RADIAC SET AN/VDR-2 NSN 6665-01-222-1425

TM 11-6665-251-10
OPERATOR’S MANUAL
RADIAC SET
A N / V D R - 2
NSN 6665-01-222-1425
HEADQUARTERS, DEPARTMENT OF THE ARMY
1 MARCH 1988
Distribution authorized to the Department of Defense and DOD contractors only for
official use or for administration or operational purposes. This determination was
made on 13 November 1987. Other requests for this document will be referred to
Commander, US Army Communications-Electronics Command and Fort Monmouth,
ATTN: AMSEL-ME-P, Fort Monmouth, NJ 07703-5000.
DESTRUCTION NOTICE—Destroy by any method that will prevent disclosure of
contents or reconstruction of the document.

TM 11-6665-251-10
Technical Manual
HEADQUARTERS
DEPARTMENT OF THE ARMY
No. 11-6665-251-10 Washington, DC, 1 March 1988
Operator’s Manual
Radiac Set
AN/VDR-2
(NSN 6665-01-222-1425)
REPORTING ERRORS AND
RECOMMENDING IMPROVEMENTS
You can help improve this manual. If you find any
mistake or if you know of a way to improve the
procedures, please let us know. Mail your letter or
DA Form 2028 (Recommended Changes to Publications
and Blank Farms) direct to: Commander, US Army
Communications-Electronics Command and Fort
Monmouth, ATTN: AMSEL-ME-MP, Fort Monmouth, New
Jersey 07703-5000. In either case, a reply will be sent
to you.
i

TABLE OF CONTENTS
CHAPTER 1. INTRODUCTION
Para- Page
graph
Section I.
General
Scope . . . . . . . . . . . . . . . . . . . . . 1-1
Maintenance Forms,
Records, and Reports . . . . 1-2
Reporting Equipment
Improvement
Recommendations (EIR) . 1-3
Administrative Storage . . . . 1-4
Destruction of Army
Electronics Materiel. . . . . 1-5
Nomenclature
Cross-Reference List . . . 1-6
List of Abbreviations and
Acronyms . . . . . . . . . . . . . . . 1-7
Glossary . . . . . . . . . . . . . . . . . . . 1-8
1-1
1-2
1-2
1-2
1-3
1-3
1-3
1-4
Section Il. EQUIPMENT DESCRIPTION
AND DATA
Equipment Characteristics,
Capabilities,
and Features . . . . . . . . . . . . 1-9 1-5
Description of
Components . . . . . . . . . . . . . 1-10 1-6
Equipment Data . . . . . . . . . . . 1-11 1-10
Section III. TECHNICAL PRINCIPLES OF
OPERATION
ii
Equipment Function . . . . . . . 1-12 1-14

TABLE OF CONTENTS (CONTINUED)
CHAPTER 2. OPERATING
INSTRUCTIONS
Section I. DESCRIPTION AND
USE OF CONTROLS
AND INDICATORS
Para- Page
graph
Equipment Controls
and Indicators . . . . . . . . . . . 2-1 2-1
Section II. PREVENTIVE
MAINTENANCE
CHECKS AND
SERVICES (PMCS)
Preventive Maintenance. . . 2-2 2-4
Routine Checks . . . . . . . . . . . . 2-3 2-4
Section III. OPERATION UNDER
USUAL CONDITIONS
Assembly and Preparation
for Use . . . . . . . . . . . . . . . . . . 2-4 2-6
Equipment Applications . . . 2-5 2-17
Automatic Testing During
Operation . . . . . . . . . . . . . . . 2-6 2-22
Normal Operating
Procedures . . . . . . . . . . . . . 2-7 2-25
Operation in Unusual
Weather . . . . . . . . . . . . . . . . 2-8 2-42
Operation Inside Shelters . 2-9 2-43
Emergency Procedures . . . . 2-10 2-43
iii

TABLE OF CONTENTS (CONTINUED)
Para- Page
graph
CHAPTER 3. OPERATOR
MAINTENANCE
INSTRUCTIONS
Troubleshooting
Procedures . . . . . . . . . . . 3-1 3-1
Battery Replacement . . . . 3-2 3-2
APPENDIX A. REFERENCES . . . . . . . . . . . . . . . . . . . A-1
B. COMPONENTS OF
END ITEM AND
BASIC ISSUE ITEMS
LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
Section I. INTRODUCTION . . . . . . . . . . . . . . . . . . . . B-1
II. COMPONENTS OF END
ITEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3
III. BASIC ISSUE ITEMS . . . . . . . . . . . . . . B-5
APPENDIX C. EXPENDABLE
SUPPLIES AND
MATERIALS LIST . . . . . . . . . . . . . . . C-1
Section I. INTRODUCTION . . . . . . . . . . . . . . . . . . . . C-1
iv
II. EXPENDABLE
SUPPLIES AND
MATERIALS LISTS . . . . . . . . . . . . . . . . C-2

CHAPTER 1
INTRODUCTION
Section I. GENERAL INFORMATION
1-1. SCOPE
Type of ManuaI: Operator’s Manual
Model Number and Equipment Name:
AN/VDR-2 Radiac Set, herein
referred to as radiac set.
Purpose of Equipment:
Used to locate and
measure radioactivity
in the form of gamma
rays and beta
particles, Displays
dose rates and total RADIACMETER
accumulated dose
resulting from a
fallout field.
PROBE
1-1

