201 Target Industrial Circle
Bangor, Maine USA 04401
Phone: +1.207.947.8200
Fax: +1.207.947.3693
Customer Service (24 hour support)
+1.877.628.8353 (Canada & USA only)
+1.902.823.5100 (International)
Email: support@nautel.com
Web: www.nautel.com
The comparisons and other information provided in this document
have been prepared in good faith based on publicly available
information. The reader is encouraged to consult the respective
manufacturer's most recent published data for verification.
This manual provides information about preparing for the delivery and installation of an XR6/XR3
transmitter. This manual is intended for use by field technicians, site managers, and installation
planners.
Using this manual
Read the task list provided in Section 2, “Pre-installation tasks” on page 2-1. The task list describes
the preparations you must make prior to receiving and installing the XR6/XR3 transmitter.
Later sections of the manual provide reference information regarding physical, cooling, electrical, and
antenna requirements.
Technical support
Nautel offers technical support to customers over the Internet and by telephone. Nautel’s customer
support team will answer your questions and work with you to identify and resolve problems.
For technical support, call the Customer Support Team at 902-823-3900 or - in U.S.A. and Canada
only - call toll free at 1-877-6NAUTEL (662-8835). Or find us on the Internet at http://
www.nautel.com.
For parts and tools information, see “Parts and tools” on page 9-1 of the XR6/XR3 Pre-Installation Manual.
For accessories or spares, see “Accessories” on page 10-1 of the XR6/XR3 Pre-Installation Manual.
For standard warranty information, see “Pre-installation assistance” on page 11-1 of the
XR6/XR3 Pre-Installation Manual.
For extended warranty information, see “Pre-installation assistance” on page 11-1 of the
XR6/XR3 Pre-Installation Manual.
XR6/XR3 transmitter manuals
The XR6/XR3 documentation suite includes the following documents:
Issue 3.0 2009-07-15Page ix
XR6/XR3 Pre-installation Manual
XR6/XR3 Pre-installation Manual, XR6/XR3-PREINST. The Pre-installation Manual provides
instructions and reference information needed when planning and preparing for the installation of an
XR6/XR3 transmitter.
Nautel Site Protection Manual. The Site Protection Manual provides detailed information
about protecting your site from lightning-related hazards.
XR6/XR3 Installation Manual, XR6/XR3-INST. The Installation Manual provides instructions
and reference information needed when installing an XR6/XR3 transmitter.
XR6/XR3 Operating and Maintenance Manual, XR6/XR3-OPS-MAINT. The Operating and
Maintenance Manual provides instructions for operating, maintaining and troubleshooting
an XR6/XR3 transmitter. It also provides reference information needed when performing diagnostic
procedures.
XR6/XR3 Troubleshooting Manual, XR6/XR3-TROUBLE. The Troubleshooting Manual
provides detailed technical information about the XR6/XR3 transmitter, including electrical
schematics and mechanical drawings.
Nautel website / Online resources
The Nautel website provides useful resources to keep you up to date on your XR6/XR3.
Nautel User Group (NUG)
The website includes a special section that customers can log into in order to access the Nautel
customer newsletter, product manuals, frequently asked questions (FAQ), information sheets, and
information about field upgrades. Registration is available online and is required.
Documentation: online and printed
The website’s NUG section provides online access to all the documentation for your XR6/XR3.
Documentation is provided in Acrobat (PDF) format. You can use the documentation online or print
the sections that you need.
When using online documents:
•Click on blue text (hyperlinks) to jump to a related section, or to get additional information
(e.g., view a term’s definition).
•To search a document to find keywords, use Find in Acrobat Reader’s Edit menu.
•To quickly find a specific section, click the section in the PDF file’s
Bookmarks list.
Page xIssue 3.0 2009-07-15
XR6/XR3 Pre-installation Manual
When using printed documents:
•To find keywords, go to the Index section at the end of the manual.
•To find a specific term, go to the List of Terms section near the end of the manual.
Issue 3.0 2009-07-15Page xi
XR6/XR3 Pre-installation Manual
Page xiiIssue 3.0 2009-07-15
XR6/XR3 Pre-installation Manual
About safety
All Nautel transmitters are designed to meet the requirements of EN60215, Safety Requirements for
Radio Transmitters.
The philosophy of EN60215 is that the removal of any cover or panel that can only be opened using
a tool is a maintenance activity, and that any person performing a maintenance activity is expected to
be trained for that activity. Under EN60215, it is assumed that trained personnel will be
knowledgeable and will take precautions such as removing all power to the transmitter before
accessing its components.
Electrical hazards
To remove power from the transmitter, switch off and lock out the ac power. There are three amber
LEDs at the bottom rear of the cabinet that glow to remind anyone who has not turned off the
power that the system is live and serious danger is present.
WARNING: It is not enough to remove RF power. The power line is still
connected.
Mount the transmitter ac power disconnect switch/breaker close to the transmitter so that it can be
reached quickly in an emergency. Clearly label the disconnect switch/breaker (e.g., EMERGENCY
SWITCH
After turning off the power, always perform a measurement to confirm that the power is off before
touching anything within the transmitter. If the wrong breaker was opened, the equipment will be
live.
Use only a non-contact voltage probe or a safety voltmeter (available from vendors such as Fluke,
Ideal, and Teagam).
).
WARNING: Do not use an ordinary multimeter to check for voltage,
since it may have been left inadvertently on the AMP (A) range,
triggering a short and an arc blast that could result in severe burns
and even death.
Use a proper lockout procedure to ensure that another worker cannot accidentally reapply power
while you are performing maintenance on any part of the transmitter or site.
Issue 3.0 2009-07-15Page xiii
XR6/XR3 Pre-installation Manual
Lightning hazards
Before opening the transmitter and touching internal parts, remove and solidly ground the antenna
connection.
WARNING: It is not enough to ground the antenna terminal with the
antenna still connected. Even a small impedance in the ground strap
will result in lethal voltages during a lightning strike.
RF hazards
A serious RF hazard and very high voltages exist in the vicinity of the antenna and its networks
during normal operations.
Toxic hazards
There are devices used in this equipment containing beryllium oxide ceramic, which is non-hazardous
during normal device operation and under normal device failure conditions. These devices are
specifically identified with “(BeO)” in the Description column of the Troubleshooting Manual’s parts
list(s).
Do not cut, crush or grind devices because the resulting dust may be hazardous if inhaled.
Unserviceable devices should be disposed of as harmful waste.
Other hazards
Ensure that appropriate fire alarms and fire extinguishers are available. Extinguishers must be suitable
for use on electrical fires.
Many other site safety risks exist. It is beyond the scope of this manual to identify all the risks and
procedures.
Page xivIssue 3.0 2009-07-15
XR6/XR3 Pre-installation Manual
Safety precautions
This section provides very important information about protecting the safety of personnel and
equipment:
•Personal safety - see page xv
•Site safety - see page xvi
•Equipment safety - see page xviii
Personal safety
Training
The training of any personnel who will have physical access to the site or the transmitter is very
important. Personnel must be familiar with the transmitter, so that they can avoid physical danger,
and be aware of hazards to themselves and the equipment.
Nautel offers a number of training courses covering the basic fundamentals of RF systems and
transmitters, and the operation and maintenance of the transmitter. For more information about
available courses and schedules, go to the Nautel website at http://www.nautel.com/Training.aspx,
or ask your Nautel sales representative.
Site orientation
When you give personnel access to the transmitter site (e.g., hiring new personnel, or giving access
keys to personnel), perform a site orientation to ensure that they are familiar with the site, on-site
procedures, and on-site hazards. Cover the following topics:
•Securing the site (locking doors and fences) to prevent unauthorized access
•How and when to call for technical support or emergency assistance
•Areas of the site and pieces of equipment that are off limits
Issue 3.0 2009-07-15Page xv
XR6/XR3 Pre-installation Manual
Voltage awareness
Ensure that all personnel that are able to access areas with high voltage circuits or high field strengths
are aware of the hazards associated with high voltage. Cover the following topics:
•High voltage or high field strength areas where caution is required
•Physical risks of electric shock
•Risks for personnel with pacemakers or other medical implants
•Induced voltages in high field strength areas
•On-site risks during thunderstorms and lightning strikes
•Operation of safety interlocks (if installed)
First aid
Nautel does not offer first aid training, since the hazards associated with high voltage and RF energy
are not specific to the transmitter. However, the customer should provide first aid training to all personnel who have access to the transmitter site. First aid training should include CPR, care of burns,
artificial respiration, and defibrillation if specific equipment is available on-site.
Site safety
Controlling access
Transmitters and antennas generate and carry dangerous voltages that can be harmful or fatal. It is
very important that you control access to the site and its equipment. To secure your transmitter site,
use:
•Locking steel or security doors to prevent casual access
•A perimeter fence to keep trespassers away from the antenna system and feedline
•“No Trespassing” signs
•An alarm system
Page xviIssue 3.0 2009-07-15
XR6/XR3 Pre-installation Manual
Marking hazards
Place warning signs close to any hazardous areas or systems (e.g., the feedline or the antenna system).
Make the signs large enough that they cannot be missed. Provide signage in all languages used in the
region. These signs are intended not only for authorized personnel, but also for emergency
responders or accidental trespassers.
Qualifying site personnel
Make sure that personnel who have access to the site are qualified to work around electronics and
high voltage systems.
Ac power protection
You should take steps to protect equipment from surges (over-voltage spikes) on the ac power lines.
