Antennas:
1. Whip
2. Backstay (marine, sail)
3. Dipole centerfed
4. Dipole with feedline
5. Loop (small) 2 x 2 ft. multi-turn
6. Loop (large) 10 ft. and up single turn
7. Longwire

For marine, aviation, commercial and radio amateur applications.
This product is designed with high density surface mount components on a 4 layer PCB, providing high efficiency, reliability and performance. The unit is fully waterproof (under 2 ft of water over 24 hour period). 

The PCB is mounted on a sturdy chassis plate which provides an excellent electrical and RF ground system. The case is waterproof and protects the complete unit.

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 MHz
Installation: Any position
Operating Temperature: -35° to +70° C
Size: 9L x 7W x 1.85H inches (22.9L x 17.8W x 4.7H cm)
PCB 6L x 5.5W x 1.2H inches (14L x 15.24W x 3.05H cm)
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