1-2. MAINTENANCE FORMS, RECORDS
AND REPORTS
a. Reports of Maintenance and Unsatisfactory
Equipment. Department of the Army forms and
procedures used for equipment maintenance
will be those prescribed by DA Pam 738-750, as
contained in Maintenance Management Update.
b. Report of Packaging and Handling
Deficiencies. Fill out and forward SF 364 (Report
of Discrepancy (ROD)) As prescribed in AR 735-
11-2/DLAR 4140.55/NAVMATlNST
4355.73B/AFR 400-54/MCO 4430.3H.
c. Discrepancv in Shipment Report (DISREP)
(SF 361). Fill out and forward Discrepancy in
Shipment Report (DISREP) (SF 361) as prescribed
in AR 55-38/NAVSUPINST 4610.33C/AFR 75-
18/MCO P4610.19D/DLAR 4500.15.
1-3. REPORTING EQUIPMENT IMPROVEMENT
RECOMMENDATIONS (EIR)
If your equipment needs improvement, let us
know. Send us on EIR. You, the user, are the
only one who can tell us what you don’t like
about the design. Put it on an SF 368 (Quality
Deficiency Report). Mail it to Commander, US
Army Communications-Electronics Command
and Fort Monmouth, ATTN: AMSEL-ME-MP, Fort
Monmouth, New Jersey 07703-5000. We’ll send
you a reply.
1-4. ADMINISTRATIVE STORAGE
Administrative storage of equipment issued to
1-2

and used by Army activities will have preventive
maintenance performed in accordance with the
PMCS charts before storing. When removing the
equipment from administrative storage the PMCS
should be performed to assure operational
readiness.
1-5. DESTRUCTION OF ARMY
ELECTRONICS MATERIEL
Destruction of Army electronics materiel to
prevent enemy use shall be in accordance with
TM 750-244-2.
1-6. NOMENCLATURE CROSS-REFERENCE LIST
Common names are used when the major components
of the radiac set are mentioned in this
manual.
Common Name
Radiac Set
Official Nomenclature
Radiac Set
AN/VDR-2
Radiacmeter Radiacmeter lM-243/VDR-2
Probe
Pouch
Probe, Radiac DT-616/
VDR-2
Pouch, Radiac Set
Strap
Strap, Radiac Set
1-7. LIST OF ABBREVIATIONS AND
ACRONYMS
Acronyms are spelled out the first time they appear
in this manual. A list of abbreviations and acronyms
follows:
1-3

Gy
µGy
cGy
Gy/hr
µGy/hr
cGy/hr
NBC
radiation absorbed dose
(gray)
microgray
centigray
grays per hour
micrograys per hour
centigrays per hour
nuclear/biological/chemical
1-8. GLOSSARY
Dose
Rate
Dose
Gamma
Ray
An amount of radiation given off or
absorbed within a given period of time.
(µGy/hr, cGy/hr, Gy/hr).
An accumulative amount of radiation
given off or absorbed. (µGy, cGY, GY).
Electromagnetic radiation of high energy
(high penetration).
Beta
Particles
Negatively charged particles moving at high
speed (low penetration).
X-rays
Auto
ranging
Electromagnetic radiation of high energy
having wavelength shorter than those in
the ultraviolet region (low penetration).
The AN/VDR-2 display will automatically
provide the proper readings and units over
its entire operating range without the
need for mechanical switching or other
operator actions.
1-4

Attenuation
Factor
A multiplying number assigned to
vehicles or shielded enclosures to
account for the attenuation of
gamma radiation by the vehicle
or the enclosure.
Section II EQUIPMENT DESCRIPTION AND
DATA
1-9. EQUIPMENT CHARACTERISTICS,
CAPABILITIES, AND FEATURES.
CHARACTERISTICS
● Lightweight
● Easy to use
Battery operated
Self-testing during operation or on demand
by operator
● Autoranging
CAPABILITIES
● Detects, measures, and displays level of
gamma radiation dose rate from 0.01 µGy/hr.
to 100 Gy/hr.
● Detects and displays level of beta particle
dose rate from 0.01 µGy/hr. to 5 cGy/hr.
● Measures, stores, and displays accumulated
dose from 0.01 µGy to 9.99 Gy.
1-5

● Flashes display to indicate reduced-accuracy
condition when measuring dose rates from
10 Gy/hr. and above.
FEATURES
● Liquid crystal display (LCD) shows three digits,
decimal point, and unit of measure for dose
rate or accumulated dose; also indicates
low batteries and faults
● Can be vehicle mounted with vehicle power
actuating alarms and intercoms; computes
and displays dose rates external to vehicle
● Audible or visual alarm independently preset
for dose rate and accumulated dose
1-10. DESCRIPTION OF COMPONENTS
The radiac set is made up of four separate pieces
of equipment:
● Radiacmeter
● Probe
● Pouch
● Strap
1-6
NOTE
Radiacmeter and probe are serialized and
must be kept together as a set.

The functions of the major components of this
equipment are:
RADIACMETER - Contains
batteries, controls,
indicators, and
electronics needed to
measure and display
dose rate, dose, and
other indications.
LOUDSPEAKER - Provides
audible alarm
DISPLAY - Shows
dose/hr or accumulated
dose, low batteries,
alarm set points, and
test and fault indicators.
1-7

BATTERY WELL COVER
Encloses battery well
containing three dry cell
batteries providing power
to the radiac set.
CONVERTER CABLE
RECEPTACLE (SHOWN
WITH CAP IN PLACE)
Connects radiacmeter to
vehicle power converter
cable.
1-8
CAUTION
The radiac set will not operate with probe
detached and can be damaged if probe is
attached or detached with PWR switch in
ON position.