Surges may occur during thunderstorms, or because of malfunctions in the electrical distribution grid.
Surge suppressors and ac power conditioners can prevent serious damage to your on-site equipment,
including the transmitter.
RF protection
Transmitters and their antenna systems create intense radio frequency fields at the transmitter site,
particularly near the feedline, antenna and tower. At some sites, these fields may cause biological
effects, including the heating of body tissues. Intense fields can also create dangerous high voltages
on ungrounded, conductive surfaces and objects. At certain points where high voltage conductors
come close to grounded conductors (e.g., at feedline junctions or on the tower), dangerous electrical
arcing or flashovers can occur. It is very important that you take the following steps to prevent
damage to equipment or personnel due to RF fields:
•Use safety interlocks to de-energize transmitters if personnel open doors or panels accessing
high field areas
•Place warning signs in any locations where high fields can occur
•Train personnel about the short-term and long-term hazards of RF radiation
•Physically block access to the area around the antenna system, feedline and tower
•Ground all exposed conductive surfaces or objects in high field areas
The RF connection to the transmitter output can be a serious safety hazard. Connect a 50 Ω test load
during installation and commissioning. It is recommended that a switch be used to automatically
connect the transmitter to the antenna system without human contact with the transmitting
conductors.
Issue 3.0 2009-07-15Page xvii
XR6/XR3 Pre-installation Manual
Safety interlocks
The transmitter contains an electrical interlock, which is an external circuit that turns off the RF
output if any of its switches are opened.
Ac disconnect switch
Safe operation of the transmitter requires an ac disconnect switch. Lock the ac disconnect switch in
the disconnected (open) position during the installation process.
Equipment safety
Electrostatic protection
The transmitter’s systems are very rugged and resistant to damage. However, it is possible for damage
to occur because of high voltage electrostatic discharges during servicing. Train all service personnel
to ground themselves to bleed off any static charge before opening the transmitter or touching any
exposed components. Provide a grounding wand or known ground (e.g., a grounded metal table) that
personnel can use to discharge themselves.
Surge protection
Surge protection is recommended for your entire site. However, even if you do not use a surge
protector on the service entrance to the site, you should install a surge protector in the transmitter’s
ac power feed to prevent over-voltage from entering the transmitter.
Lightning protection
The transmitter is designed to resist lightning strike damage. However, intense or repeated strikes
could damage the transmitter. We recommend that you install lightning suppression on the antenna,
tower and feedline to reduce the effect of lightning strikes on the transmitter itself (and to protect the
rest of your site equipment and your personnel). For detailed information about lightning protection,
see the Nautel Site Preparation Manual, available from your Nautel sales agent, or online from the
Nautel website.
Physical protection
Consider physical hazards to equipment at your site, including the transmitter. Ensure that equipment
is protected from weather (e.g., rain or flooding), even during extreme weather events. Place
equipment so that it is not in the path of swinging doors or high-traffic areas. Do not allow wheeled
items like office chairs or tables with wheels in the transmitter room, as these may damage equipment
if accidentally pushed or knocked over. Do not place the transmitter under water pipes, drains, or
sprinklers. Keep any equipment that generates heat, like the transmitter, away from flammable
materials like ceiling panels, cubicle dividers, and curtains.
Page xviiiIssue 3.0 2009-07-15
XR6/XR3 Pre-installation Manual
Earthquake protection
If the transmitter site is in a region that experiences any noticeable earthquake activity, take steps to
prevent the transmitter from shifting or rocking during an earthquake. Even during minor
earthquakes, rocking or movement of the transmitter is likely to damage the feedline connection, and
could even cause a catastrophic failure of the ac power feed into the transmitter. During larger
earthquakes, the weight of the transmitter chassis could be hazardous to nearby equipment or
personnel.
Issue 3.0 2009-07-15 Page xix
XR6/XR3 Pre-installation Manual
Page xxIssue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualDescription
Section 1: Description
This section provides a basic description of the XR6/XR3 transmitter and includes the following
topics:
•Capabilities
•Options - see page 1-2
Capabilities
Power
The XR6/XR3 is rated (with 140% positive peak modulation) for an RF output of 6 kW (XR6) or 3
kW (XR3) and capable (with 120% modulation) of RF outputs up to 7.5 kW (XR6) or 3.75 kW
(XR3).
The operator can vary the power continuously or switch to preset power levels using the XR6/XR3
graphic user interface (GUI). Presets store the power level, active exciter, and power scheduler status
on a time-of-day and date basis. The operator can configure exciters on a preset for a specific
operating mode (e.g., exciter A for conventional AM, and exciter B for IBOC). The power output can
also be scheduled to correspond with authorized daytime power levels.
Modulation
The XR6/XR3 is capable of double sideband (AM) modulation. With the addition of external signal
generators, IBOC and DRM modulation can be provided to the exciter.
Duty Cycle
The XR6/XR3 will operate at nominal power with a 100% duty cycle – continuously – on an
indefinite basis.
Antenna tolerance
The XR6/XR3 will operate at rated power even with a VSWR of 1.5:1. A higher VSWR results in a
protective fallback of output power. The greater the VSWR, the greater the reduction in RF power.
(To maintain the quality of digital broadcasts, a maximum VSWR of 1.4:1 is acceptable.)
The XR6/XR3 will not fail or completely shut down, regardless of antenna or feedline failure.
Issue 3.0 2009-07-15Page 1-1
XR6/XR3 Pre-installation ManualDescription
Remote control and monitoring
The XR6/XR3 remote control and monitoring options allow you to run a multiconductor signaling
cable from the transmitter to a remote control board. This option lets you monitor all key parameters
of transmitter operation, and control common functions, such as power output and exciter selection.
Redundancy
The XR6/XR3 features redundancy in all key systems:
•RF power modules *
•Exciters
•Cooling fans
* The standard XR6/XR3 transmitter configuration contains one RF power module. A second RF power module is
optional.
Ac power
The XR6/XR3 variable power transformer can be set to use a range of input voltages and power
frequencies, as described in Section 2, “Installing the power transformer” on page 2-1of the XR6/XR3 Installation Manual.
Options
DCC
The XR6/XR3 supports Dynamic Carrier Control (DCC) as an optional module. DCC reduces the
power of the carrier when the sideband power drops below a threshold (that is, when there are
periods of silence in the program content). This reduces overall power consumption.
IBOC
The XR6/XR3 supports IBOC digital radio as a modulation option. The external IBOC signal
source provides a signal to the XR6/XR3 exciter.
DRM
The XR6/XR3 supports Digital Radio Mondiale (DRM) radio as a modulation option. The external
DRM signal source provides a signal to the XR6/XR3 exciter.
Page 1-2Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualDescription
NxLink
An optional NxLink module provides an Ethernet interface between the XR6/XR3 and a LAN (local
area network). This interface allows remote control and monitoring of the XR6/XR3 from a
computer .
Safety interlocks
Optional safety interlocks prevent unsafe access to the transmitter until the ac power is removed.
This section provides a list of tasks that you must perform prior to delivery and installation of the
XR6/XR3 transmitter.
WARNING: FAILURE TO COMPLY WITH RECOMMENDATIONS MAY VOID
YOUR MANUFACTURER’S WARRANTY. FOR MORE INFORMATION, REVIEW
YOUR WARRANTY DOCUMENTS.
Preparing for installation
To prepare for installation of an XR6/XR3 transmitter, perform the following tasks:
1. Ensure that the correct transmitter configuration is ordered. Check the ac power
requirements, preset frequency, IBOC option, and other options.
2. Select a location for the transmitter in the transmitter room. Determine whether additional
heating, ventilating or cooling capacity is needed at the site. Identify any special requirements
regarding air flow around the cabinet (for example, ducting hot air away from the cabinet, or
bringing in external cooling air).
3. If this is an upgrade or replacement transmitter (that is, if the site is already set up for a
transmitter), go to Step 7. (If you are upgrading a site, verify the feedline, the lightning
protection systems, and the ac power service. Refer to the Nautel Site Protection Manual.)
4. Install ac power service into the planned location of the transmitter, and select a location for
an ac power disconnect near the transmitter location. For detailed information, see
“Electrical power” on page 5-1.
Be aware of lightning protection issues when installing ac power. Lightning protection is
essential to protect both personnel and equipment at your site. Refer to the Nautel Site
Protection Manual.
5. Install lightning protection on the antenna tower. Refer to the Nautel Site Protection Manual.
6. Place a work area with a clear table surface near the transmitter location. Provide electrostatic
protection measures in the work area.
7. Order any accessories or optional equipment that you may need.
8. Terminate the transmitter end of the RF feedline with the appropriate mating connector.
Unless otherwise specified in contract documents, the transmitter will accept a 1-5/8 inch
EIA flange connector.
9. If the transmitter will be used to broadcast IBOC, perform a full impedance sweep of the
antenna system. See “Antenna system” on page 8-3.
10. Arrange manpower or lifting equipment to move and assemble the transmitter. You may
want to use a forklift to move either the transmitter or its power transformer into place for
installation.
11. Implement a safety interlock, if required.
12. If you are going to use an external RF drive, ensure that the drive meets required
specifications.
13. If you are going to use an external frequency reference, ensure that the reference source
meets required specifications.
14. Prepare to integrate the XR6/XR3 transmitter into your station control circuitry, if required.
15. Train your station technicians and operators on the use and maintenance of the XR6/XR3
transmitter.
