Heathkit GD-48 User Manual

Heathkit of the Month #53:
by Bob Eckweiler, AF6C
GENERAL PRODUCTS
Heathkit GD-48
Metal Locator.
Introduction:
Buried Treasure? Aye Matey, I was saving this
series of Heathkits for September as that is the
month of “Talk Like a Pirate Day” which falls
on the 19th. Alas, so does the OCARC gatherin’.
I expect a fun time!
However, our rotating editor this month is Ken,
W6HHC, and since he passed along manuals for
the GD-48 and GD-348, I thought I’d honor him
with an article on them for his turn as editor.
I’m sure many a pirate of olde would have liked
to have a metal locator for finding those treas-
ures that they buried, only to later realize the
map they made was later used at the bottom of
the parrot’s cage.
Heathkit Metal Locators:
Heathkit used the nomenclature “metal ‘loca-
tor’” instead of “metal ‘detector’” for their
treasure seeking products. Heathkit produced
four models over the years that I’m aware of.
The first was the GD-48 which was listed as
new in the 1969 Summer catalog. The Deluxe
GD-348 followed in 1972 and sold concurrently
with the less expensive GD-48 for five years.
Around 1978 Heathkit introduced the GD-1190,
a third model designed specifically for hunting
small coins. In ads it was called the “Coin-
Track”. Around 1979 the last of the Metal Loca-
tors, the deluxe GD-1290 “GroundTrack” was
released.
Table 1 gives the production dates as best I can
determine with the catalogs in my files.
The Heathkit GD-48 Metal Locator:
The first Heath-
kit metal locator,
the GD-48 origi-
nally cost $59.95.
By 1976 the price
had increased to
$69.95; but in
the fall of that
year it was offered
again for $59.95
on a “save $10”
special. The last
catalog (1977) I
have showing it
listed had the
price back at the
original $59.95.
The GD-48 is
shown in Figure
1. It weighs 4
lbs. and has a
10.5” diameter coil housing. The arm length is
adjustable from 26” to 36”. It is powered by a
NEDA #1602 9-volt battery (Heath part #
GDA-48-1). This is a different battery than the
common 9V battery used in so many products
today. It is rated at 850 ma/hr and measures
approximately 1.3” x 1.4” x 2.7”. (The Eveready
part # is 246). These batteries now run about
$11.00 each and will power the GD-48 for
about 80 hours of operation. The cheaper,
more available, NEDA #1604 may be used but
will provide shorter operation time. The man-
HOM rev. new Heathkit of the Month #53 - GD-48 Metal Locator
Copyright 2014, R. Eckweiler & OCARC, Inc.! Page 1 of 7
Heathkit Metal ‘Locators’:
Model Name From To
GD-48 (none) 1969 1977
GD-348 (none) 1972 1981
GD-1190 “CoinTrack” 1978 1983
GD-1290 “GroundTrack” 1979 1985
Table 1
Fig. 1 Heathkit GD-48

Heathkit GD-48 Specifications

General

Brand	Heathkit
Model	GD-48
Category	Metal Detector
Language	English

Summary

Heathkit Metal Locators: An Overview

Introduction and Model Listing

Article introduction, mention of "Talk Like a Pirate Day", and listing of four Heathkit metal locator models.

Heathkit GD-48 Metal Locator Details

Introduction to the GD-48, its price history, weight, coil size, and battery requirements.

GD-48 Assembly and Circuitry

Details on how the GD-48 is assembled, including circuit boards, coils, and control panel components.

GD-48 Operation, Alignment, and Final Assembly

Explanation of GD-48 operating modes, sensitivity adjustments, alignment procedures, and final assembly steps.

Heathkit GD-348 Deluxe Metal Locator

GD-348 Overview and Specifications

Details on the GD-348, its weight, battery life, coil housing, and adjustability compared to GD-48.

GD-348 Circuitry and Features

Explanation of the GD-348's advanced circuitry, including transistors, diodes, and the coil nulling circuit.

GD-348 Accessories

Listing of accessories available for the GD-348, including battery, headphones, and carrying case.

Heathkit GD-1190 CoinTrack Metal Locator

GD-1190 Overview and Technology

Introduction to the GD-1190, its design for coins, weight, dimensions, and unique coil system.

GD-1190 Integrated Circuits and Controls

Details on the GD-1190's use of ICs, transistors, diodes, and external controls like volume and mode.

GD-1190 Accessories

Accessories offered for the GD-1190, such as a nicad battery pack, Superex headphones, and a carrying case.

Heathkit GD-1290 GroundTrack Metal Locator

GD-1290 Overview and Features

Introduction to the GD-1290, its price, advanced circuitry, induction balance system, and comparison to GD-1190.

GD-1290 Accessories

Accessories for the GD-1290, which are the same as those for the GD-1190.

GD-48 User Interview and Feedback

An interview detailing user experiences with the GD-48, including ease of build, calibration, and operational issues.

GD-1290 GroundTrack Marketing and Specifications

GD-1290 GroundTrack Features

Description of the GD-1290's capabilities in finding valuables, its professional design, and waterproof search head.

GD-1290 Specifications and Pricing

Technical specifications for the GD-1290, including sensitivity, detection method, power requirements, and kit price.