The SmartLock provides two external controls for the SG-230. A locking function prevents automatic retuning despite changing antenna loads (eg. from passing trucks or passing beneath bridges when mobile). A reset function forces the Smartuner into a retune cycle until the signal is transmitted again, or allows receiver/scan in a broadband antenna mode. A 'tuned' led also indicates locally when the SGC-230 achieves a match.
Although SGC can supply this optional unit, it's easy to build your own version from the circuit details found in the 230's manual:
The SmartLock circuit:
What's a SG-230 Smartuner?
The SG-230 is, in fact, an antenna coupler. It intelligently couples any length of antenna from about 3 to 27 meters. No preliminary tuning is required, and the Smartuner will operate with any HF transceiver in the 1.6 to 30 MHz range and output power from 3 to 200 Watts. The SG-230 automatically evaluates and switches 64 input and 32 output capacitance combinations, plus 256 inductance combinations in a 'pi' network - over half a million precision matches are possible. The Smartuner then remembers the chosen frequency and tuning values and automatically reselects those values - in less than 10mS, each time you select the frequency.
These features provide great logistical and operational flexibility for dxpeditioners. No more lugging around complex multi-trap antennas or re-tuning elements because of site differences, QSYing takes seconds - always with a <1.5 SWR and housed in a robust weather resistant case ...it's no wonder these units are used by the military and government agencies.
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