PROBE - Attaches to
radiacmeter with coil cord and
connector; contains two
detectors, high-voltage power
supply, and other circuits.
PROBE RECEPTACLE
- Accepts plug from
radiacmeter cable.
WARNING
The high range
detector contains 1
nanocurie of Thorium
232, controlled disposal
required in accordance
with AR 385-11.
HOUSING - Contains
low-range detector and
electronic circuitry.
DETECTOR GUARD -
Protects low-range detector,
keeps moisture out of probe.
COVER - Protects detector
against damage; can be used
closed to detect gamma
radiation, must be opened to
detect beta particles.
1-9

POUCH - Holds radiacmeter
and probe during operation or
transport and stores spare set
of batteries. May be attached
to web belt with belt loops.
1-11. EQUIPMENT DATA
ENVIRONMENTAL
Altitude operating To 15,000 feet
range:
(4,572 m) above
sea level
Humidity:
95 percent
Temperature operating
range: -51 to 120°F
(-46 to +49°C)
1-10

Storage temperature
range: -60 to 160°F
(-51 to + 71°C)
Water resistance:
Immersion proof to a
depth of 3 feet
(914.4 mm) of
water for 2 hours
WEIGHTS AND DIMENSIONS
Radiac set in pouch:
Weight:
Length:
Width:
Depth:
4.6 pounds (2.08 kg)
9.125 inches (232 mm)
6.875 inches (175 mm)
3.125 inches (79 mm)
POWER
Main power,
all weather
Three BA-3090 dry
batteries in parallel
(9 V dc) (Item 1, Appx C)
Vehicle power
(when vehicle
mounted):
Main Power
battery life:
24 V dc
100 hours (minimum)
1-11

OPERATIONAL
Detectors:
Range:
a) Low-range detector
(dose rate):
b) Low-range detector
(accumulated
dose):
c) High-range detector
(dose rate):
d) High-range detector
(accumulated
dose):
Two detectors (lowrange
for gamma and
beta radiation, highrange
for gamma radiation),
both located in
probe at approximately
the same location.
0.01 µGy/hr
to 5C Gy/hr.
0.01 µGy to
9.99 Gy.
3 cGy/h to
100 Gy/Hr.
0.01 µGy to
9.99 Gy.
1-12

Overall detecting range:
Dose rate:
Accumulated
dose:
Accuracy:
Dose:
Alarms:
0.01 µGy/hr. to
100. Gy/hr for
gamma rays and
0.01 µGy/hr. to
5 C Gy/hr for beta
radiation
0.01 µGy to
9.99 Gy.
Dose rate: ±20 percent (overall
system error) up to
10.0 Gy/hr.
±25 percent (overall
system error) up to
100 Gy/hr.
±20 percent (overall
system error) up to
9.99 Gy.
Audio and visual independently
adjustable
to any level from
0.0 µGy/hr. to 100
Gy/hr. for dose rate
and 0.01 µGy to
9.99 Gy for
accumulated dose.
1-13

Section III. TECHNICAL PRINCIPLES
OF OPERATION
1-12. EQUIPMENT FUNCTION
1 Gamma rays and beta particles
from radioactive source travel in
all directions.
1-14
2 Two detectors in probe produce
electrical signals on contact with
gamma rays and beta particles.

3 Radiacmeter converts signals
from probe into dose rates and
accumulated dose; activates
alarm when preset alarm levels
ae exceeded.
4 Display shows dose rate and
accumulated dose values, alarm
set levels, battery conditions,
and test and fault indicators.
5 Control panel switches and
indicators permit operator to set
alarm levels for audible or visual
display, select display readings,
and perform equipment tests.
1-15/(1-16 Blank)

CHAPTER 2
OPERATING INSTRUCTIONS
Section I. DESCRIPTION AND USE OF
CONTROLS AND INDICATORS
2-1. EQUIPMENT CONTROLS AND
INDICATORS
a. TOGGLE SWITCHES AND ALARM LIGHTS
RATE AND DOSE LIGHTS - Illuminate
when dose rate or accumulated dose alarm
set points are exceeded and alarm is set to
VlS.
POWER - Turns unit ON or OFF.
THREE-POSITION ALARM
● OFF (center) - NO alarm occurs.
● AUD (top) - Alarm sounds when either
alarm set point is exceeded.
● VIS (bottom) - RATE or DOSE light
illuminates when either alarm set point is
exceeded.
2-1

. PUSHBUTTONS
CLEAR/TEST - Pressed to start operating
test; used with other buttons to perform
various test functions.
DOSE PER HOUR - Used with other
buttons to:
Set dose rate alarm.
Display dose rate alarm set point
Clear accumulated dose.
ACCUMULATED DOSE - Pressed to
display accumulated dose; used with other
buttons to perform various functions.
ATTENUATION - Press to display dose
external to vehicle when vehicle mounted;
used with CLR/TEST button to read
attenuation factor.
2-2

DOSE UNITS - Proper symbol (µGy, cGY, Gy)
activated automatically according to
radiation reading.
2-3

Section II. PREVENTIVE MAINTENANCE
CHECKS AND SERVICES (PMCS)
2-2. PREVENTIVE MAINTENANCE
Preventive maintenance consists of routine checks
of the equipment before and after each mission, or
at any time they are necessary. Routine checks
include cleaning, dusting, and washing the set;
checking for worn cables; replacing receptacle
covers; and putting away items that are not used.
Problems discovered during routine maintenance
should be referred to organizational maintenance.
2-3. ROUTINE CHECKS
Routine checks to be made of the radiac set are:
● Check all connecting cables, receptacles, and
plugs for cracks and breaks.
CAUTION
Turn unit off before disconnecting
or reconnecting probe.
● Check that cable receptacle pins are unbroken
and straight. There should be three pins in the
vehicle mount receptacle on the back of the
radiacmeter and six in the receptacle located
on the probe.
2-4

