SMARTLOCK
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.