Telewave 44L1, 44L1P User Manual

Model 44L1/L1P

BROADBAND RF
WATT METER

OPERATION MANUAL

®

Telewave, Inc.

Model 44L1/L1P

MODEL 44L1/L1P BROADBAND RF WATTMETER

DESCRIPTION AND OPERATION

CONTENTS PAGE

1. SPECIFICATIONS 2

2. GENERAL DESCRIPTION 3

3. PHYSICAL DESCRIPTION 5

4. FUNCTIONAL DESCRIPTION
Schematic and Parts List 6

Functional Description 7
Accessory List 8

5. OPERATION
Unpacking and Connections 9

Power Measurements 10
VSWR Calculations 11
True Power at Load Calculation 11
Directivity and Insertion Error 12

6. MAINTENANCE

Warranty Service and Calibration 13
Parts Location 14
Calibration / Adjustment Procedure 15

7. REFERENCE
VSWR Nomograph 17

Jumper Cable Cutting Chart 18

Telewave, Inc. • 660 Giguere Court • San Jose, CA 95133

1-800-331-3396 • 408-929-4400 • www.telewave.com

TWDS-8011 Rev. 3/11 • All Contents © 2011 Telewave, Inc.

Page 1

Telewave, Inc.
Model 44L1/L1P

1 SPECIFICATIONS

1.01 Table 1-1 lists specications for the Telewave Model 44L1/L1P

Broadband RF Wattmeter. These are provided to assist the user in
formulating acceptance criteria, determining applications, and for
periodic recalibration of the instrument. Minor deviations from
these specications which do not affect performance of the Model
44L1/L1P Wattmeter should not be considered a warranty issue.

Table 1-1: Model 44L1/L1P RF Wattmeter Specications

Parameter Characteristics

Frequency Range
Accuracy

2 to 200 MHz
± 7 percent of full scale
(Specied with N connectors only)

Power Ranges 5, 15, 50, 150 and 500 Watts

Primary Line Impedance

VSWR
Insertion Loss

50 Ohms nominal

1.1 maximum

0.1 dB maximum

RF Sample Port (44L1P) -40 dB +/- 2 dB

RF Connectors

Standard
Optional

QC - “Quick-Change” type
N-Female
UHF, BNC, TNC, 7-16 DIN M/F

Dimensions

Height
Width
Depth
Weight

6.625 in. (16.83 cm)
4 in. (10.16 cm)

3.25 in. (8.26 cm)
3 lb. (1.36 kg)

Page 2

Telewave, Inc.

Model 44L1/L1P

2 GENERAL DESCRIPTION

2.01 This manual provides the physical and functional description and

operating theory necessary for effective use of the Telewave Model
44L1/L1P Broadband Radio Frequency (RF) Wattmeter. Its features
include:

• Displays ve power ranges

• Measures 1 to 500 watts

• Does not require inserts

• Does not require band switching

• Fully operable in freezing conditions

• Provides 5 watts full scale range

• Interchangeable connectors (QC)

• Lightweight, rugged and easy to carry

• -40 dB RF sampling port (Model 44L1P)

2.02 The instrument integrates two broadband directional couplers for

measuring incident and reected power, ranging, calibration and
display. The wide coverage and dynamic range of this instrument

eliminates any inserts or band switching. A 20 uA taut band me-

ter movement is used to display the measured power, providing the

measurement accuracy necessary to tune low power portable trans-

mitters.

2.03 A convenient, easy to read, voltage standing wave ratio (VSWR)

chart is provided on the rear of the instrument for determining
VSWR from the measured incident and reected power levels. The
instrument is designed for rugged eld use and is housed in a diecast
metal case with a leather carrying strap. The measurement circuits
in the wattmeter are driven directly by the current developed in the
coupler, making it unnecessary to supply AC power or batteries. A
carrying case (Model TC44) is available as an option. The Model

44L1/L1P is ideally suited for mobile, marine, and aircraft applica-

tions as well as base stations.

Page 3

Telewave, Inc.
Model 44L1/L1P

1

2

3

4

5

7

6

8

9

Figure 2-1: Model 44L1/L1P

Broadband RF Wattmeter

Controls and Indicators

Page 4

Telewave, Inc.

Model 44L1/L1P

3 PHYSICAL DESCRIPTION

3.01 The controls and indicators of the Model 44L1/L1P Broadband RF

Wattmeter are illustrated in Figure 2-1, and the functions of these
elements are described in Table 3-1.

Table 3-1 : Model 44L1/L1P Description

Key Item Description

1 Carry Strap For carrying or hanging the instrument.

2 Identication Label

Contains model and serial number of the
instrument.

3 Meter Displays measured power.

4 Sample Port

Connection point for external measure-

ment or signal injection (Model 44L1P).

Connection point for the RF source, such

5 Input Connector

as an RF power amplier or transmitter.
Mates with Type N or UHF connector
(typical).

Connection for the RF load, such as an an-

6 Output Connector

tenna or dummy load. Mates with Type N
or UHF connector (typ.)

(1) OFF – Transit. Provides protection

for meter during instrument

7 Mode Switch

(2) FWD – Displays forward or incident

movement.

power.

(3) REV – Displays the reected power.

8 Power Range Switch Selects one of 5 full scale power ranges.

9 VSWR Chart

Provides a method to calculate VSWR
from the measured forward and reected
power.

Page 5