Selecting a location for the transmitter
To ensure that the desired location for the XR6/XR3 transmitter is suitable, perform the following
tasks:
1. Ensure that the floor area where the transmitter will be located is able to support the weight
of the transmitter system.
The total weight of the assembled transmitter, once installed, is 213 kg (469 lbs).
2. Measure the space to ensure that the transmitter will fit.
See Section 3, “Physical requirements” on page 3-1 for transmitter dimensions.
3. Ensure that transmitter room doors and the pathway of access from the receiving dock or
building exterior to the installation location are large enough to accommodate the
transmitter.
When installing an antenna feedline for the XR6/XR3 transmitter, perform the following tasks:
1. Ensure that the RF feedline that will connect the transmitter and the antenna system has a
suitably rated coaxial cable.
2. Connect the shield of the antenna feedline coaxial cable directly to the station reference
ground where it enters the building. For more information about the station reference
ground, see “Station reference ground” on page 5-4.
3. Install lightning protection devices. For more information about lightning protection, refer
to the Nautel Site Protection Manual.
4. Pass the center conductor and the shield of the feedline cable through a ferrite toroid that is
positioned between the shield ground at the building entrance and the shield termination at
the transmitter. Install the ferrite toroid prior to installing flanges on the feedline cable.
•The ferrite toroid included in the ancillary kit, provided by Nautel with the transmitter,
can be used for coax cables with diameters up to 1 5/8 inches (1.625 in.). For larger
diameters,contact Nautel support for recommendations (see page 11-3), or consult
additional, outside suppliers.
This section provides physical specifications for the XR6/XR3 transmitter and its components, and
lists physical site requirements. This section includes the following topics:
•Clearances
•XR6/XR3 transmitter dimensions - see page 3-2
•Weights - see page 3-5
Clearances
Required minimum clearances are 1.2 m (4.0 feet) at the front of the transmitter, and 1.8 m (6.0 feet)
at the rear of the transmitter. (The clearance at the rear of the transmitter is required to allow
installation of the power transformer. Less clearance may be acceptable if special arrangements are
made to install the transformer.) No clearance is required on either side of the transmitter.
Check the clearance to ensure that you will be able to open all doors and access panels. The front
control panel is hinged on the left (when looking at the front of the transmitter).
Also consider access to the rear of the transmitter during transformer installation and servicing, and
access to the front of the transmitter during power module replacement. You must allow space to
open the front panel and slide out any of the power modules. These modules slide straight in and out
of the shelf unit in the front of the transmitter.
Internal fans pull cooling air through air filters in the upper rear panel. The cooling air exhausts as a
low velocity stream through openings on top of the transmitter.
This section provides information about heating and cooling requirements for the XR6/XR3
transmitter site. Topics in this section include:
•Air flow in the transmitter
•Cooling - see page 4-2
•Heating - see page 4-3
Air flow in the transmitter
The XR6/XR3 uses redundant cooling fans and hot-air convection to ensure effective cooling. Cool
air is drawn in through a filter in the lower portion of the back of the transmitter. Air circulates into
the base of the transmitter, and is then pushed up through the front rack of the transmitter by a set of
fans. Warm air exits the transmitter through the grill or duct at the top of the transmitter.
Figure 4.1: Air flow in the XR6/XR3 transmitter cabinet with back panel filter installed
Do not allow the transmitter room ambient air temperature to exceed 50°C (122°F) at sea level.
Cooler temperatures are recommended in order to improve the reliability of the transmitter.
•De-rate the ambient temperature 3ºC (5.4°F) per 500 m – or 2ºC (3.6°F) per 1,000
feet – above sea level.
Example: At 1600 m (1 mile) above sea level, maximum ambient temperature should not
exceed 40.4ºC (104.7°F).
Ensure that hot air from the transmitter is not drawn back into the transmitter’s cool air intake.
To determine the number of British thermal units (Btu) being generated per hour as waste heat,
multiply the average RF output power (in watts) by 0.19 (the heat factor at rated power) and then
multiply the product by 3.413.
Closed loop or forced air cooling systems
Closed loop or forced air cooling systems can be used, so long as the air is well filtered to prevent
dust and insects from entering the transmitter, and so long as a minimum of 200 cubic feet per
minute (CFM) at 0.5 pounds per square inch (PSI) is supplied to the intake duct.
Heating
The transmitter room must contain a heating system that will ensure the ambient air temperature
does not drop below 0°C (32°F).
This section describes electrical power and electrical protection requirements associated with the
XR6/XR3 transmitter. This section includes the following topics:
•Electrical power
•Station reference ground - see page 5-4
CAUTION: Technical pre-commissioning activities described in this section
require technical decisions and the customization of electrical circuits. Do
not attempt to perform these activities unless you are a certified
electrician.
Refer to the Nautel Site Protection Manual for information about requirements associated with lightning
protection.
Electrical power
The transmitter is preconfigured to operate from a 50/60 Hz, 3-phase (3-wire plus ground, Wye or
closed delta)or 1-phase (2-wire plus ground) ac power source. You select the number of phases and
specific voltage range when you order the transmitter.
Nominal voltage (minimum and maximum)
The primary winding of the main ac power transformer contains taps to accommodate voltages that
differ from the ideal voltage of the power source. These taps provide increments and are selected
during installation to provide the nominal voltage for the transmitter.
The high voltage transformer comes with the following standard taps:
The ac power source nominal voltage must be stable to within plus or minus 10% under all loading
conditions. The transmitter contains circuitry that maintains the RF output at the preset carrier level
for voltage variations within the specified range, provided the correct transformer tap is chosen.
Table 5.2: Voltage Stability
Ac Power
Source
3-phaseLV188263
1-phase-180286
TransformerVoltage Range
MinimumMaximum
HV325459
Power consumption
When operating at 6 kW (XR6) or 3 kW (XR3) with 100% modulation by a continuous sine wave,
power consumption is approximately 10.8 kW (XR6) or 5.4 kW (XR3). When operating at 6 kW
(XR6) or 3 kW (XR3) with no modulation, power consumption is 7.2 kW (XR6) or 3.6 kW (XR3).
Power consumption for a specific station will depend on the programming format and the level of
audio processing. Nautel recommends the ac power source have a 25% over-capacity to ensure
adequate regulation.
Ac power switch
Install an external ac power disconnect between the ac power source and the transmitter. (Nautel can
provide a suitable ac power disconnect, if required.) For safety, place the ac disconnect close to the
transmitter and label it
TRANSMITTER EMERGENCY ON/OFF SWITCH.
Ac transient power protection
Protect all conductors from the ac power source by connecting bi-directional surge protection
devices between each conductor and the station reference ground. In addition, pass all the
conductors, as a group, through a ferrite toroid. Install a ferrite toroid on the ac feed between the
transmitter and the bi-directional surge protector.)
•The ferrite toroid included in the ancillary kit, provided by Nautel with the transmitter, can
be used for most ac supply cables. For larger diameters, contact Nautel support for recommendations (see page 11-3), or consult additional, outside suppliers.
A surge protector panel containing suitably rated varistors is available from Nautel. Install the surge
protector panel close to the station reference ground, and as close as possible to the ac service
entrance.
The ac power source usually has the lowest impedance path to ground during a lightning strike and
normally carries most of the lightning-induced current away from the transmitter site. When lightning
hits the power source (for example, striking a transmission line near the transmitter site), a significant
induced current may flow towards the transmitter. The goal of lightning protection is to route the
current around the transmitter to the best available ground.
For detailed information about surge protectors and lightning protection, refer to the Nautel Site
Protection Manual.
Recommended configuration for three-phase ac power source. Use a 4-wire Wye (star)
configuration, with the three phases balanced to ground.
CAUTION:
For three-phase applications do NOT use open delta ac power sources that
use two identical transformers. These systems are susceptible to third
harmonic distortion and line transients, and may cause peak voltages to
exceed the line voltage. This can cause increased power supply noise or
even component failure (for example, rectifier failure).
Wiring
Table 5.3 on page 5-4 shows the wiring recommendations for each ac voltage, and identifies the wire
gauges that are specified for worst case conditions. Smaller gauges may be used when actual
conditions related to transmitter power and wiring allow it. A certified electrician should be consulted
to ensure that all wiring meets local electrical code requirements.
CAUTION:
Table 5.3 on page 5-4 is based on recommendations by the Canadian
666208 V ac, 3-ph32 (XR6), 16 (XR3)
688240 V ac, 3-ph27 (XR6), 13.5 (XR3)
101010380 V ac, 3-ph17 (XR6), 8.5 A (XR3)
444220 V ac, 1-ph59 (XR6), 29.5 (XR3)
VoltageAmps/Phase
Station reference ground
Install a station reference ground that provides a continuous, low impedance path to the earth.
If a surge protector is not being used, connect the transmitter cabinet's designated safety ground
point, the shield of the coaxial feedline, and the ground connection of the power source directly to
the station reference ground using a copper strap that is at least 10 cm (4 in.) wide. Ensure that the
site’s ac service entrance ground is directly connected to the station reference ground outside the
transmitter building.
If a surge protector is being used, connect the transmitter cabinet's designated safety ground point,
the shield of the coaxial feedline, and the ground connection of the power source directly to the surge
protector, using a 10 cm (4 in.) copper strap. Connect the surge protector to the station reference
ground using a copper strap that is at least 10 cm (4 inches) wide.
Ac power can enter the transmitter cabinet through the right rear side of the top panel (see Figure 3.2
on page 3-3)or the rear side of the bottom panel (see Figure 3.3 on page 3-4).