CONTROL AND DISPLAY PANEL
●
●
Check for loose or broken display lights or
light covers.
Inspect panel toggle switches and
pushbuttons for ease of movement or
evidence of mechanical damage.
OUTSIDE SURFACES AND POUCH
Remove dust, moisture, and loose dirt
from outside surfaces of radiacmeter and
probe with clean soft cloth.
Remove grease, fungus, and ground-in
dirt from equipment pouch.
BATTERIES
●
●
Inspect battery well gasket (see para
2-4a). Refer radiac set to higher level of
maintenance only if gasket will no longer
seal.
Inspect battery contacts; remove any
corrosion using pencil eraser.
2-5

Section III. OPERATION UNDER
USUAL CONDITIONS
2-4. ASSEMBLY AND PREPARATION FOR USE
a. BATTERY INSTALLATION/REPLACEMENT
(1) Make sure PWR switch is OFF (down).
(2) Loosen, but do not remove,
captive screws.
2-6

CAUTION
When batteries are removed
from the radiac set memory
is retained for only 5
minutes.
(3) Remove battery well cover
and three batteries.
2-7

. INSTALLING RADIAC SET IN POUCH
(1) Orient pouch so that tap cover is open
and away from you. Install probe in the left
compartment by passing the straight
section of the tail card nearest the probe
connector through the opening in the
compartment flaps. (Note the orientation of
the high range assembly.) Push probe to the
bottom of pouch.
2-8

(2) Store coil cord at the bottom of the right
hand compartment. Install radiacmeter
directly above coil cord as shown.
RADIACMETER
COIL CORD
2-9

c. PREOPERATIONAL TEST EXPLANATION
Before each mission, a series of preoperational
tests must be performed to
make sure that the radiac set is operating.
The radiac set is self-testing and the preoperational
tests are performed automatically
by the equipment. The operator
is required to reposition the alarm switch
and observe closely that the proper displays
are shown for the test being conducted.
NOTE
A summary of these tests is listed in
sequence below. Although these tests seem
difficult at first, they are easy to perform
after following the sequence a few times.
(1) Segment Test - Segments of the digital
display, decimal points and unit readout are
displayed for about 10 seconds to
determine that all display segments are
working. The alarm test (step (2) below),
must be performed during the 10
seconds the segments are displayed.
2-10

(2) Alarm Test - Operator switches ALM to all
positions to check that the alarm sounds and
shuts off and that the lights work at the proper
times.
(3) Digit/Unit Test - After the segment test, the unit
automatically proceeds through the sequence of
numbers, decimal places, and dose units to test
that they are working in the proper order. This
test and the following electrical tests take about
60 seconds.
(4) Electrical Tests - Immediately following the
sequential displays, a series of eight internal
electrical tests occurs. During these tests, onedigit
numbers may appear on the display. These
are the code numbers related to the test being
made and you can ignore them.
2-11

NOTE
All of the following paragraphs must be
read before starting test procedures.
d.
(1)
(2)
(3)
PREOPERATIONAL TEST PROCEDURES
Set PWR to ON (up).
Set ALM switch to AUD (up).
Press and hold CLR/TEST button until
alarm sounds 2 seconds, then release.
(4)
When segment display appears, check that
your display is exactly as shown here, and
then perform all of step (5) within 10 seconds.
2-12

(5) Set ALM switch to OFF (center). Alarm
sound stops.
Set ALM switch to VIS (down). RATE and
DOSE lights come on.
Set ALM switch back to AUD (up). Lights
go out, alarm sounds.
Set ALM switch to OFF (center).
(6) At the end of the 10-second segment test,
the digit/unit test begins with three zeros
and the sequence shown. Check each
display in the sequence for correctness of
all characters, including decimals.
2-13

(7)
During the electrical tests that start
immediately after the 999Gydisplay, you
may see one-digit codes on the display. You
can ignore these codes.
(8)
If all tests are OK, after 10 to 60 seconds, a
flashing 9 appears with the pulsating alarm.
When you see the flashing 9, proceed to
step (10) below.
FLASHING
(9)
If there is a fault discovered during this test,
a flashing 0 appears and the alarm
pulsates. Turn unit OFF.
FLASHING
2-14

(10) Press and release CLR/TEST button.
Preoperational tests are complete. Display again
shows the three zeros (a) and then indicates dose
rate, which is variable (b). Radiac set is ready for
normal operation.
CLR/TEST
BUTTON
2-15

(11) If any of the following events occur during
the preoperational tests, turn unit OFF and
send to organizational maintenance for
repair.
Power does not come on (step 1).
Alarm does not sound (step 3).
Decimal points, dose units, or any segment
of the display are not in position or
otherwise not exactly as shown (step 4).
● Alarm does not turn off (step 5).
RATE and/or DOSE lights do not come on
(step 5).
● Alarm does not turn on again (step 5).
● Digit/unit test are not displayed in entirety,
in sequence exactly as shown (step 6).
● The electrical tests end with the display
showing a flashing 0 (step 9).
NOTE
When performing preoperational tests in
an area where the background radiation is
unusually low or when the probe is
shielded, it is statistically possible for the
high range tube not to produce a count in
the time allowed in the test. This will cause
a flashing zero to appear when in fact no
fault exists. If the numeral 7 appears prior
to a flashing zero, repeat the preoperational
test. If a flashing 9 appears on
the retest no fault exists. If the flashing zero
repeats, refer the unit to maintenance.
2-16

2-5. EQUIPMENT APPLICATIONS
There are three methods used to locate radiological
contamination - Surveying, Monitoring, and
Ground Radiological Reconnaissance:
● Surveying - Surveys are conducted to find
the extent and intensity of contamination.
There are two types, aerial and ground.
NOTE
To perform aerial surveys, auxiliary
equipment is required which is not
supplied with the AN/VDR-2.
● Aerial surveys cover a large area faster
than other methods. They are more flexible
and require fewer personnel and less
exposure of personnel.
● Ground surveys use unit equipment and
can be performed in any type of weather or
at night. They are more accurate than aerial
surveys.
Monitoring - Monitoring is performed to
determine the presence and intensity of
residual radiation.
Area monitoring is performed periodically or
continuously to provide early warning and
useful radiological data.
● Personnel, food, and equipment monitoring
is performed to detect beta and low levels of
gamma radiation.
2-17

