About SuperDF:

Specifications and Features of
SuperDF Radio Direction Finders

Introduction

This document is written to be useful for both the SD*.* line and the PRO line of SuperDFs. The specifications applicable to only the PRO are italicized.

The patented SuperDF Radio Direction Finder (RDF) is an inexpensive unit for use by professionals or by people who do not necessarily have a radio or electronics background. It can be used with an unmodified Narrow Band FM radio, including scanners and service monitors (not for use with AM radios). Any signal that is contained inside the receiver's bandwidth can be hunted. Since it uses phase information only, signal strength is not a factor. Because of this, an attenuator is not needed, and the system is very resistant to overloading. An "S" meter is not required. The unit can be used at a base station with the antenna mounted on an existing rotor, on a mobile, or on-foot with a handheld receiver or transceiver. The same control unit can service all these functions.

SYSTEM Type

• Manually rotated Phase-Front Detection. [Sometimes erroneously referred to as a Time Difference Of Arrival (TDOA) system.]
• Applications On foot, mobile, or base-station.
• Signal Type AM, FM, CW, MCW, TTY, FSK, and SSB.
• Sensitivity As low as 20 dB below the noise level. (I.e., inaudible signals.)
• Operates to within 1 foot of 1 watt at 150 MHz without overload.

DISPLAYS

• Red & Green LEDs.
• Zero-Center meter.
• Change in Tone-Pitch.
• Each indicates Left-Right information.
• Using Tone-Pitch lets the operator keep his eyes on the road.

POWER

• Two 9 volt transistor radio batteries; a main and a spare.
• Draws typically 24 ma with LEDs on.
• Draws typically 8 ma with LEDs off.
• Stops working at about 6.5 volts.
• Protected against reverse polarity.
• Battery test switch.
• Field replaceable.
• Will operate up to 15 volts
• Must have a floating power source.

TYPICAL BATTERY LIFE

• 60 hours using two alkaline batteries and Tone-Pitch display.
• 20 hours using two alkaline batteries and LED display.
• Signal Averaging 0.1 second for fast response
• Signal Averaging 1 second for noisy signals or multipath.

CONTROL UNIT SIZE

• 2.25 X 3.25 X 6.24 inches.

MEMORY

• Can display Left-Right information for several seconds after carrier stops.

CONTROLS

• On-OFF,
• A-B battery select,
• Battery test switch,
• DF-(monitor) select,
• Tone-LED display select,
• Fast-Slow response time select.
• There are no external control settings which can produce erroneous bearing indications.
• There is an internal switch to select audio phase to match receiver audio phase with which t is used.
• Audio Output is an Internal 8 Ohm speaker or 8 Ohm earphone (with speaker cutoff).
• Earphone not supplied.
• Audio power supplied by the receiver used.
• No field adjustment.

COLOR

The control unit is black with white silk-screened letters.

WARNING!

Changing receiver model will probably require readjustment by maintenance personnel of a timing circuit to match the signal delay time through the receiver being used. This is a simple POT adjustment.

ANTENNAS

The antennas are painted flat-black to make them less obvious in daylight, and virtually invisible at night. The whips are stainless steel and are fully insulated with black heat shrink tubing. Each antenna will DF its entire specified range.

POLARIZATION

• Either vertical or horizontal.
• Mounting left to the buyer.

SDV1-RB

• Frequency Range 100 to 250 MHz.
• Non-folding whips. (No equivalent PRO antenna.)
• Width 24-1/8 inch wide.
• Height 48 inches uncut.

PRO-V1 & SDV1-FRB

• Frequency Range 100 to 250 MHz.
• Fold down for storage or hand carry. Whips cannot be deployed incorrectly.
• Width 24-1/8 inch wide.
• Height 48 inches uncut.

PRO-U1 & SDU1-RB

• Frequency Range 250 to 550 MHz
• Width 12-1/8 inches.
• Height 25-3/4 inches uncut.

PRO-G1 & SDG1.B

• Frequency Range 500 to 1000 MHz
• Width 7-1/8 inches.
• Height 9-3/4 inches

PRO-G1.3 SDG1.3-B

• Frequency Range 550 to 1300 MHz
• Width 5-3/4 inches.
• Height 7-5/8 inches

Contact Information

George (Russ) Andrews, K6BMG

BMG Engineering, Inc.

9935 Garibaldi Avenue

Temple City, CA

91780

USA



Phone:  1(626)285-6963

FAX:	1(626)285-1684  (dedicated line, automatic)

Web:    http://members.aol.com/bmgenginc

(31 Jan 1996)

Send E-mail to grandrews@aol.com.   (A message window will open.)
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