflow through the heat sink.
Check to make sure the AC power cord can reach the power source. Also, provide adequate
bending radii for the coaxial cables.
§ Connect service antenna(s) to "Service" via a 50-ohm coaxial cable.
Multiple service area antennas/radiating cable runs may be connected to the 48900. Splitters and
taps may be used to accommodate unique distribution systems. RFS has all the components
needed to complete even the largest installations. Visit our website at: www.rfsworld.com, or call
us.
§ Connect the donor antenna cable to "Base".
§ Connect AC power to the unit and observe power and fault LEDs
§ Adjust manual gain .
If the yellow DL AGC LED is lit then it is suggested that you reduce the gain in the DL via the
manual attenuator. Turn the adjustment clockwise to reduce gain until the AGC LED goes out.
Then adjust the UL gain to the same setting to minimize noise generated in the uplink.
If both LEDs are lit then there is likely a oscillation between the antennas – see “Antenna
Isolation”. Also read the section on “Intermodulation, Power, and AGC”
§ Test the installation.
This test should include multiple subscribers in various locations of the service area. It should
also include one subscriber in fairly close proximity to the repeater. This test will check to ensure
that a nearby user does not overdrive the uplink and reduce coverage for the other users.
If the UL AGC LED lits during the system test it most likely indicates that there is a hot spot in the
service area where the subscriber signal is overdriving the uplink. It is best to minimize this effect
by relocating the nearest service antenna or adding a attenuator pad to reduce the UL signal
strength.
IMPORTANT
Observe Maximum Permissible Exposure cautions when determining the type and
location of all antennas.
1313
Antenna Isolation
Isolation between the donor (base) antenna and service area antenna should be 20 dB greater
than the gain of the repeater amplifier.
If the isolation is less than the amplifier gain, then positive feedback sufficient for oscillation is present
in the system. Such oscillations will overdrive one or both amplifier chains and continuously activate
the AGC auto-shutdown circuitry. This situation will be apparent by the red fault LED being lit.
Antenna isolation is usually not a problem for in-building installations. Isolation is improved by using a
directive donor antenna and facing it away from the distribution or service antenna(s). Decoupling is
achieved by spatially separating the antennas vertically and/or horizontally. Other factors influencing
isolation include multi-path reflections, structures, other antennas, passing vehicles, personnel
proximity, etc. Contact RFS Applications Engineering for further assistance.
It is always best to measure the isolation before connecting the repeater. The most direct way to
measure the isolation is to inject a known signal into one antenna, and measure the coupled
signal at the other antenna. This should be done across the applicable bandwidth to account for
the frequency dependency of standing waves.
Diagnostics/Troubleshooting
Test Point Descriptions
• Green power LEDs indicate DC voltage is applied to the respective link.
• Yellow AGC LEDs indicate AGC is active in the respective link
• Red Fault LED indicates that a under or over current condition exists or that the AGC Shut Down
circuitry has been activated.
• Relay NC (normally closed), C (common), NO (normally open) is a summary fault relay that
changes state whenever the fault LED is lit or when the power fails. This relay is rated for up to 48
VDC at 2 Amps.
• Shut Down pin will cause the 48900 to shut down when it is connected to GND (ground). Current
draw is insignificant.
Faceplate
IMPORTANT
The 48900 is not designed for field repair. The outer cover may be removed for some
troubleshooting but under no circumstances should the covers be removed from the
internal amplifier modules, this will void the warranty.
1414
Problem: Solution:
Green power LEDs on faceplate not
lit.
Check power source and the AC fuse located in the EIC plug.
Check the DC fuse located inside the 48900 on the side of the
individual amplifier modules. Check connections to the
internal power supply.
Red LED on faceplate is lit.
First try to cycle the power then watch the AGC LEDS to make
sure the unit is not in AGC shut down. If the Fault LED is
cycling then an overdrive condition exists. See AGC
Automatic Shutdown section.
Green power LED lit and no red Fault
LED on faceplate; unit does not
appear to be working.
Check for a break in the donor or distribution networks. Also,
check to ensure the donor signal is still available to the
repeater. An obstruction could be blocking the donor base site
or the donor antenna could have become misaligned. Then,
check the integrity of the distribution network. Coaxial cable
has a minimum bending radius, if that is exceeded the inner
conductor may crack or break causing excessive reflections to
the signals.
Yellow AGC LED is lit.
AGC LEDs indicate an overdrive condition in the respective
link. Reduce the respective link gain via the Gain Adjust until
the LED goes out. Generally, the opposing link gain should be
adjusted to approximately the same setting. If the LED does
not go out, then the input signal is too strong. Sweep the input
to the respective link to identify the source of overdrive. If the
signal is not a desired signal then external filtering should be
considered to attenuate. If the signal(s) are all desired then
attenuate the base port with a 10 dB in-line attenuation pad.
Component Location
Only the power supply is field replaceable part number 31500012900
DC Fuse
Amplifier
Module
Power
Supply
1515
Maintenance, Repair and Warranty
Periodic Maintenance
There is no periodic maintenance required for the 48900. As long as the units are kept away from
extreme temperatures and moisture, they should provide long-term, carefree operation.
However, periodically check all RF connections for corrosion, strain damage, and proper tightness.
Also, periodically check the AC power connections for integrity.
Ordering and Returning Components
For technical assistance, call Radio Frequency Systems Applications Engineering at 1-800-659-
1880.
For returns, repairs, and ordering, contact Radio Frequency Systems Customer Service at 1-800-
321-4700 for a Return Authorization Number. Be prepared to provide the model number, serial
number of the unit, as well as a description of the symptoms of the problem. Send components or
units freight pre-paid with the Return Authorization Number on the outside of the package to:
Radio Frequency Systems
4100 SW Research Way
Corvallis, OR 97333
Limited Warranty
The Seller warrants that, at the time of shipment, the products manufactured by the Seller are free
from defects in material and workmanship. The Seller's obligation under this warranty is limited to
replacement or repair of such products within one year from the date of shipment. No material is
accepted for replacement or repair without written authority of the Seller. Replacement or repair is
made only after an examination at the Seller's facility shows defective material or workmanship at the
time of manufacture. All shipping charges on the returned material must be prepaid by the Buyer.
The seller is in no event liable for consequential damages, installation costs or other costs of any
nature as a result of the use of the products manufactured by the Seller, whether used in accordance
with instructions or not. The Seller is not liable for replacement of any product damaged by lightning.
This warranty is in lieu of all others, either expressed or implied. No representative is
authorized to assume for the Seller any other liability in connection with the Seller's products.