●
Ground Radiological Reconnaissance (GRR)
- GRR is the process of detecting radiation
and measuring it before a unit moves into
or through an area. Normally, the AN/VDR-
2 will be mounted and attached to vehicle
power.
NOTE
When monitoring for beta radiation, the
audible alarm set point should be used. This
allows the operator to pay attention to
positioning the probe rather than watching
the visual display. Performance of all
radiological measurements, regardless of
mode of operation, shall be in accordance
with FM 3-3 and FM 3-5.
a. SURVEY AND MONITORING MODES
In the survey or monitoring modes,
the operator wears the radiac set in
the pouch with the PWR switch in the
ON position. The probe can be carried
either in the pouch or held in the
hand, as desired.
2-18

The probe cover, located at the end of
the probe, is closed when measuring
gamma radiation. Detection is
provided by both low-range and highrange
detectors located in the probe.
The radiac set autoranges from low to
high range (0.01 µGy/-hr to 100
Gy/hr.) smoothly and without
interruption.
CAUTION
The window guard may be ruptured by
sharp objects. Use extreme care to protect
window guard when probe window is open
(when monitoring for beta radiation).
When monitoring for beta radiation,
the probe must be hand held, and the
probe window cover must be open to
allow beta particles to enter the
window of the low-range detector.
Only the low-range detector is capable
of detecting beta particles. The range
of beta radiation is 0.01 µGy/hr to 5
cGy/hr.
2-19

. GROUND RADIOLOGICAL
RECONNAISSANCE (VEHICULAR
OPERATION)
CAUTION
The radiacmeter batteries must be removed
when using vehicular power.
When used in a vehicle, the radiac set is placed
in a mount and installed using an installation kit.
The mount(MT-6123/VDR-2) is not supplied with
the AN/VDR-2 or the installation kit. Vehicular
power is used to operate the set through a
voltage converter (24V to 7.8V).
2-20

NOTE
When the unit is mounted in a vehicle and
the vehicle is turned off, the power to the
unit is lost. If this condition lasts for more
than 5 minutes, the unit memory is lost.
When memory is lost, the prior
accumulated dose cannot be recalled, and
the alarm set points set previously by the
operator are also lost. Alarm set points will
revert to the points set internally in the
radiacmeter, until the operator sets new
alarm points from the front panel.
If the commander requires that prior
accumulated dose be maintained and the
vehicle is turned off, batteries must be
installed in the radiac set within 5 minutes
from the time the vehicle is turned off. See
paragraph 2-10c(1)for battery replacement
procedure.
2-21

2-6. AUTOMATIC TESTING
DURING OPERATION
In addition to the pre-operational tests described
in paragraph 2-4c, the radiac set tests itself
continuously during operation. These tests check
the main battery condition, counting and timing
sequences, internal circuitry, voltage, and
detectors.
a. LOW-BATTERY INDICATOR
If a low battery condition is detected during these
tests, the /hr sign will be shown flashing on the
display. Approximately 10 hours of useful battery
life remain from the moment the low-battery
indicator is first displayed.
2-22
NOTE
When you see this low-battery display, use
the LIGHT as little as possible and replace
the batteries at the first opportunity (see
para 2-4a).

. GENERAL FAULT INDICATOR
To indicate problems other than low
batteries discovered during automatic
testing, the general fault indicator (flashing
0) is displayed.
If your radiac set displays the general fault
indicator during operation or testing,
immediately turn the unit OFF and send to
organizational maintenance for repair.
2-23

c. DELAYED GENERAL FAULT INDICATOR
If the high-range detector becomes defective, the
general fault indicator (flashing 0) is not
displayed immediately, as in the case of all other
electrical faults. The fault indicator has been
delayed 3 minutes so that the operator has time
to observe the display and perform additional
tests.
If the display alternates between a high and low
reading, as shown below, this can be due to a
defect in the high-range tube, or because the
low-range tube (provided the probe cover is open)
is responding to beta radiation in excess of
5cGy/hr. Because the high-range tube is
insensitive to beta radiation, the alternating highand
low-range readings will be normal in this
case.
While the alternating indication is displayed, the
operator should close the probe cover to shield
the low-range tube from beta radiation. If the
alternating indication no longer occurs, no fault
exists. If it continues, the high-range tube is
defective and the radiac set should be referred to
organizational maintenance.
2-24

2-7. NORMAL OPERATING PROCEDURES
a. READ DOSE RATE
NOTE
All you have to do to read dose rate is turn
the unit ON. After any operation, the
display always returns to dose rate.
Set PWR switch to ON.
NOTE
Emission from radioactive materials is
random; it does not occur at a uniform rate.
This causes fluctuations in the readings
displayed by the radiac set.
2-25

. ILLUMINATE OR DARKEN DISPLAY
CAUTION
Over-use of the display light will drain the
batteries.
With PWR switch ON, turn light ON (up) or
OFF (down).
c. READ ACCUMULATED DOSE
With PWR switch ON, press and hold ACCUM
DOSE button to read accumulated dose, then
release button.
2-26

d. CLEAR ACCUMULATED DOSE
(1) Press and hold ACCUM DOSE and DOSE
PER HR buttons
(2)
With both these buttons down, press and
hold CLR/TEST button
2-27