Ensure that the transmitter site’s grounding rods are adequate. For more information about electrical
grounding protection, see the Nautel Site Protection Manual.
Page 5-4Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualControl and monitoring
Section 6: Control and monitoring
This section describes control and monitoring of the XR6/XR3 transmitter. This section includes the
following topics:
•Controls
•Alarm definitions
•Remote control circuits and alarms - see page 6-7
•Remote performance monitoring - see page 6-12
•LAN interface (NxLink) - see page 6-13
Controls
The XR6/XR3’s graphic user interface (GUI) lets you control a number of transmitter functions and
set parameters and schedules. (For detailed information about the GUI, refer to the XR6/XR3 Operating and Maintenance Manual.) In addition, you can control the on/off status, the active (A/B)
exciter, the preset RF power level, the power level adjustment, and system alarm reset remotely by
means of a conventional remote control interface (see “Remote control circuits and alarms” on
page 6-7or a LAN, using the optional NxLink module (see“LAN interface (NxLink)” on page 6-13).
Alarm definitions
This section describes the alarms that may occur, and what they indicate.
DC voltage supply faults
Fan P/S fault
The 48 V power supply used for the fans is monitored. A fault will be reported if the voltage varies by
more than ± 10%.
RF drive P/S fault
The 62 V power supply used for the RF drive is monitored. A fault will be reported if the voltage
varies by more than ± 10%.
Issue 3.0 2009-07-15Page 6-1
XR6/XR3 Pre-installation ManualControl and monitoring
LVPS fault
The +24 V, +15 V, -15 V and +5 V power supplies are monitored. A fault will be reported if the
voltage varies by more than ± 10%.
•One or more of these faults will result in only one LVPS Fault message on the Status screen,
though each one would be logged separately in the Event Log.
High B+ voltage
A fault is reported when the B+ voltage goes above 380 V. No other action will be performed
automatically.
Low B+ voltage
For three-phase XR6 transmitters, there are three B+ voltage levels that will be automatically selected
to provide optimum performance: 315 V, 190 V and 115 V. For three-phase XR3 transmitters, there
are two B+ voltage levels: 220 V and 115 V. For single-phase XR6 transmitters, there are four B+
voltage levels: 315 V, 196 V, 115 V and 69 V. For single-phase XR3 transmitters, there are four
B+voltage levels: 220 V, 196 V, 115 V and 69 V.
This alarm is triggered when the B+ voltage falls below the factory-set alarm threshold. The alarm
threshold is factory calibrated to be approximately 250 V, 150 V or 91 V - for three-phase XR6
transmitters - to correspond to the B+ voltage level currently in use. For three-phase XR3
transmitters, the alarm threshold voltage is factory calibrated to be approximately 174 V or 91 V. For
single-phase XR6 transmitters, the alarm threshold voltage is factory calibrated to be approximately
250 V, 155 V, 91 V or 55 V. For single-phase XR3 transmitters, the alarm threshold voltage is factory
calibrated to be approximately 175 V, 155 V, 91 V or 55 V.
Besides being noted on the transmitter’s GUI Status screen, and by the alarms, this alarm also causes
the following:
•a shutback
•the softstart relays to open
•the fans to turn off
Recovery from this alarm is automatic when the B+ voltage rises above the factory-set alarm
threshold, which is factory-calibrated to 265 V, 160 V and 97 V - for three-phase XR6 transmitters depending on which B+ voltage is selected (see “Low B+ voltage” on page 6-2). For three-phase
XR3 transmitters, the factory-calibrated threshold is 185 V or 97 V. For single-phase XR6
transmitters, the factory calibrated threshold is 265 V, 165 V, 97 V or 59 V. For single-phase XR3
transmitters, the factory calibrated threshold is 185 V, 165 V, 97 V or 59 V. The recovery process is
the same as the power on process.
Page 6-2Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualControl and monitoring
Output network faults
High DC current
This alarm is triggered when the dc current goes above approximately 41 A (XR6) or 21 A (XR3).
High RF current
This alarm is triggered when the RF current exceeds the factory-set alarm threshold.
High VSWR shutback
This alarm is triggered when the reflected power exceeds the factory-set alarm threshold approximately 480 W (XR3) or 960 W (XR6).
Total power limit
This fault is triggered when the product of the B+ (dc) voltage and the dc current is greater than
approximately 15 kVA (XR6) or 7.5 kVA (XR3).
•This fault causes an immediate cutback, but not a shutback.
Exciter faults
Mod driver fault A
This fault is reported to the microcontroller only if exciter A is selected. If the exciter transfer
function is set to auto, then the microcontroller will attempt a changeover to exciter B. If it cannot, or
if the exciter transfer function is set to manual, then this fault will cause a shutback.
Mod driver fault B
This fault is reported to the microcontroller only if exciter B is selected. If the exciter transfer
function is set to auto, then the microcontroller will attempt a changeover to exciter A. If it cannot, or
if the exciter transfer function is set to manual, then this fault will cause a shutback.
Auto changeover
This event is caused by a fault in the active exciter when the exciter transfer function is enabled (set to
auto). These faults cause exciter changeovers: Mod Driver Fail A/B, RF Driver Fail, or PDM Drive
Fail.
This fault causes the
it is manually cleared. No further auto changeovers are possible until the alarm is cleared.
•The Auto changeover alarm can be cleared remotely by re-selecting the active exciter, or
locally by using the transmitter’s GUI Preset screen.
Changeover LED on the transmitter’s front panel to light. It will remain lit until
Issue 3.0 2009-07-15Page 6-3
XR6/XR3 Pre-installation ManualControl and monitoring
RF driver fault
This fault indicates a problem with the RF drive on the current exciter. If the exciter transfer function
is set to auto, then the microcontroller will attempt a changeover to the other exciter. If it cannot, or if
the exciter transfer function is set to manual, then this fault will cause a shutback.
PDM drive fault
This fault indicates that the PDM drive has stopped functioning. If the exciter transfer function is set
to auto, then the microcontroller will attempt a changeover to the other exciter. If it cannot, or if the
exciter transfer function is set to manual, then this fault will cause a shutback.
Cutbacks
Cutback level (1-8)
If three shutbacks occur within five seconds, the transmitter will enter a power reduction mode called
a cutback.
There are eight levels of cutbacks, the last being a reduction to almost no forward power.
At any given cutback level, there is a predefined time limit that must expire before the cutback level
returns to the previous level (e.g., level three back to level two). If there are no further cutbacks, this
process continues until Level 0 (normal) is reached.
The cutback recovery process can be overridden by adjusting the power (up or down), or by initiating
a reset - by pressing Reset on the transmitter’s GUI Status screen or by remote application.
Remote interface faults
Ext. interlock open
The external interlock input is wired to the remote interface PWB by the end user, and triggered by
the conditions that they set (e.g., opening the door to the transmitter room). A triggered interlock
may indicate a safety issue.
Ext. PDM inhibit
An EXTERNAL PDM INHIBIT alarm indicates that an external PDM inhibit command is present. The
external PDM Inhibit is wired to the remote interface PWB.
Int. serial fault
This alarm indicates that there is no communication with the remote interface PWB.
The control/display PWB requests updates from the remote interface PWB every 200 ms. This alarm
is triggered when a control/monitor PWB’s request for information is not acknowledged by the
remote interface PWB within two seconds.
Page 6-4Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualControl and monitoring
Mod. protection
This fault is reported from the remote interface PWB. The fault indicates that excessive low
frequency modulation has triggered the transmitter’s protection circuit.
Softstart faults
Softstart active
The softstart relays are initially open for 1.6 seconds when the transmitter is first powered on. The
software should close the relays after 1.6 seconds and clear this alarm.
While active, this alarm causes a shutback and inhibits the RF drive and fan power supplies.
Softstart overtemp
The software keeps track of the calculated temperature of the softstart resistors and triggers this fault
if that value is greater than 150°C (302°F).While this fault is on, RF power will not be available.
The temperature is assumed to rise 20°C (68°F) for each cold start, and 10°C (50°F) for each warm
start. The calculated temperature falls exponentially between starts.
The transmitter’s GUI Status screen will show the current, calculated temperature, if it is above
150°C (302°F).
CAUTION:
Performing a warm or cold start while this fault is active is strongly discouraged.
RF Power module faults
PM Fault A or B*
•A fault is being reported by power module A or B.
Note: A second RF power module is optional with an XR6 or XR3 transmitter.
*
Other faults
Low backup battery
This fault indicates that the backup battery voltage has fallen below an acceptable level. The fault may
be caused by weak batteries, or a fault in the detection or alarm circuitry on the control/monitor
PWB.
Issue 3.0 2009-07-15Page 6-5
XR6/XR3 Pre-installation ManualControl and monitoring
The backup battery should be replaced while ac power is ON. If the ac power faults, without adequate
backup battery power, then the log files will be lost.
CAUTION:
Do not wait for an extended period to replace the batteries. The control/monitor
PWB’s microcontroller may not retain its settings if ac power is turned off when
the backup battery voltage is too low.
Page 6-6Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualControl and monitoring
Remote control circuits and alarms
You can control the active (A/B) exciter, the on/off status of the RF power stage, the preset RF
power level, the power level adjustment, and system alarm reset remotely. The remote interface PWB
contains a selection circuit that lets you select internal (single ended input) or external (differential
input) input for all controlled functions.
The external control circuits interface with the transmitter through opto couplers on the remote
interface PWB. The opto couplers buffer and isolate the external circuits and prevent any unwanted
transients from affecting transmitter operation while remote control is selected at the transmitter.
