RFL 9780 RFL Electronics Inc.
April 8, 2003 4-8 (973) 334-3100
4.6 TRANSMIT FUNCTIONS
This section covers the configuration requirements which are related to the transmit functions of the
9780. The user must select the transmit frequencies (center frequency and shifts), the transmit power
level(s), and how to combine the two keying input signals.
4.6.1 TRANSMIT FREQUENCIES
The user must know what transmit center frequency and shifts are required for the system. Both the
Transmitter Module, which generates the carrier, and the Output Filter, must be configured.
There are four Output Filters available to cover the specified 30 to 535 KHz carrier frequency.
Normally only one filter is required per installation. Three of the Output Filters have jumpers to select
one of three frequency bands within the overall range of the Module. See Section 10 for details on
selecting and configuring the Output Filter. The Transmitter Module must be set to generate the
required carrier frequencies. There are three banks of direct-reading rotary switches on the module.
The middle bank contains five switches which are used to set the center frequency of the system with
10 Hz resolution. The upper bank sets the ‘up-shift’ frequency using two switches with 10 Hz
resolution. The lower band sets the ‘down-shift’ frequency using two switches with 10 Hz resolution.
See Section 8 for more information on the Transmitter Module.
4.6.2 TRANSMIT POWER (POWER BOOST LEVELS)
The system can be configured for various combinations of output power (1W/10W, 10W/10W, etc).
The output levels are configured using switches SW7-2 through SW7-4 on the Logic Module. See
paragraph 6.3.12 for more information. Note that for systems with external power amplifiers, these
settings will be scaled by the external amplifier. For example with a 50 W external amplifier, a 9780
configured for 10W/10W would be a 50W/50W system, a 1W/10W 9780 would provide a 5W/50W
system. The standard 10:1 power boost ratio can be modified at the factory if required.
4.6.3 KEYING MODES
The 9780 can be configured for 2F Single-Trip, 2F Dual-Trip, 2F Start/Stop, or 3F Dual-Function
Keying. This is configured using switches SW7-7 and SW7-8 on the Logic Module. See Paragraph
6.3.15 for more information.
4.7 RECEIVER FUNCTIONS
There are many user configurable features in the 9780. Two fundamental configuration requirements
include line termination (for impedance matching) and setting the receive frequencies. Adjusting for the
actual receive level is covered in Paragraph 4.8.3. If any external carrier level meter is to be installed,
the system must be configured for the type of meter connected. The Alarm Output Relay has
programmable pick-up and drop-out times and the visual (and external) trip-sent and trip-received
indicators can be configured as latching signals. Trip and Guard processing logic functions are fully
programmable and must be configured prior to placing the 9780 in service. Note that improper
configuration can result in unreliable or faulty operation of the unit. Consult RFL if you have any
questions regarding the proper configuration of the 9780.
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