While all three buttons are down, the
previous accumulated dose clears. All three
buttons must be held until display reads:
When the three buttons are released the
display will show dose rate.
e. DISPLAY DOSE RATE ALARM SET POINT
(1)
(2)
(3)
Press and hold DOSE PER HR button
With button pressed, press and hold
CLR/TEST button until alarm set point
for dose rate is displayed in a flashing
mode.
Release both buttons.
2-28

While both buttons are released, display
flashes the dose rate alarm set point shown
above for 10 seconds, then reverts to
normal operation and displays dose rate.
f. DISPLAY ACCUMULATED DOSE ALARM
SET POINT
(1)
(2)
(3)
Press and hold ACCUM DOSE button.
While holding button down, press and hold
CLR/TEST button until the accumulated
dose set point is displayed in a flashing
mode.
Release both buttons.
2-29

The display flashes the accumulated dose
alarm set point shown above for 10
seconds, then reverts to dose rate.
g. TO SET ALARM MODE
(1) Set ALM switch to AUD (up) for audio
alarm.
Alarm sounds when the dose rate or
accumulated dose points are exceeded, or
when a fault occurs.
(2) Set ALM switch to VIS (down) for visual
alarm.
2-30

Appropriate RATE or DOSE light flashes
when the alarm set point is exceeded or
when a fault occurs.
(3)
Set ALM switch to OFF (center) for no
alarm.
h. SET DOSE RATE ALARM
Setting the dose rate alarm set point involves
entering the proper decimal point, range unit,
(µGy/hr, cGy/hr, or Gy/hr), and first, second,
and third digits into the radiacmeter memory.
NOTE
Read each of the steps in this procedure
before trying to set the dose rate alarm. For
the example below, a previous setting of
1.00 cGy/hr is changed to 12.5 cGy/hr.
(1) SETTING DECIMAL POINTS AND UNITS
2-31

(a)
(b)
Press and hold DOSE PER HR button
While still holding the DOSE PER HR
button, press and hold CLR/TEST until
previous dose rate alarm set point is
displayed in a flashing mode, then release
both buttons.
(c)
Within 10 seconds, press and hold
CLR/TEST button again until only
decimal point and unit indicator are
flashing. Release CLR/TEST button.
Display remains the same as in step 2, but
only decimal point and unit indicator flash:
2-32

(d) While decimal point and unit indicator are
flashing, press and release the DOSE PER
HR button .Repeat this until the desired
decimal point setting and units appear.
(e) When certain that the desired combination
of decimal point location and unit
(µG/hr, cGy/hr, or G/hr) are shown,
press and release CLR/TEST
button.
Decimal point and units are now locked into
set. The display will flash the first digit:
2-33

(2) SETTING FIRST DIGIT
(a)
(b)
Press and release DOSE PER HR button
until desired first digit appears. (The first
digit in the example is the same as the
previous setting, so go to step b.)
When desired first digit appears, press and
release CLR/TEST button .The first digit
is locked into set.
When the first digit has been locked into
the set, the display will flash the second
digit:
2-34

(3) SETTING SECOND DIGIT
(a) Press and release the DOSE PER HR
button Continue pressing and releasing
until the desired second digit appears (2 in
the example).
(b) When the desired digit appears, press and
release CLR/TEST button
The second digit is set and the display
flashes the third digit.
2-35

(4) SETTING THIRD DIGIT
(a)
Press and release DOSE PER HR button
Repeat until desired third digit appears
(5 in the example).
(b) Press and hold CLR/TEST button .The
third digit has been set and the new dose
rate alarm set point is displayed.
When CLR/TEST button is
released, the unit then returns to dose rate.
2-36

i. SET ACCUMULATED DOSE ALARM
SET POINT
To enter the accumulated dose alarm set
point, refer to step h, above, for setting
the dose rate alarm set point, except
substitute the ACCUM DOSE button for
the DOSE PER HR button in each step.
If the ALM switch is on VIS the DOSE
light will flash instead of the RATE light.
NOTE
If the unit is installed in a vehicle and it
is required to set the dose rate and/or dose
alarms for radiation outside the vehicle,
follow the procedures given in paragraphs
2-7h and 2-7i except that the alarm set
point values you set to must be divided by
the attenuation factor assigned to the
vehicle in which the radiac set is installed.
For example, if the radiac set is installed in
an M-1 tank which has an attenuation
factor of 20.0 and you wish to set the dose
rate alarm so that it alarms at an external
2-37

j. READ ATTENUATION FACTOR
NOTE
The attenuation factor is different for
different vehicles.
M-1
M2/M3
M-60
M-113
M-151
M-577
M-880
M-1008
M-998
20.0
9.10
23.0
3.60
1.30
4.02
2.00
2.00
1.70
These factors are set by organizational
maintenance. If the factor displayed on
the set in your vehicle in the following
operation does not agree with the factor
listed for that type of vehicle, inform
immediate supervisor.
2-38

(1) Press and hold ATTEN button.
(2) While holding ATTEN button, press
CLR/TEST button.
So long as both ATTEN and CLR/TEST
buttons are pressed, the display indicates
the attenuation factor that has been set by
organizational maintenance.
When button is released, unit returns to
dose rate measured at the probe.
2-39

k. READ DOSE RATE OUTSIDE VEHICLE
NOTE
Emission from radioactive materials is
random; it does not occur at a uniform
rate. This causes fluctuations in the
readings displayed by the radiac set.
(1) Press and hold ATTEN button.
(2) Release ATTEN button.
While button is pressed, display shows dose
sensed at the probe mutiplied by the
attenuation factor, as shown above.
When the buttons are released, the display
returns to dose rate at the probe.
2-40