The switching circuits for the remotely controlled functions must be the equivalent of a normally
open (momentary) switch. The switches must be configured to operate as a single-ended input using
the transmitter's 24 V dc as the source, or as a differential input using an external dc power supply (24
- 30 V). Each control function has negative inputs on the remote interface PWB. The positive
external
Option 1 - Single Ended Input (Internal V dc). When you use the transmitter's 24 V as the
current source for a control function's opto coupler, configure the circuit on the remote interface
PWB for a single ended input. The SINGLE/DIFF 3-pin header (E19) must have its 2-socket shunt
post connected between pins 2 and 3 to configure the circuit.
+24 V IN input (TB1-3) is used by all control functions.
Figure 6.1: Single-ended Input Selected
+24 V IN
(TB1-3)
S1830900 V1
18
+24V
3
E19
12
SINGLE
REMOTE SELECTION CIRCUITRY
CONFIGURED FOR INTERNAL
REMOTE
INTERFACE
PWB
DC VOLTS
A negative logic (active state is a current-sink-to-ground) command must be applied to the control's
negative (-) input. To avoid a ground loop, obtain the ground from TB1-18.
Issue 3.0 2009-07-15Page 6-7
XR6/XR3 Pre-installation ManualControl and monitoring
Option 2 - Differential Input (External V dc). When you use an external dc voltage (24 V to
30 V) as the current source for a control function's opto coupler, configure the control function's
external switching circuit and the remote interface PWB’s selection circuit for a differential input. The
SINGLE/DIFF 3-pin header (E19) must have its 2-socket shunt post connected between pins 1 and 2
to configure the circuit.
Figure 6.2: Differential Input Selected
EXTERNAL DC
PWR SUPPLY
(+24V TO +30V)
S1830901 V2
+24 V IN
(TB1-3)
18
+24V
3
E19
12
DIFF
REMOTE SELECTION CIRCUITRY
CONFIGURED FOR EXTERNAL
REMOTE
INTERFACE
PWB
DC VOLTS
The normally open/momentarily closed switch should be located between the dc voltage's negative
output and the remote control circuit’s negative (-) input.
Inputs
This section describes the remote inputs to the system. These inputs are only accepted by the system
if the remote/local status is set to remote, unless otherwise noted. That setting can only be made by a
local user.
Inputs are toggled between states by an active pulse unless otherwise noted. To ensure proper
operation, the duration of the active pulse should be a minimum of 250 ms.
Note: The external PDM inhibit input is intended to be used in conjunction with
antenna switching circuitry, to ensure minimal RF output current is flowing during
the opening/closing of contacts in the transmitter's RF feed cable. An active
inhibit
condition must be applied, to inhibit the RF output, prior to contact
PDM
opening. The active condition must be maintained until contact closure has
occurred, and an appropriate impedance has been connected to the transmitter's
RF output. The RF output will instantly be restored to its original level when the
active condition is removed.
Page 6-8Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualControl and monitoring
•TB2-6 (-): PDM INHB terminal. Continuous active signal inhibits the PDM by causing a shutback. This also works when the remote/local status is set to local.
•TB1-1 and TB1-2: EXT INTLK terminals. A short circuit between the pins for normal operating status, an open between these pins causes a shutback. This also works when the remote/
local status is set to local.
•TB1-4 (-): RF OFF terminal. Same as pressing the RF Off button on the front panel. Provide
an active pulse to activate.
•TB1-6 (-): RF ON terminal. Same as pressing the RF On button on the front panel. Tells the
system to provide RF power if possible. Provide an active pulse to activate.
•TB1-8 (-):
•J3-23 (-): IBOC Input Select A input. Sets IBOC/Analog for Exciter A. Continuous active signal selects IBOC input, otherwise analog input is selected.
•J3-25 (-): IBOC Input Select B input. Sets IBOC/Analog for Exciter B. Continuous active signal selects IBOC input, otherwise analog input is selected.
•J2-10 (-): Preset Scheduler (Auto/Man) input. Enables or disables the Automatic Preset (formerly power level) changes. Provide an active pulse to toggle between Auto or Manual
modes.
The following inputs will only take effect when the Preset Scheduler Mode is set to Manual.
•J2-12 (-): Preset 1 input. Selects RF power preset 1 of 6. Provide an active pulse to activate.
•J2-14 (-): Preset 2 input. Selects RF power preset 2 of 6. Provide an active pulse to activate.
•J2-16 (-): Preset 3 input. Selects RF power preset 3 of 6. Provide an active pulse to activate.
•J2-18 (-): Preset 4 input. Selects RF power preset 4 of 6. Provide an active pulse to activate.
RESET terminal. Causes a system reset. Provide an active pulse to activate.
•J2-20 (-): Preset 5 input. Selects RF power preset 5 of 6. Provide an active pulse to activate.
•J2-22 (-): Preset 6 input. Selects RF power preset 5 of 6. Provide an active pulse to activate.
Note: A minimum one second interval between commands is required for the
following two exciter selection commands.
Issue 3.0 2009-07-15Page 6-9
XR6/XR3 Pre-installation ManualControl and monitoring
•TB1-14 (-): EXCITER A terminal. Causes a changeover to select exciter A as the main exciter.
Setting is saved in current preset. Provide an active pulse to select this exciter.
•TB1-16 (-): EXCITER B terminal. Causes a changeover to select exciter B as the main exciter.
Setting is saved in current preset. Provide an active pulse to select this exciter.
•TB1-10 (-): POWER INCREASE terminal. Increases the power level of the current preset.
Send an active pulse to increase the power slightly, or send a signal of greater duration to
continue increasing the power.
•TB1-12 (-): POWER DECREASE terminal. Decreases the power level of the current preset.
Send an active pulse to decrease the power slightly, or send a signal of greater duration to
continue decreasing the power.
Remote status and alarm indications
Outputs that indicate the status of operator controlled circuits are available on connectors J2 and J3
on the remote interface PWB. A switching device for each alarm output provides current-sink-toground when a logic true condition exists.
The switching circuit provides an open collector for a logic false condition and has no influence on
the external monitoring circuit.
The following outputs are available:
Note: All outputs are active low.
•J3-18: Exciter Changeover. See “Auto changeover” on page 6-3.
•J2-24: Preset Scheduler On Status.
•J3-21: Auto Exciter Status. Indicates if the current preset allows auto exciter changeover in the
event of failures. (Set from the GUI only.)
•J3-20: Memory Battery Alarm. See “Low backup battery” on page 6-5.
•J3-19: RF Overcurrent Alarm. See “High RF current” on page 6-3.
•J2-23: Exciter B Status. Indicates which exciter is presently active.
•J3-15: LV P S Fail. See “LVPS fault” on page 6-2.
•J3-14: Exciter Fail.
Page 6-10Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualControl and monitoring
•J3-13: Pwr Mod Fail. One or more power modules has a fault.
•J3-12: Low B+. See “Low B+ voltage” on page 6-2.
•J3-11: High VSWR. See “High VSWR shutback” on page 6-3.
•J3-17: Cutback. See “Cutback level (1-8)” on page 6-4.
•J3-16: Shutback. Indicates that a shutback is currently active.
•J3-3: RF On Status. Indicates that the RF On LED is active, showing the operator’s request
for RF power.
•J3-(5,6,7,8,9,10): Preset (1-6) Status. Indicates which preset is currently active.
•J3-4: Remote Status. Indicates whether or not the system is in Remote or Local control mode.
Changes can only be made remotely if the transmitter is set to Remote mode. The local
user’s control of transmitter operation is limited, unless the transmitter is set to Local mode.
Issue 3.0 2009-07-15Page 6-11
XR6/XR3 Pre-installation ManualControl and monitoring
Remote performance monitoring
The transmitter provides outputs that let you monitor RF performance. They include dc voltages that
represent the forward power level, the reflected power level, the B+ voltage and the dc current. In
addition, a true RF sample of the RF output voltage waveform is available for external monitoring.
These outputs are provided on the remote interface PWB.
Analog samples
Sample voltages, in the range of 0 to 4 V are provided for the following system parameters:
•J2-1: Fwd Power
•J2-3: Refld Power
•J2-5: B+ Voltage
•J2-7: Dc Current
•J8: RF Monitor
Forward power level. A buffered dc voltage that reports the forward power level on J2-1. This
voltage is a pure square law function and will be 3.9 ± 0.5 V when the forward power is 6.5 kW (XR6)
or 2.8 ± 0.5 V when the forward power is 3.3 kW (XR3). The monitoring circuit’s impedance must be
greater than 1,000 ohms.
Reflected power level. A buffered dc voltage that reports the reflected power level on J2-3. This
voltage is a pure square law function and will be 3.9 ± 0.5 V when the reflected power is 960 W
(XR6) or 2.8 ± 0.5 V when the reflected power is 480 W (XR3). The monitoring circuit’s impedance
must be greater than 1,000 ohms.
B+ volts. A buffered dc voltage on J2-5 that is directly proportional to the dc voltage from the main
dc power supply. This voltage will be 3.0 V when the dc voltage being applied to the RF stage is
312 V. The monitoring circuit impedance must be greater than 1,000 ohms.
Dc Current. A buffered dc voltage on J2-7 that reports the dc current level of the main B+ power
supply. The output is 3.0 ± 0.5 V with a dc current of 40 A.
