Tegam 1806 Instruction Manual

TEGAM Inc.

Model 1806

Dual Type IV Power Meter

MODEL 1806

Instruction Manual

PN# IM140-CD

Publication Date October 2011

REV. J

©1999, TEGAM, Inc.All rights reserved.

NOTE: This user’s manual was as current as possible when this product was manufactured. However,
products are constantly being updated and improved. Because of this, some differences may occur between
the descriptions in this manual and the product received. Please refer to www.tegam.com
of this manual.

for future updates

i

Table of Contents

SECTION I

GENERAL INFORMATION

Scope of Manual .......................................................................................................................................... 1-1

Purpose and Use of Equipment ................................................................................................................... 1-1

Specifications ........................................................................................................................................... 1-1

Items Supplied ........................................................................................................................................... 1-2

SECTION II

INSTALLATION

Unpacking and Inspection ........................................................................................................................... 2-1

Preparation for Reshipment or Storage ........................................................................................................ 2-1

Power, Environmental, and Mounting Requirements .................................................................................. 2-1

Installation ........................................................................................................................................... 2-2

Power Input Connector and Voltage Selector/Fuse Assembly (XF1) ........................................... 2-2

AC Power Input Connector ................................................................................................ 2-2

Voltage Selector/Fuse Subassembly .................................................................................. 2-2

Selection of Proper Fuse/Circuit Board for XF1 ............................................................... 2-2

SECTION III

OPERATION

General Operating Considerations ............................................................................................................... 3-1

Front Panel Meters, Indicators, Switches and Connectors .......................................................................... 3-1

Front Panel Connectors ................................................................................................................. 3-1

BOLOMETER Mount Bias Connectors (TP3 and TP4) .................................................... 3-1

Mount SENSE Lead Connectors (TP1 and TP2) ............................................................... 3-1

TEMPERATURE CONTROL Connector (J5) .................................................................. 3-1

VOLTMETER Connectors (TP5 and TP6) ....................................................................... 3-3

Front Panel Meters ........................................................................................................................ 3-3

BOLOMETER Current Meter (M1) .................................................................................. 3-3

TEMPERATURE CONTROL Meter (M2) ....................................................................... 3-3

Front Panel Indicators ................................................................................................................... 3-3

ON Indicator (DS1) ........................................................................................................... 3-3

STANDBY Indicator (DS2) .............................................................................................. 3-3

100-Ohm Operational Indicator (DS4) .............................................................................. 3-3

200-Ohm Operational Indicator (DS5) .............................................................................. 3-3

ERROR Indicator (DS3) .................................................................................................... 3-4

Model 1806 Switches .................................................................................................................... 3-4

Power Switch (S1) ............................................................................................................. 3-4

100/200-Ohm OPERATING RESISTANCE Switch (S2) ................................................ 3-4

FLOAT/GROUND Switch (S3) ........................................................................................ 3-4

RF Power Level Measurement .................................................................................................................... 3-4

RF Power Measurement Wi th DVM Only .................................................................................... 3-5

RF Power Measurement With DVM and Reference Voltage Generator ....................................... 3-5

SECTION IV

PRINCIPLES OF OPERATION

Introduction ........................................................................................................................................... 4-1

Principle of DC Substitution ....................................................................................................................... 4-1

Precision Power Measurement System ........................................................................................................ 4-1

Self-Balancing Bridge Circuits .................................................................................................................... 4-2

ii

Power Measurements .................................................................................................................... 4-3

RF Power Level Calculation .............................................................................................. 4-4

Controlli ng Thermisto r Mount Int ernal Te mperature .................................................................................. 4-4

Temperature Control Board .......................................................................................................... 4-5

Model 1806 Power Supply .......................................................................................................................... 4-5

Power Supply Electrical Confi guration ......................................................................................... 4-5

Power Supply Application, Transformation, and Isolation ........................................................... 4-5

Motherboard ........................................................................................................................................... 4-6

Front Panel PC Board .................................................................................................................................. 4-6

Measurements Using a Reference Voltage Source ...................................................................................... 4-6

Precision Measurement System Errors ........................................................................................................ 4-7

Calculating Model 1806 Accuracies ............................................................................................................ 4-8

SECTION V

MAINTENANCE

Introduction .......................................................................................................................................... 5-1

Preventive Maintenance ............................................................................................................................. 5-1

Troubleshooting Procedures ........................................................................................................................ 5-1

Specification Tests ........................................................................................................................ 5-1

Power-Up Operational Test ............................................................................................... 5-2

Bolometer Current Meter Test ........................................................................................... 5-3

Bridge Noise Test .............................................................................................................. 5-4

Bridge Balance Test ........................................................................................................... 5-4

Temperature Control ..................................................................................................................... 5-5

Corrective Maintenance and Recalibration ................................................................................................. 5-6