I. TURN UNIT OFF
Set PWR switch to OFF.
Power to the set is turned off, but stored
information, such as accumulated dose and
alarm set points, is retained.
NOTE
When batteries are removed from the
radiac set memory is retained for only 5
minutes.
2-8. OPERATION IN UNUSUAL WEATHER
At temperatures below -22°F (-30°C) it takes
somewhat longer for characters to form on the
display. The radiac set automatically corrects for
this delay by sensing temperatures below -22°F (-
30°C) and increasing the display time from every
2 seconds to every 5 seconds. Operation of the
set is normal otherwise.
2-41

2-9. OPERATION INSIDE SHELTERS
When monitoring inside shelters, fortifications,
etc., (indirect technique) where radiation is
attenuated when it reaches the probe, preoperational
tests are performed in accordance
with paragraph 2-4c, and normal operation is the
same as if the set was vehicle mounted (see
paragraph 2-7, procedures i and j).
Your unit commander determines the attenuating
factor for the type of shelter in accordance with
FM 3-3 and organizational maintenance sets the
factor.
2-10. EMERGENCY PROCEDURES
a. MISSING MAIN POWER BATTERIES
If the low-battery indicator comes on and three
fresh batteries are not available, the set will
operate on two or a single battery, if necessary.
However, operation with less than three batteries
considerably shortens battery life. If operating on
less than three batteries, use the LIGHT as little
as possible and replace batteries at the first
opportunity (see paragraph 2-4a).
b. MEMORY LOSS
Memory may be lost due to depleted batteries or
when batteries are removed from the radiac set
for more than 5 minutes. When this occurs and
fresh batteries are installed, the number 8 will
appear on the display during turn-on for about 2
seconds and the alarm will sound if the ALM
switch is set to AUD.
2-42

When this condition occurs accumulated dose
and alarm set points will be lost and cannot be
recalled. The operator can, however, reset new
alarm points (see 2-7h and 2-7i).
If you do not reset the alarm points, the set
responds with audible or visual alarm at 1.00
cGy/hr. for dose rate and 1.20 cGy. for
accumulated dose. (These points are set
internally and cannot be changed by the
operator.)
c. LOSS OF VEHICLE POWER
During vehicle-mounted operations, the batteries
are removed from the set and power is derived
from the vehicle-power supply (see paragraph 2-
4a). If this supply does not operate or fails for any
reason, the radiac set will not function.
If you are certain that any apparent failure of the
radiac set is caused by loss of vehicle power,
operation can be partially restored to the set by
disconnecting it from vehicle power and installing
batteries. Under this condition the set works
properly except for the intercom alarm and NBC
(Nuclear/Biological/Chemical) system alarm,
which do not function without vehicle power.
Carefully follow the steps below to remove the set
from the mount and install batteries.
(1) EMERGENCY BATTERY INSTALLATION
(a) Be sure PWR switch is set to OFF.
2-43

(b)
(c)
Disconnect VEHICLE POWER PLUG from
VEHICLE POWER CONVERTER
RECEPTACLE.
Loosen (do not remove) RETAINING SCREWS
and raise TOP COVER.
2-44

(d) Disconnect CONVERTER CABLE PLUG
from receptacle.
(e) Install batteries (see paragraph 2-4a,
and connect receptacle cap.
2-45

(f)
Position coil cord connecting the probe
to the radiacmeter to the back of the unit
through the opening between the top
cover and shelf.
(g)
Position radiacmeter squarely on shelf
above probe and center between LOCKING
LUGS.
2-46

(h) Close TOP COVER to position radiacmeter
against POSITIONING TAB.
(i) Tighten the two RETAINING SCREWS.
(j) Perform operating tests (para 2-4d).
(k) At completion of mission, notify organizational
maintenance of the loss of
vehicle power to radiacmeter.
2-47 /(2-48 Blank)

CHAPTER 3
OPERATOR MAINTENANCE
INSTRUCTIONS
3-1. TROUBLESHOOTING PROCEDURES
This manual cannot cover all the problems that
could happen when using the radiac set. The
troubleshooting chart lists those problems that
are most likely to occur during the operation or
maintenance of the set. If one of these
malfunctions occurs, perform the test or
inspection and corrective action in the order
listed. If a trouble is not listed or it is not
corrected after performing the recommended
corrective action, notify you supervisor. See
Table 3-1.
Table 3-1. TROUBLESHOOTING
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1. DISPLAY IS BLANK WHEN UNIT IS
TURNED ON (NOT VEHICLE
MOUNTED).
Install new batteries (para 24-a).
3-1

Table 3-1. TROUBLESHOOTING
(CONTINUED)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
2. DISPLAY IS BLANK WHEN UNIT IS
TURNED ON (VEHICLE MOUNTED).
Check that all connectors are securely
connected.
Tighten any loose connectors.
3. DISPLAY INDICATES NUMERAL 0
WHEN UNIT IS TURNED ON.
Check that probe is securely connected to
radiacmeter cable.
Connect probe to radiacmeter cable.
4. IMPROPER OR NO ALARM
INDICATIONS DURING NORMAL
OPERATION.
Check alarm set points,
3-2. BATTERY REPLACEMENT.
See paragraph 2-4a.
Reset alarm set points.
3-2

APPENDIX A
REFERENCES
A-1. SCOPE
This appendix lists forms and publications that
are referenced in this manual or that contain
information applicable to the operation and
maintenance of the AN/VDR-2 Radiac Set.
A-2. FORMS
Equipment Inspection and
Maintenance Worksheet . . . . . . . . DA Form 2404
Quality Deficiency
Report . . . . . . . . . . . . . . . . . . . . . . . . Standard Form
368
Recommended Changes to
Equipment Technical
Manuals . . . . . . . . . . . . . . . . . . . . DA Form 2028
A-3. PUBLICATIONS
Consolidated Index of
Army Publications and
Blank Forms . . . . . . . . . . . . . . . . . .DA Pam25-30
Dry Battery Supply Data . . . . . . . . . . . . . . . SB-116
FSC Class 6135; Dry
Battery Management Data . . . . . . . . . . . SB 11-30
A-1

