SG-231 MANUAL
SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
© 11/00 SGC, Inc.
P.O. Box 3526, 98009 Fax: (425) 746-6384 Tel: (425) 746-6310
E-Mail: [email protected] Website: www.sgcworld.com
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Note: The light bulb might not turn on immediately if the coupler has not yet been
tuned for the frequency of the transmitter. The output power (light-bulb brightness) is
greatest when the coupler is properly tuned.
This test will ensure that the radio and coupler are working properly.
7.0 Coupler Configuration
Schematic Q30102100, sheet 3 is the schematic diagram of the two basic coupler
networks. Note that the
L
network as viewed from the generator, may be configured as
either “C in” or “C out,” whichever is required by the load. In either case, the end of
the network containing the shunt C element will be the
higher
impedance end of the
network.
7.1 Schematic Diagrams
Schematic Q30102100, sheets 1, 2, 3, and 4, are the schematic diagrams of the antenna
coupler. RF input is applied to terminals marked GND and RF on J6, +13.6 VDC is
connected to the terminals marked GND and +13.6 VDC on J10, and an appropriate
antenna and ground system are connected to the high voltage screw and stainless steel
ground stud respectively. The TND line on J10 is connected to the SG-2000 or the
SmartLock Pro. This line
cannot
be connected to both units simultaneously.
7.2 Tuning Process
An array of detector devices in the SG-231 monitor the antenna system impedance,
reactance signal, and the VSWR load when RF power is applied to the unit. The coupler
also monitors forward power, since the control computer requires an indication of both
forward and reflected power in order to allow tuning to proceed. The computer uses
the forward power detector as a check to ensure that the measurements made are
applied RF and are not spurious levels from the data conversion system. The SG-231
will proceed to tune
only
when enough forward power is present to confirm this check.