Initial Setup ................................................................................................................................... 5-6

Power Supply Assembly Test and Recalibration .......................................................................... 5-7

Bridge Board Circuitry Test and Recalibration ............................................................................. 5-8

Bolometer Current Meter Cali bration ................................................................................ 5-8

Calibration of Internal Resistance ...................................................................................... 5-9

Bridge Circuit Amplifier Gain Test ................................................................................... 5-9

Factory Maintenance ................................................................................................................................. 5-10

List of Illustrations

Model 1806 Dual Type IV Power Meter .................................................................................................... 1-1

Model 1806 Dimensions (Top/Front View) ................................................................................................ 1-3

Model 1806 Dual Type IV Power Meter Rear Panel Voltage Selector/Fuse Assembly.............................. 2-3

Model 1806 Operational Voltage Selection Process ................................................................................... 2-4

Model 1806 Dual Type IV Power Meter Front Panel Meters, Indicators, Switc hes and Connectors.......... 3-2

Location of Digital Voltmeter in T ypical Test Configuration ..................................................................... 3-5

Location of Reference Voltage Generator in Typical Test Configuration ................................................... 3-6

Functional Block Diagram of Precision Power Measurement System ........................................................ 4-2

Simplified Schematic of Precision Power Measurement System ................................................................ 4-3

Simplified Schematic of Model 1806 Temperature Control Board ............................................................. 4-4

Use of Reference Voltage Generator in Typical Test Configuration ........................................................... 4-6

Graph of Typical Bridge Errors With and Without Reference Voltage Generator ...................................... 4-7

Power-Up Ope rational Test Configuration .................................................................................................. 5-2

Bolometer Current Meter Test Configuration ............................................................................................. 5-3

Bridge No ise Test Configuration ................................................................................................................. 5-4

Bridge Balance Test Configuration ............................................................................................................. 5-5

Initial Test and Calibration Configuration ................................................................................................... 5-6

iii

LIST OF TABLES

Model 1806 Dual Type IV Power Meter Specifications ............................................................................. 1-2

Model 1806 Line-Voltage Fuse Requirements ............................................................................................ 2-2

Comparison of Voltmeter Errors When Reference Voltage Generator Is and Is Not Used ......................... 4-8

Required Test and Calibration E quipment .................................................................................................. 5-1

Power Supp ly Line Regulation Test ing ....................................................................................................... 5-8

iv

Instruction Manual Section I

1-1

Dual Type IV Power Meter, Model 1806 General Information

SECTION I GENERAL INFORMATION

SCOPE OF MANUAL

This manual contains operation and maintenance information for the TEGAM Model 1806
Dual Type IV Power Meter shown in Figure 1-1. This information is in five sections that
outline general information, installation, operation, principles of operation and maintenance.
Discussions throughout this manual concerning use of the Model 1806 treat it as a stand-alone
item. The TEGAM System IIA Automatic Power Meter Calibration System manual contains
information for use, operational role, and cabling of the Model 1806 within a power sensor
calibration system.

Figure 1-1 Model 1806 Dual Type IV Power Meter

PURPOSE AND USE OF EQUIPMENT

The TEGAM Model 1806, in conjunction with an external thermistor mount and a digital
voltmeter (DVM), forms a precision power measurement system that measures microwave
power within the frequency bandwidth of the thermistor mount. The primary application of
this system is for power sensor calibration. The Model 1806 contains two Type IV Bridge
circuits and two thermistor mount temperature controllers. Each Type IV Bridge circuit
operates at a dc resistance of either 100 or 200 ohms which is front-panel selectable. A
complete power measurement system includes an accurate DVM and some means of offsetting
the DVM to measure small voltage changes more accurately. This offsetting voltage source or
reference voltage generator (RVG) becomes increasingly important when measuring power
levels below a few milliwatts. The Model 1806 is designed for use with a temperature­stabilized thermistor mount (100 or 200 ohms) and a DVM with a 6.5 digit, or higher,
resolution.

The Model 1806 contains two self-balancing Type IV Bridge circuits that pass current through
a bolometer mount while sensing the voltage across the mount which defines the resistance of
the bolometer at its dc terminals. This process eliminates lead errors associated with
Wheatstone Bridges. Therefore, the Model 1806 suits applications such as power
measurement and insertion loss measurement applications, requiring high accuracy and
computer control.

The role of the Model 1806 within the TEGAM System IIA Automatic Power Meter
Calibration System is to measure precisely RF and microwave power applied to terminating
standards in order to transfer the calibration factor of one standard to another. The System IIA
is an IEEE Bus compatible system designed to calibrate feedthrough and terminating power
sensors in the .01 to 18.0 GHz frequency range.

SPECIFICATIONS

Table 1-1 contains the electrical, physical, and environmental specifications for the
Model 1806. Figure 1-2 contains an outline drawing and design dimensions.