Procedures for Destruction of
Electronic Materiel to
Prevent Enemy Use
(Electronics Command) . . . . . TM 750-244-2
The Army Maintenance
Management System
(TAMMS)
. . . DA PAM 738-750
A-2

APPENDIX B
COMPONENTS OF END ITEM AND
BASIC ISSUE ITEMS LISTS
Section I. INTRODUCTION
B-1. SCOPE.
This appendix lists components of end item and
basic issue items for the AN/VDR-2. This list will
help you keep track of items required for safe and
efficient operation.
B-2. GENERAL
The Compoents of End Item and Basic Issue
Items Lists are divided into the following
sections:
a. Section II. COMPONENTS AND END ITEM.
This listing is for informational purposes only and
is not authority to requisition replacements.
These items are part of the end item, but are
removed and separately packaged for
transportation or shipment. As part of the end
item, these items must be with the end item
whenever it is issued or transferred between
property accounts. Illustrations are furnished to
assist you in identifying the items.
b. Section III. BASIC ISSUE ITEMS (BII).
These are the minimum essential items required
to place the AN/VDR-2 in operation, to operate it,
and to perform emergency repairs. Although
B-1

shipped separately, packaged BII must be with
the AN/VDR-2 during operation and whenever it
is transferred between property accounts. The
illustrations will assist you with hard to identify
items. This manual is your authority to
request/requisition replacement VII, based on
TOE/MTOE authorization of the end item.
B-3. EXPLANATION OF COLUMNS
The following provides explanation of
columns found in 10 tabular listings:
a. Column (1). ILLUSTRATION NUMBER
(ILLUS. NO.). Indicates the number of the
illustration in which the item is shown.
b. Column (2). NATIONAL STOCK NUMBER.
Indicates the national stock number assigned to
the item. The national stock numbers in section
III are used for requisitioning basic issue items.
c. Column (3). DESCRIPTION. Indicates the
national item name and, if required, a minimum
description to identify and locate the item. The
last line for each item indicates the Federal
Supply Code for Manufacturer (FSCM), in
parentheses, followed by the part number.
d. Column (4). UNIT OF MEASURE (U/M).
Indicates the measure used in performing the
actual operation/maintenance function. This
measure is expressed by a two-character
alphabetical abbreviation (e.g., ea, in, pr).
e. Column (5). QUANTITY REQUIRED (QTY
RQR). Indicates the quantity of the item
authorized to be used with/on the equipment.
B-2

Section II. COMPONENTS OF END ITEM.
B-3

(1) (2) (3) (4) (5)
NATIONAL
DESCRIPTION
ILLUS. STOCK FSCM, AND QTY
NO. NUMBER PART NUMBER U/M RQR
1 To be Radiacmeter ea 1
Assigned (80063)
IM-243
VDR-2
2 To be Probe ea 1
assigned (80063)
DT-616/
VDR-2
3 To be Pouch ea 1
assigned (80063)
P/N A3085266
Strap
4 To be (80063) ea 1
assigned
P/N A3085600
B-4

Section III. BASIC ISSUE ITEMS
(1) (2) (3) (4) (5)
NATIONAL DESCRIPTION
ILLUS. STOCK FSCM, AND QTY
NO. NUMBER PART NUMBER U/M RQR
Publication ea 2
TM
11-6665-251-10
NOTE
National stock numbers (NSNs) that are
missing have been applied for and will be
added to this TM by future changes/
revision when they are entered in the
Army Master Data File (AMDF). Until the
NSNs are established and published submit
exception requisitions to: Commander, US
Army Communications - Electronics
Command, and Fort Monmouth. ATTN:
AMSEL-MM-C-BE, Fort Monmouth, New
Jersery 07703-5000 for the part required to
support your equipment.
B-5/(B-6 Blank)

APPENDIX C
EXPENDABLE SUPPLIES AND
MATERIALS LIST
C-1. SCOPE.
Section I. INTRODUCTION
This appendix lists expendable supplies and
materials needed to operate and maintain the
AN/VDR-2. These items are authorized by CTA
50-970, Expendable Items (Except Medical, Class
V, Repair Parts, and Heraldic Items).
C-2. EXPLANATION OF COLUMNS.
a. Column 1. ITEM NUMBER. Assigned to the
entry in the listing and referenced in the
narrative instructions to identify the material (for
example, “Use cleaning compound, Item 4, Appx
C”).
b. Column 2. LEVEL. This column identifies the
lowest level of maintenance that requires the
listed item.
C—Operator Crew
O—Organizational Maintenance
F—Direct Support Maintenance
H—General Support Maintenance
D-Deport Maintenance
c. Column 3. NATIONAL STOCK NUMBER.
The National stock number assigned to the item,
used to request or requisition the item.
C-1

d. Column 4. DESCRIPTION. Indicates the
federal item name and, if required, a description to
identify the item. The last line for each item indicates
the part number followed by the FSCM in
parentheses, if applicable.
e. Column 5. UNIT OF MEASURE (U/M).
Indicates the measure used in performing the actual
maintenance function. This measure is expressed by a
two-character alphabetical abbreviation (e.g., ea, in,
pr). If the unit of measure differs from the unit of
issue, requisition the lowest unit of measure that
satisfies requirements.
Section II. EXPENDABLE SUPPLIES
AND MATERIALS LISTS
(1) (2) (3) (4) (5)
NATIONAL DESCRIPTION
ITEM STOCK FSCM AND
NUMBER LEVEL NUMBER PART NUMBER U/M
1 C NSN Battery, Dry ea
6135-01- BA-3090
063-1978
C-2

THE METRIC SYSTEM AND EQUIVALENTS

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