Page 6-12Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualControl and monitoring
RF monitor sample. A true sample of the RF output voltage waveform is available through the J8
BNC connector (RF MONITOR) on the remote interface PWB. The RF monitor output is intended
to be applied to a station modulation monitor with a 50 Ω input impedance. It may also be monitored
by an oscilloscope during maintenance procedures. The RF monitor output can be set to provide
1.0 V rms or 5.0 V rms for each preset power level, provided they are preset to a level that is between
600 W and 6 kW (XR6) or between 300 W and 3 kW (XR3).
Note: Some older modulation monitors may not accept a 1 V input.
Note: The output level range is determined by the setting of the BYPASS/GAIN
switch. When the switch is set BYPASS, the RF monitor sample voltage is a
nominal 1 V rms. When the switch is set to GAIN, the RF monitor sample voltage
increases to a nominal 5 V rms. The rms output level is adjusted from the GUI.
Setting the level higher than the limit determined by the BYPASS/GAIN switch
[1 V rms or 5 V rms (carrier)] will cause distortion in the waveform, and may
prevent accurate measurement of the modulation depth.
LAN interface (NxLink)
A serial port is available on 9-pin D-sub connector J12 of the XR6/XR3’s remote interface PWB.
This port allows you to remotely control and interrogate the XR6/XR3’s operational status. If the
NxLink Ethernet interface module option is installed and you wish to use it as the remote interface,
connector J12 is linked to Port 1 of the NxLink module. Refer to the NxLink Technical Instructions Manual for further details on the NxLink module.
Issue 3.0 2009-07-15Page 6-13
XR6/XR3 Pre-installation ManualControl and monitoring
This section describes other considerations regarding the XR6/XR3 transmitter.
•External RF drive source
•External 10 MHz frequency reference - see page 7-2
External RF drive source
You can apply an externally generated RF drive (carrier frequency only) to the remote interface
board’s digital EXT RF IN BNC connector (J6). This replaces the internal carrier frequency oscillator
for one or both exciters (A/B).
Note: There is only one external RF drive input. If you use it for both exciters,
duplicate the RF drive source (main/standby), and incorporate an automatic
changeover circuit to select the standby source if the main source fails.
The external RF drive must:
•be the carrier frequency (ƒc), within ± 5 Hz or 5 parts per million (ppm), whichever is
greater, when it is not being modulated.
•have a peak-to-peak amplitude of between 5.0 V and 12 V (sine wave or square wave).
•be spectrally pure when it is not being modulated.
Note: Any signal connected to the EXT RF IN input may affect the transmitter’s RF
output. To comply with regulatory limits on emissions, ensure that the RF drive
source is acceptable.
1. If the RF drive for one or both exciters is to be applied from an external source, connect its
wiring as follows:
– Route RF drive coaxial cable through a cable entry hole in the cabinet and through the
ferrite toroid, to the vicinity of the remote interface PWB.
– Cut the RF drive coaxial cable to length, terminate it with a coaxial BNC connector and
connect it to the remote interface PWB’s EXT RF connector (J6).
2. Configure either (or both) exciter RF synthesizer(s) to operate on Ext RF drive by setting the
E4 jumper(s) to 1-2.
External 10 MHz frequency reference
You can apply an externally generated 10 MHz signal (such as a GPS clock signal) for use as the
reference frequency for the RF drive (carrier frequency) to the 10 MHz REFERENCE INPUT BNC
connector J2 on each RF synthesizer PWB.
1. The external 10 MHz frequency reference (one for each RF synthesizer PWB) must:
– remain stable at 10 MHz within ± 20 Hz
– have a peak-to-peak amplitude of between 2.2 V and 8.0 V (sine wave or square wave)
– be spectrally pure, since spurs may pass through to the transmitter output.
2. Configure each RF synthesizer PWB by setting E2 to 1-2 and E1 to 1-2.
This section describes requirements associated with the antenna and RF cabling to be used with the
XR6/XR3 transmitter.
Antenna considerations include the following:
•Antenna feed cable
•Antenna system - see page 8-3
For detailed information about protecting the transmitter system from antenna lightning strikes, see
the Nautel Site Protection Manual.
Antenna feed cable
Maximum voltage
The maximum voltage at the transmitter’s connection to a 50 Ω load is 2,617 V peak, when operating
at 6 kW (1,851 V peak at 3 kW), with 125% modulation.
High voltage feed throughs
Be very careful whenever a high voltage RF conductor passes through a wall or bulkhead. Gas
insulation flashovers can occur in poor installations. Ensure that this part of your installation is
installed by professionals experienced with high-power radio frequency circuits.
Insulator flashover. Surface flashovers along an insulator occur when there is an electrical
breakdown in the gas (normally air) at its surface. The mechanism that triggers a flashover depends
on the insulation surface conditions. Gas breakdown flashover occurs when one or more of the
following conditions are met:
•The voltage field at the insulator surface or at an adjacent electrode reaches the critical breakdown level for the gas.
•The electrode or insulator interface is poor or dirty, resulting in a three material junction.
This creates excessive high voltage stress on the air insulator, causing a gas breakdown flashover.
•Moisture damage on the insulator surface creates regions of high voltage that can cause a gas
breakdown flashover.
Three-material junctions: A frequent cause of breakdowns at an insulator surface is the junction
of three materials: a metal conductor, a solid insulator, and a gas insulator. The insulators form a
capacitive RF divider between the metal conductor and the grounded periphery. Since the dielectric
constant of the solid is higher than the gas (air), the high voltage stress is concentrated on the air.
It is very important to minimize the junction's stress gradient and to avoid triple junctions wherever
possible.
WARNING: FAILURE TO PROVIDE CORRECT STRESS CONTROL AT HIGH RF
VOLTAGE CONDUCTOR/INSULATOR JUNCTIONS CAN CAUSE INSULATOR
BREAKDOWNS OR EVEN FIRES.
Bowl type bushings. Use bowl type bushing insulators to increase the surface tracking distance
from the central conductor to the grounded periphery or wall.
Insulator Breakdown/Damage. An insulator can be damaged during gas breakdown flashovers.
When current flows across the surface of an insulator, especially when it is coated with a conductive
contaminant that is slightly damp, carbon tracks can form. Once this occurs, the track provides a
conductive path and reduces the effectiveness of the insulator.
Pitting and erosion of the insulator may also occur. To reduce the possibility of tracking damage,
clean all insulator surfaces periodically, and use stress control techniques at the conductor/insulator
junction.
Other causes. Other causes of breakdowns may include improperly adjusted spark balls or the
disruption of air gaps by rain, snow, insects, birds, grass, or an accumulation of pollution (soot) on
insulator surfaces.
Small radius conductors
Be careful when using small radius conductors to carry high RF voltages and currents. If the radius is
too small it may cause a local corona, which can lead to a breakdown.
Feedline testing
Test the RF transmission system from the transmitter flange to the antenna before putting the
transmitter into service. This is very important, especially if you are re-using an existing site with a
previously installed feedline. Ensure that the entire system can tolerate the expected peak voltages of
normal operation, especially those occurring during modulation peaks, without breaking down.
Ensure that the antenna system meets or exceeds the standards specified in EIA Standard TR-101-A,
paragraph 8(b), with a normal impedance of 50 ohms at the carrier frequency. The transmitter will
operate with a maximum VSWR of 1.5:1, or with sideband VSWRs of up to 2:1 when the carrier
frequency impedance is 50 ohms. However, overall system performance degrades as the VSWR
increases.
Advances in digital modulation schemes like IBOC and DRM systems require better performance
from antenna systems. To ensure the proper operation during digital broadcasting, ensure that the
VSWR does not exceed 1.4:1 at the carrier frequency ±15 kHz.
In order to achieve the proper sideband symmetry (Hermitian symmetry) needed for IBOC
operation, you may need to adjust the tuning of the antenna system to balance the impedances at the
sidebands. You must perform a full impedance sweep of the antenna system before broadcasting
IBOC. This requires information about phase versus frequency for Hermitian symmetry at the power
amplifier. The information will be provided with the transmitter at time of shipment. For information
about your transmitter’s RF phase, contact Nautel Customer Support.
An ancillary parts kit is shipped with the XR6/XR3. This kit contains hardware needed during the
installation process. The kit includes toroids, spare fuses, screws and other miscellaneous hardware.
Issue 3.0 2009-07-15Page 9-1
XR6/XR3 Pre-installation ManualParts and tools
Documentation
See “XR6/XR3 transmitter manuals” on page ix.
Parts not supplied by Nautel
Some parts and materials required to complete installation are not supplied by Nautel. The parts you
need vary with the installation requirements. The list of parts you normally provide yourself during
installation include:
•A suitable 50 Ω RF output coaxial cable, terminated by the proper connector, complete with
center male connector at the transmitter end.
•All external control and monitor wiring, including the associated terminating devices, conduit and conduit clamps.
•All electrical power cables, including conduit, terminating devices, and conduit clamps.
Parts ordering
You can order replacement parts from your Nautel sales agent, or directly from Nautel through the
Nautel website.
Module replacement program
Nautel offers a module replacement program for customers who require expedited servicing and
replacement of faulty modules. The module replacement program provides immediate replacement
of failed modules with refurbished modules.
•The replacement module is shipped to the customer as soon as the customer reports the
failure. The customer then returns the failed module to Nautel within 30 days using the same
shipping package.