Instruction Manual Section I

1-2

RF Power Measurement Range:

10 W to 25 mW

Substitution Bridge Accuracy:

0.003%

Power Measurement Accuracy:

0.03% + 2W when using an HP 3458A Voltmeter

Bias Power Temperature
Sensitivity:

2 W/C/hr

Ambient Temperature Dynamic
Range:

+12C to + 32C
(54°F to 90°F)

Mount Warm-up Time:

2 hrs. to achieve + 60°C (140°F) nominal operating
temperature

Loop Gain:

80 dB minimum

Open Loop Frequency Response:

0.1 Hz

Thermistor Mount Temperature
Control Indicator Operating
Range:

Temperature meter with marked operating point
Bolometer Mount Bias Current
Indicator Resolution:

0.1 mA
Power Requirements:

100/120/220/240 VAC, (+5%, -10%) 25W, 48-62 Hz

Dimensions:

18.35 in. (466.1 mm) L x 17.05 in. (433.1 mm) W x 5.80 in
(147.3 mm) H

Constructions:

Cabinet or standard rack mount

Weight:

Net: 16 lbs. (7.26 kg)
Shipping: 20 lbs. (9.07 kg)

Dual Type IV Power Meter, Model 1806 General Information

Table 1-1 Model 1806 Dual Type IV Power Meter Specifications

ITEMS SUPPLIED

The following items are supplied with the TEGAM Model 1806 Dual Type IV Power Meter:

1. Assembly AC Power Cable, P/N 068-21, 1 ea.

2. Assembly Temperature Control Cable, P/N 138-477, 2 ea.

3. Assembly Mount Bias Cables, P/N 138-526, 2 sets ea.

4. Model 1806 Instruction Manual (IM-140), 1 ea.

5. Shorting Link, P/N 138-495, 4 ea. (installed on front panel)

OPTIONAL ACCESSORIES

The following items can be purchased separately and are needed to perform
calibration service on the 1806.

1. Assembly Extender Board, P/N 138-439, 1 ea.

2. Printed Circuit Card Pullers, P/N 139-1141, 2 ea.

Instruction Manual Section I

1-3

18.35

(466.1mm)

CONTROL

TEMPERATURE

ERROR

100

OPERATING
RESISTANCE

200

VOLTMETERSENSE

BOLOMETER

CURRENT

BOLOMETER

O

I

POWER

OFF

ON

STAND BY

VOLTMETER

100

ERROR

CURRENT

BOLOMETER

RESISTANCE

OPERATING

200

BOLOMETER

SENSE

TEMPERATURE

CONTROL

Dual Type IV Power Meter, Model 1806 General Information

Figure 1-2 Model 1806 Dimensions (Top/Front)

Instruction Manual Section I

1-4

Dual Type IV Power Meter, Model 1806 General Information

Instruction Manual Section II

2-1

Dual Type IV Power Meter, Model 1806 Installation

SECTION II INSTALLATION

UNPACKING AND INSPECTION

TEGAM ships the Model 1806 cushioned between molded-in-place expanded plastic pads in a
double-walled carton. Upon unpacking the equipment, retain the shipping container and
packing material until the equipment has been thoroughly inspected and it is ensured that
reshipment is not necessary. Perform the following initial inspection:

a. Carefully look at the outside of the shipping container for discoloration, stains, charring,

or other signs of exposure to excessive heat, moisture, or liquid chemicals. Check for any
physical damage to the shipping container such as dents, snags, rips, crushed sections or
areas, or similar signs of excessive shock or careless handling.

b. With the equipment and any accessory package removed from the shipping container,

check each item against the packing list or items supplied list. If any items are missing,
contact the factory or the manufacturer’s local representative.

c. Carefully inspect the equipment looking for dents, deep scratches, damaged or loose

pushbuttons or knobs, or any other signs of physical abuse or careless handling.

If damage is found, forward an immediate request to the delivering carrier to perform an
inspection and prepare a concealed damage report. Do NOT destroy any packing material
until it has been examined by an agent of the carrier. Concurrently, report the nature and
extent of damage to TEGAM giving equipment model and serial numbers, so that necessary
action can be taken. Under U.S. Shipping regulations, damage claims must be collected by the
consignee; do NOT return the equipment to TEGAM until a claim for damages has been
established.

PREPARATION FOR RESHIPMENT OR STORAGE

RESHIPMENT

Perform the following procedures when reshipping an instrument or component:

 DO NOT return any instrument or component to TEGAM without receiving prior factory

authorization (RMA Number).

 Use the best available packing materials to protect the instrument during reshipment.

