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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desired radio is in place. The coupler finds a tuning solution, as indicated by the
remote tune indicator going on, but then resumes hunting. In a majority of cases this
will be caused by an overly sensitive transmitter final amplifier section or by inadequate
shielding around the amplifier.
We know of several radios that oscillate relatively easier than most radios because they
are housed in a plastic case. A plastic case does not provide an adequate shield for
serious RF components. In some of these cases, putting grounded foil around the radio,
or changing the radio location and orientation, has changed the symptoms. But if you
want quality performance, select a solid radio.
Power supply
. Power supplies have been known to cause problems for HF users
because they change voltage when the load on them changes. If the transmitter is
drawing heavy current, as transmitters do when they are running at peak input power,
the voltage to the antenna coupler may change enough to cause the coupler to either
drop into a reset mode (under +11 VDC being present) or, the transmitter final
amplifier impedance may change greatly, thus changing the tuning solution.
To alleviate this condition, remember to use a power supply that has both adequate
current handling capacity and good dynamic regulation. Better yet, use a regulated
power supply of an adequate rating.
10.4 A Final Pointer on Troubleshooting
Remember that the SG-231 is an excellent piece of equipment that will give outstanding
performance. If you have a problem with the coupler finding a tuning solution, you
should
change one variable at a time
.