Page 9-2Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualParts and tools
Tools for installation
The tools you need during transmitter installation include the following:
•Digital voltmeter
•Philips screwdrivers, sizes #1 and #2
•Pliers
•Wire cutters
•Slot screwdriver, 5 mm (3/16 inch)
•Metric and Imperial socket set up to 24 mm (15/16 inch)
•Metric and Imperial wrench set up to 25 mm (1 inch)
•Feeler gauge (to measure spark gap)
Issue 3.0 2009-07-15Page 9-3
XR6/XR3 Pre-installation ManualParts and tools
Page 9-4Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualAccessories
Section 10: Accessories
This section describes accessories and optional equipment for the XR6/XR3 transmitter. Accessories
include the following:
•Ac line surge protection
•Automatic antenna transfer control unit - see page 10-2
•Automatic switching system - see page 10-4
•Dynamic carrier control unit - see page 10-4
•Spares - see page 10-4
•Documentation - seepage ix
Contacting Nautel
You can reach Nautel to order parts or for technical assistance at:
A surge protector panel is recommended for all equipment at the transmitter site. The surge
protection panel helps to protect the site from lightning induced voltage transients on the ac power
source or the antenna or ground system. Nautel offers an ac line surge protection panel, which is
suitable for use with the XR6/XR3 transmitter. (Various versions are available, depending on your ac
configuration and supply voltage.) However, you can use any surge protector with at least a 1,500
Joule per phase rating.
Connect the surge protector’s ground terminal directly to the station reference ground using a 10 cm
(4 in.) wide copper strap. Also connect the surge protector’s ground directly to the ac power supply
ground, the transmitter’s grounding point, and the common ground for the site. Ensure that the
common ground is isolated from any other sources of ground (for example, grounding rods not
connected to the station reference ground), to prevent lightning charges from bypassing the surge
protector and passing through the ground and into the site.
Place the surge protector as close as possible to the ac service entrance, minimizing both the physical
and electrical distance between the service entrance and the surge protector. For detailed information
about surge protection, refer to the Nautel Site Protection Manual.
Automatic antenna transfer control unit
The automatic antenna transfer control unit is a 19-inch, rack-mountable assembly that is used in
conjunction with two Nautel AM or FM broadcast series transmitters that are to be connected in a
main/standby configuration. The control unit controls the on/off status of the transmitters by
controlling the status of their safety interlock circuits. It also controls the ac voltage applied to relays
or contactors, to determine the routing of the RF output of the on-air transmitter to the antenna. See
“Automatic switching system” on page 10-4. The control unit allows manual or automatic switching
of the main and standby transmitters. In automatic mode, the forward power levels of both
transmitters are monitored. If the main (on-air) transmitter's RF output falls below a preset threshold
(typically 3 dB), an automatic changeover to the standby transmitter takes place. An interlock override
feature allows the operator to enable the RF output of the standby (off-air) transmitter into a dummy
load for maintenance or troubleshooting.
Page 10-2Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualAccessories
Figure 10.1: Automatic antenna transfer control unit
RF contactor
The RF contactor is an RF output switching device for a main/standby control cabinet that interfaces
main and standby transmitters (less than 15 kW RF output power) between an antenna and a dummy
load. Typically, an automatic antenna transfer control unit controls the RF contactor's position by
applying ac voltage to the 'set' or 'reset' solenoid of the RF contactor. The RF contactor's position
determines the routing of the transmitter outputs to the antenna and dummy load. Micro-switches on
the RF contactor provide interlock control for both transmitters and prevent 'live' switching.
Figure 10.2: RF contactor assembly
Issue 3.0 2009-07-15Page 10-3
XR6/XR3 Pre-installation ManualAccessories
Automatic switching system
The automatic switching system is a changeover rack for the XR6/XR3 that includes an automatic
antenna transfer control unit and an RF contactor. The main component of the automatic switching
system is a double-pole, double-throw latching switch.
Dynamic carrier control unit
The Dynamic Carrier Control (DCC) option is an add-on, DSP-based module for the XR6/XR3
exciter. This system reduces ac power consumption by reducing the carrier power when the
instantaneous modulation level of the transmitter drops below a threshold. The DCC unit supports
Amplitude Modulation Companding (AMC), Dynamic Amplitude Modulation (DAM) and Dynamic
Carrier Control (DCC) algorithms with various selectable carrier compression levels. Enhanced AMC
may also be available.
Spares
spares kit
The spares kit includes fans, fuses, and semiconductors. Contact Nautel Customer Support for details
about the contents of the spares kit for your transmitter.
XR series RF power module
The XR RF power module integrates four modulators and eight amplifier units, with a combined
power output rating of 9.4 kW, including carrier and modulation. It is compatible with all XR series
transmitters.
Figure 10.3: XR RF power module
Page 10-4Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualAccessories
RF Module testing cable and test load
The RF module testing cable allows bench testing and troubleshooting of RF power modules using a
direct connection to the transmitter.
The test cable provides a temporary connection from the transmitter to an RF power module that has
been removed from the transmitter and placed on a workbench. The test cable provides low-level,
safe voltages, that allow the diagnosis of RF power module problems — this is a unique feature of
Nautel transmitters.
The RF power module test load provides a low power load suitable for operating an RF power
module on the test cable only.
Plug-in power amplifier unit
The XR series power amplifier is a broadband, 1,000 watt plug-in unit compatible with all XR series
transmitters.
Figure 10.4: XR power amplifier unit
Issue 3.0 2009-07-15Page 10-5
XR6/XR3 Pre-installation ManualAccessories
Plug-in power modulator unit
The power modulator unit is a 2,000 watt plug-in unit compatible with all XR series transmitters.
Nautel provides a number of support options to help you during pre-installation planning and
preparation:
•Pre-installation consulting
•Installation and commissioning service
•Online documentation - see page 11-3
•On-site support - see page 11-3
•Training - see page 11-3
•Standard warranty - see page 11-4
•Extended warranties - see page 11-7
Pre-installation consulting
Nautel field support specialists are available to answer questions and work with you to ensure that your
site will be ready for the installation of your XR6/XR3 transmitter. For support, contact Nautel Customer Service and request assistance (see “On-site support” on page 11-3).
Installation and commissioning service
Nautel offers an installation and commissioning service to customers who want assistance with
configuring and commissioning a new Nautel transmitter. After the customer completes the
transmitter assembly and installation, Nautel technical personnel will spend up to three days on-site
to help make the ac power, RF and remote connections, and to assist with the configuration and
testing of Nautel equipment.
The customer is responsible for ensuring that the following stages of installation have been
completed, prior to the arrival of Nautel personnel:
•Ac power wiring for the transmitter has been installed and connected at the breaker panel or
the building’s service entrance. If local electrical codes allow Nautel personnel to connect the
transmitter to the ac supply, using the customer's cable, that task is included in this service.
Otherwise, the customer must ensure that an approved electrician is present for this task.
•The customer has prepared the RF coaxial cable – used to connect the transmitter to the
antenna – and installed the required connector. The customer has also installed the RF coaxial cable in place and connected it to the antenna, while leaving the transmitter end of the
cable unconnected.
•Where required, all remote control and monitoring cables have been installed and connected
to the station equipment (e.g., modulation monitor, frequency monitor, and power meter).
•The site has been made ready for the equipment, and adequate protection against lightning
and lightning-induced transients has been provided.
•The transmitter has been unpacked, closely checked for any damage caused by shipping, and
then assembled.
•The following test equipment has been made available at the site:
– Two-channel oscilloscope (with probes)
– Audio signal generator
– Distortion analyzer
– Spectrum analyzer
– Modulation monitor
– Frequency counter
– 50 Ω test load (rated for 150% of carrier power, VSWR less than 1.1:1)
Nautel’s service representative takes full responsibility for commissioning the transmitter, validating
all external interfaces (i.e., the ac supply, RF output, remote control and monitoring equipment) and
checking out the equipment prior to activation. The service representative turns on the transmitter,
performs all adjustments and set-up procedures, and carries out proof of performance tests at the site.
These tests ensure that the transmitter is operating normally in compliance with its specifications.
The service representative also provides a demonstration and a short explanation of the operation of
the transmitter. Finally, the customer signs an Acceptance of Installation Certificate that provides feedback
to Nautel regarding the commissioning service.
Nautel provides documentation online to customers, letting you familiarize yourself with
specifications, operation, maintenance and troubleshooting prior to the delivery of your equipment.
On-site support
If you require on-site assistance, Nautel’s field support specialists can help you prepare your site, and
ensure that your XR6/XR3 transmitter installation can proceed as quickly as possible. For more
information about onsite support, including scheduling and pricing, contact Nautel Customer
Service:
•Telephone: +1.902.823.3900
•Fax: +1.902.823.3183
•Email: support@nautel.com
After business hours (Atlantic time or Eastern time in North America), requests sent by fax or email
will be acknowledged within one working day.
Training
Nautel's SBE-certified broadcast training programs satisfy your day-to-day knowledge requirements.
Students participating in Nautel's broadcast transmitter or RF basics training programs earn one SBE
credit for each completed day of training. Nautel’s comprehensive selection of training programs will
help a customer’s staff develop valuable skill sets, reduce downtime, and make the most of the
customer’s technology investment.
Nautel training programs are made up of individual modules that can be mixed and matched to meet the
customer’s specific training needs. All Nautel training courses are available at the Nautel Training
Center. Training can also be provided at the customer’s facility, for training the customer’s technical
staff on the customer’s transmitter.
All training courses at the Nautel Training Centre combine classroom and hands-on laboratory work
to ensure a balanced learning experience. Many of our classes also include diagnostic lab exercises.