When possible, use original shipping container and packing materials.

a. Wrap the instrument in sturdy paper or plastic;
b. Place the wrapped instrument in a strong shipping container and place a layer of shock-

absorbing material (3/4 inch minimum thickness) around all sides of the unit to provide a
firm cushion and to prevent movement inside the container;

c. If shipping the unit for service, attach a tag to indicate:

1. Model and serial numbers,

2. Service required,

3. Description of malfunction,

4. Return address,

5. Authorization to conduct repairs; and

Thoroughly seal the shipping container and mark it FRAGILE.

STORAGE

Storage of the unit is possible for extended periods without incurring damage to internal
circuitry if the instrument is packaged according to the instructions above. The safe limits for
storage environment are:

Temperature: -67 to + 167 F (-55 to + 75 C)
Humidity: 95%
Altitude: 40,000’ (12,192M)

Instruction Manual Section II

2-2

Dual Type IV Power Meter, Model 1806 Installation

POWER, ENVIRONMENTAL AND MOUNTING REQUIREMENTS

TEGAM supplies a detachable, three-conductor power cord for connecting an ac power
source of 48 to 62 Hz at line voltages of 100, 120, 220, or 240 volts +5%, -10% to the
Model 1806. This ac power source supplies the Model 1806 with all operational power
required. The Model 1806 requires no other external power.

The Model 1806 operates within its specifications at an ambient temperature of +12 C to
+32 C. Operating beyond these limits could affect the accuracy of this unit and damage
internal circuitry.

TEGAM ships the Model 1806 with four plastic feet and a tilt stand mounted on the
bottom of the unit for bench use; however, the Model 1806 is also rack-mountable. To
rack-mount the unit, first remove the four plastic feet and the tilt stand on the bottom of
the unit. Next, remove the rear panel trim and slide the side panels out. Then, remove
the side trim and install rack adapters on the left and right sides of the Model 1806. Re­attach the rear panel trim to the unit while leaving the side panels off. When rack
mounting the unit, ensure access to the rear panel so that rear panel connections can be
made. The unit may now be mounted into a standard rack.

INSTALLATION

Installation of the Model 1806 consists of rack mounting or bench configuring the unit,
selecting the proper line-voltage fuse and circuit board, and connecting the unit to the desired
ac power source that matches the fuse and circuit board.

POWER INPUT CONNECTOR AND VOLTAGE SELECTOR/FUSE ASSEMBLY (XF1)

Assembly XF1 is in the lower right-hand corner of the rear panel of the Model 1806. This
assembly contains a three-prong ac power input connector and a voltage selector circuit
board/fuse assembly. The design of XF1 prevents use of the voltage selector/fuse assembly
while an ac power cord is connected to the ac power input connector. Disconnect the power
cord and slide the protective plastic window to the left to change the line fuse and printed
circuit (PC) board. This arrangement eliminates the possibility of electric shock to operating
personnel.

Power source voltages of sufficient current to constitute a HAZARD to operating
personnel exist at the voltage selection PC board and line fuse. Ensure that the power
cord is DISCONNECTED prior to changing line voltage selection or line fuse.

AC Power Input Connector

This connector, located on the left side of XF1, is a plug-type, prong-insert connector with
three conductors for connection of the 100/120/200/240 volt ac power cord (P/N 068-21) to the
power supply assembly within the Model 1806. Arrangement of the conductors and keying of
the insertion area prevent an incorrect connection. This connector also passes the ground
current of the Model 1806 when the ac power cord is plugged into a grounded wall outlet.
When the wall outlet contains two insertion slots, use a three-prong-to-two-prong adaptor.

Voltage Selector/Fuse Subassembly

The voltage selector/fuse subassembly on the right side of XF1 reconfigures the Model 1806
for different operational voltages. This subassembly contains a line fuse and a voltage selector
PC board. Replacement of the fuse and proper selection of the voltage selector PC board
change the operational power requirement to ac voltages of either 100, 120, 220, or 240 volts
at 48 to 62 Hz. Refer to the following paragraph for the proper fuse/PC board selection.

Selection of Proper Fuse/Circuit Board for XF1

TEGAM ships the Model 1806 configured for 120-volt operation. Table 2-1 lists fuse
requirements for other available operational voltages. Figure 2-2 depicts the procedure,
including outline steps, for removal of the line voltage fuse, selection of the proper line-voltage
PC board, and replacement of the fuse.

Instruction Manual Section II

2-3

Operational Line Voltage

Fuse Requirement

100 volts +5%, -10% at 48 to 62 Hz

0.75 Amp Slo-Blo

120 volts +5%, -10% at 48 to 62 Hz

0.75 Amp Slo-Blo

220 volts +5%, -10% at 48 to 62 Hz

0.4 Amp Slo-Blo

240 volts +5%, -10% at 48 to 62 Hz

0.4 Amp Slo-Blo

Dual Type IV Power Meter, Model 1806 Installation