OE3MZC's Smartuner users page


Dedicated to users of the ultimate automatic antenna tuner, or?

Since HAMRADIO in Friedrichshafen ( Germany ) even Europe has seen the new fully automatic antenna tuner model SG-237 from the U.S. company SGC. The fine piece of electronic is promised to handle up to 100 Watts PEP on HF and 50 MHZ into a random wire with just a single koax and additional 12Volt supply voltage. 
One week after Hamradio about six units have been imported to Austria and used for the annual fieldday of the ADL303 Radioclub. Here we will discuss our and your expierience with the SG-237 Smartuner. 
Please send your comments: [email protected] 
SGC237 Smartuner shown on HAMRADIO Features:  

fully automatic antenna tuner for 
1,8- 60 Mhz transforms high or low impedance of a random wire to 50 ohms to present the correct load for HF transveivers like the YAESU FT100 or the ICOM 706 or Kenwood TS50S or any other 100Watt rig. 
Some minimum wire lengths and good grounding are requirements for optimum functionality of the  
new  SG-237 Smartuner.  
It is also available as a printed circuit board only, without any cover or as a portable or mobile version QMS
A nonvolatile memory is used to keep track of once found LC- combinations for specific frequencies to ensure very fast retune. 

Even if the price in the US is just about 295 USD we in Europe had to pay about 500 USD ( 6400ATS) for import including VAT , airshipment and taxes. 
Specifications - SG-237 
HF Frequency Range: 1.8 to 60 MHz 
Power Input Range: 3 to 100 watts (PEP)   40 watts max. on CW 
Input Impedance Range: 45 to 55 ohms 
VSWR: (Typical) Typically less than 1.4:1 
DC Input Requirement: + 13.8 VDC (nominal) 
DC Operating Range: +10.5 to 18 VDC 
Input Current: Average: 300 milli amps 
Random set time: Typical: less than 2 seconds 
Recurrent set time: Typical: less than 10 milliseconds 
Memory Capacity: 170 locations 
Antenna Length: Minimum length of 7 ft. - 3.5 to 60 MHz 
Minimum length of 23 ft. - 1.8 to 60 
Installation: Any position 
Operating Temperature: -35° to +70° C 
Size: 9 x 7 x 1.5 inches (PCB 5.5 x 6 x 1 inches) 
Weight: 2 pounds (PCB 1.25 pounds) 
Case Construction: ABS plastic cover on an anodized aluminum base 
Control Cable: Shielded 4 conductor RG-58 coax with PL-259 connector 
Control Cable Length: 9 feet in length 
you can buy the PCB separately 
a single PCB board hold all components 
very compact size !

REPORTS from USERS of SGC Smartuner:

Here are some comments, hints and tricks , but also some problems with Smartuner SG-237

OE1MHA: The tuner is not tuning every length of wire, but just very specific random wire lengths seem to work well. Especially 23m long wire seems to work very well on all HF bands. 

OE3JKS: could not tune my wire at all! Possibly it was mounted too low? ( just 2 meters above ground) 

OE5MZC: Tuner hangs as soon as I try to match on 50 Mhz. After this it does not retune on HF. No action at all. Reset or Power-Off necessary to cure the problem. But all other bands work well with the Smartuner in the middle of my multiband dipole ( instead of a balun ) Also the cover is not waterproof! The screws often come loose and they are difficult to refit, since they are hidden in the rear aluminium panel. 

OE1PYA: used SGC-237 with a 10m high fibreglass fishing rod vertical ,close to the car. Antenna wire run through the plastic bumper of car and tuner was safely inside the trunk, tuning well on all HF bands. 

OE3XMU: 25m long helically wound wire around 10m long fibreglass tower on top of  7m aluminium mast  with 15m long counterpoise on the ground performed very  well on HF bands. ( worked 28 ITU-zones during one night ) but also problems on 6 meter !? 

Answer from SGC Tech Support: 

Thank you for your email regarding the group of SG-237 owners.  We 
appreciate your comments. 

The SG-237 should provide excellent performance on all bands and 
antennas, as we specify.  However, in your particular situation,  it 
appears that there was corrupted firmware in the MCU.  Replacing the MCU 
should resolve the problem. 

Please advise where and how to dispatch 6 new MCU chips for 
replacement.  We are confident that this will clear up the problem. 

Looking forward to your response. 

Best regards 
SGC Tech Dept. 

HOW to upgrade firmware:
If you encounter erratic tuning behavier of your SGC Smartuner a defective firmware might be the reason.
However it is more likely that bad grounding system is the reason for malefunction of this tuner!.
To change the firmware , remove power supply, loosen all screws and remove the cover. Do not forget to loosen the thightener for the coaxcable before opening the cover.
Locate the MCU chip ( see photo ) .Use the rifght tool to remove the IC from socket. Fit the new MCU-chip in same direction as the old one. Observe polarity. Do NOT use force! Assemble in reverse order and apply power to check improved performance of your SG-237 Smartuner.
MCU chip location
SG-237 Smartuner expierience 
 Have you done some test already??!     Please send your reports ! 
e-mail us about SMARTUNER
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