Nautel training courses feature:
•Limited class sizes to ensure maximum student participation and access to equipment
•Labs that focus on the tasks most often performed at the transmitter site.
XR series on-site or factory training
This includes product overview, site and pre-installation, theory of operation, testing and
adjustments, operating instructions, system-level troubleshooting, component-level troubleshooting,
component parts lists, and wiring route sheets.
Standard warranty
Nautel Limited/Nautel Incorporated, hereinafter referred to as Nautel, guarantees all mechanical and
electrical parts of the equipment for a period of 13 months from date of shipment.
1. A "Part Failure" shall be deemed to have occurred when the part has become defective, or
does not have the characteristics required for the specified equipment performance:
(a) When the equipment is operated within the design parameters, and
(b) When the equipment is installed and adjusted according to Nautel's prescribed
procedures as stated in the instruction manual.
2. Nautel shall provide replacements for all "Parts" at no cost to the Customer when they
become defective during the warranty period, and upon the return of the defective part.
3. In the event that a "Part" fails during the warranty period and causes damage to a subassembly that cannot be readily repaired in the field, the entire sub-assembly so damaged
may be returned to Nautel for repair. The repairs will be made without charge to the
Customer.
4. Where warranty replacements or repair are provided under items 2 or 3, Nautel will pay that
part of the shipping costs incurred in returning the part/assembly to the Customer.
5. Warranty replacement parts and repair, which are provided under items 2 or 3, shall be
guaranteed for a period of ninety days from date of shipment or until the end of the original
warranty period, whichever occurs later.
6. Nautel will not assume responsibility for any charges incurred by other than Nautel
employees.
7. Nautel shall have the privilege of investigating whether failures have been caused by factors
beyond its control.
8. Nautel shall in no event be liable for any consequential damages arising from the use of this
equipment.
9. When requesting a warranty repair/replacement, please provide complete and accurate
information. Observe the instructions regarding“Equipment being returned to Nautel” on
page 11-6and provide the information requested.
10. When ordering spare/replacement parts, please provide complete and accurate information.
Refer to the parts list of the Repair manual for ordering information. Provide as much of the
information requested for 'Equipment Being Returned to Nautel' on page two of this
warranty as is practical. The information identified by an asterisk is the minimum required.
Technical assistance
Nautel's field service department provides telephone technical assistance on a 24 hour, seven days a
week basis. Requests by other media (facsimile or e-mail) will be responded to the next working day if
received after Nautel's normal working hours. Contact the appropriate field service centre from the
following:
In order to provide Nautel customers with a fast and efficient service in the event of a problem,
Nautel operates a factory rebuilt, module exchange service which takes full advantage of the high
degree of module redundancy in Nautel equipment. This module exchange service is operated from
Nautel's factory in Bangor, Maine and Hackett's Cove, Nova Scotia. These two locations allow us to
provide a quick turn around service to keep our customers on the air. During the transmitter's
warranty period, up to thirteen months from shipment, repair and exchange of modules is at no
charge to the customer. When the warranty has expired, a charge of 80% of the list price for all
exchanged modules is made. If the faulty module is returned to Nautel within 30 days, a credit is
issued reducing this charge by one half to 40% of the list price. USA customers are required to
contact our Bangor, Maine facility. Canadian and overseas customers should contact our Nova
Scotia, Canada facility.
Equipment being returned to Nautel
For all equipment being returned to Nautel and all requests for repairs or replacements:
•Obtain an RMA number from Nautel (you must have an RMA number to return equipment)
•Mark the item as 'field return'
•Mark the item with the RMA number assigned by Nautel
•Address the item to the appropriate Nautel facility
Complete and accurate information regarding the equipment being returned will ensure prompt
attention and will expedite the dispatch of replacements. Refer to the nameplate on the transmitter
and/or the appropriate module/assembly to obtain name, type, part and serial number information.
Refer to the parts list of this manual or the appropriate service instruction manual for additional
ordering information.
The following information should accompany each request (* denotes minimum required
information):
Nautel's standard 13-month warranty provides excellent coverage and satisfies most customers’
needs. However, if you want extended coverage, Nautel offers one- and two-year Extended Warranty
Plans to cover electrical and mechanical repairs or replacements for all Nautel equipment.
Coverage
The Extended Warranty Plan includes:
•A module exchange program for many common modules and circuit boards (North America
only)
•Toll-free hotline (North America only)
•Necessary labor performed by Nautel authorized personnel to repair the product to meet
factory specifications
Extended Warranty Plans must be purchased prior to the expiration of original 13-month warranty.
One-year Extended Warranty Plans add an additional year (12 months) of coverage after the end of
the customer’s standard 13-month warranty. The two-year plan adds an additional two years (24
months).
Only repairs done at Nautel's facilities or by Nautel authorized personnel will be covered by the
Extended Warranty Plans.
You must ship faulty products back to Nautel, prepaid, and in the original package or in a package
that provides equivalent protection.
Nautel can choose to repair or replace equipment.
Purchasing a one- or two-year Extended Warranty Plan
If the transmitter is still covered by its original 13-month warranty period, you can contact Nautel by
telephone, fax, mail, or email with the model number, serial number and date of purchase.
Once you purchase a Nautel Extended Warranty Plan, you receive an extended warranty plan
certificate, plan number, and a toll-free number (North America only) to call for any service-related
issues.
Using the Extended Warranty Plan
Contact Nautel's Canadian or U.S. service facility by phone, fax, or email as soon as a problem
occurs. The following will be required when contacting Nautel:
•Extended warranty plan number
•Product model number
•Serial number
•Brief description of the problem
If Nautel’s service technicians are unable to solve the problem over the telephone, Nautel will give
you an RMA number. You then return the module or circuit board to a Nautel service facility, so that
Nautel can provide a replacement. Do not ship a component back to Nautel until you have an RMA number.
Page 11-8Issue 3.0 2009-07-15
XR6/XR3 Pre-installation ManualList of terms
Section 12: List of terms
This section defines some of the terms that are used in Nautel documentation.
AES-EBU. Audio Engineering Society/European Broadcasting Union (AES/EBU) is the name of a
digital audio transfer standard. The AES/EBU digital interface is usually implemented using 3-pin
XLR connectors (the same type connector used in professional microphones). One cable carries both
left- and right-channel audio data to the receiving device.
AMC. Amplitude Modulation Companding
Antenna Tuning Unit (ATU). A device that matches the transmitter to the impedance of the
antenna.
B+. The high voltage dc generated by the transmitter’s ac power supply for use within the transmitter.
The B+ voltage is used to supply the transmitter’s modulators and other transmitter circuitry.
Cutback. A reduction in RF output power, caused by a total power limit fault or the occurrence of
three shutbacks within a five second period.
DAM. Dynamic Amplitude Modulation.
DCC. Dynamic Carrier Control.
DSP. Digital Signal Processing.
HD Radio. High Definition (HD) Radio is another term for In Band On Channel (IBOC)
technology. HD Radio is a trademark of iBiquity Digital Corporation.
IBOC. Nautel In-Band-On-Channel technology provides high quality digital audio over existing AM
radio channels.
IPM. Incidental Phase Modulation
NE IBOC. Nautel’s In-Band-On-Channel signal generator. See IBOC. Required for XR series IBOC
installations.
PDM. Pulse Duration Modulation.
Issue 3.0 2009-07-15Page 12-1
XR6/XR3 Pre-installation ManualList of terms
Preset. A setting that controls power level, active exciter, and power scheduler status on a time-of-
day and date basis. Exciters can be configured on a preset for a specific operating mode (for example,
Exciter A - conventional AM, and Exciter B - IBOC). The XR6/XR3 allows you to pre-program up
to six presets.
Shutback. A complete loss of RF output power, caused by any one of a variety of faults, including
high VSWR, low B+ voltage, high RF current, RF drive failure, external interlock or spark gap.
Surge protection board. An electrical panel that protects equipment from electrical surges in the
ac power supply, antenna or site ground caused by lightning strikes.
VSWR. Voltage standing wave ratio. This is an expression of the ratio of forward voltage to reverse
voltage on the feedline and antenna system. An ideal VSWR of 1:1 provides maximum transmitterantenna efficiency.
protection, 2-1
lightning protection, 2-3
line surge protection 10-2
loading conditions, power, 5-2
local corona, RF conductor, 8-2
location for transmitter, 2-1
logic true condition, 6-10
M
mating connector, RF, 2-2
minimum clearances, 3-1
onsite assistance, 11-3
opto couplers, 6-7
oscilloscope, 6-13
output voltage waveform, 6-12
over-capacity, Ac power, 5-2
P
panel, rear, 3-1
parts ordering 9-2
parts, 9-1
peak voltages, RF feedline, 8-2
phases balanced to ground, Ac power, 5-3
planning assistance 11-1
plug-in power amplifier unit (XR PA), 10-5
plug-in power modulator unit (XR MOD),
10-6
pollution, as a trigger of insulator break-
down, 8-2
Issue 3.0 2009-07-15Page IX-3
XR6/XR3 Pre-installation Manual
power amplifier unit (XR PA), 10-5
power consumption 5-2
power consumption, 5-2
power modulator unit (XR MOD), 10-6
power service, 2-1
power source 5-1
power switch assembly, 2-1, 5-2
power transformer, 5-1
preset carrier level, 5-2
preset power level 6-13
preset RF power level, 6-1, 6-7
previously installed RF feedline, 8-2
pricing, support, 11-3
primary winding, power transformer, 5-1
programming format, 5-2