SGC SG-307, SG-303 User Guide

SG-303/307 WHIP ANTENNA MANUAL

© SGC 2007

HIGH PERFORMANCE HF SSB ANTENNA FOR MARINE AND MOBILE USE

ITEM # 55-27: SG-303 W/ MOUNT / ITEM # 55-67: SG-303 W/O MOUNT
ITEM # 55-28: SG-307 W/ MOUNT / ITEM # 55-69: SG-307 W/O MOUNT

DESCRIPTION

The SG-303 and the SG-307 are designed to radiate efficiently at HF frequencies from 2-30 MHz.
Both antennas provide reliable long range communications. Their short length permits
communication from a vehicle in motion (60 MPH or 100 KPH speed maximum). The antennas
must be used with an antenna coupler (SG-230 or any coupler with a similar specification).

SPECIFICATIONS

Specification

SG-303

SG-307

Maximum Input Power.

500 Watts PEP or CW

150 Watts PEP or CW
Operating Range.

2-30 MHz

2-60 MHz
Primary Loading Resonance:

11 Mhz

8 Mhz
Secondary Loading Resonance

22 MHz

25 MHz
Mounting

High Voltage, 4-way
Ratchet

High Voltage, 4-way
Ratchet
Ratchet mount material:

Stainless Steel

Stainless Steel
Maximum vehicle or boat speed:

60 MPH/100 KPH
(when erect)

60 MPH/100 KPH
(when erect)
Radiation:

Omnidirectional

Omnidirectional
Shipping weight:

10 pounds

8 pounds
Maximum total height:

9 feet

7 feet
Maximum shipping length

4.5 feet

7.5 feet

ITEMS SUPPLIED

1. Loaded whip antenna (in two sections of 4 ft each for the SG-303)

2. 3 iinch, high voltage Delron insulator

3. 4-way stainless steel ratchet mount

4. Special SGC heavy duty, rubber encapsulated base spring

5. 3 ft. of high voltage wire, one end terminated by a ring lug

6. High voltage wall feed-through bushing (hole = .890 inch)

7. 3 ft of ¾ inch wide braided copper ground strap for coupler grounding

8. 12 releaseable tie wraps

9. Lug to connect high voltage wire to coupler

10. Manual

SG-303/307 WHIP ANTENNA MANUAL

© SGC 2007

NOT SUPPLIED AND MAY BE REQUIRED FOR INSTALLATION:

Additional braided ¾ inch wide ground straps, 3 inch copper foil (3 mil thickness), or electrical
stranded wire, gauge 12 or larger of at least 20 feet in length can be used to create an RF
grounding system within the vehicle. In a vehicle made of fiberglass or non-metallic alloys, at least
3 such wires should be connected between the coupler ground and any metallic structures to create
a minimum RF Ground for efficient operation.

VEHICLE INSTALLATION

Select a protected area in the vehicle or boat to allow proper mechanical installation of the coupler.
The coupler should be within 2 feet of the base of the antenna. The SG-303/307 must be mounted
outside in an unobstructed area and at the highest point possible on the vehicle. Recommended
areas are as high as possible and as far from the engine compartment as possible. Typical locations
are shown below:

Proper Whip Installations

Roof Mounting

High on the
Rear Side
Panel

High on the
rear or trunk