TELEWAVE 44L1 Manuale utente
Model 44L1/L1P
BROADBAND RF
WATT METER
OPERATION MANUAL
®
Telewave, Inc.
Model 44L1/L1P
Page 1
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 2
Telewave, Inc.
Model 44L1/L1P
1 SPECIFICATIONS
1.01 Table 1-1 lists specications 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 specications 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 Specications
Parameter Characteristics
Frequency Range
Accuracy
2 to 200 MHz
± 7 percent of full scale
(Specied 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)
Telewave, Inc.
Model 44L1/L1P
Page 3
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 reected 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 reected 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 4
Telewave, Inc.
Model 44L1/L1P
1
8
7
6
5
4
3
2
9
Figure 2-1: Model 44L1/L1P
Broadband RF Wattmeter
Controls and Indicators
Telewave, Inc.
Model 44L1/L1P
Page 5
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.
Key Item Description
1Carry Strap For carrying or hanging the instrument.
2Identication 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).
5Input Connector
Connection point for the RF source, such
as an RF power amplier or transmitter.
Mates with Type N or UHF connector
(typical).
6 Output Connector
Connection for the RF load, such as an an-
tenna or dummy load. Mates with Type N
or UHF connector (typ.)
7Mode Switch
(1) OFF – Transit. Provides protection
for meter during instrument
movement.
(2) FWD – Displays forward or incident
power.
(3) REV – Displays the reected power.
8 Power Range Switch Selects one of 5 full scale power ranges.
9VSWR Chart
Provides a method to calculate VSWR
from the measured forward and reected
power.
Table 3-1 : Model 44L1/L1P Description
Page 6
Telewave, Inc.
Model 44L1/L1P
Figure 3-1: Model 44L1/L1PRF Wattmeter Schematic
Table 3-2 : Model 44L1/L1P Parts List
R2
R12
R8
R4
R15
R11
R7
R3
R18
R17
R14
R13
R10
R9
R6
R5
S1
S2
OFF
REVFWD
M1
+-
500
150
50
15
5
500
150
50
15
5
R1
R19 R20
RF
SOURCE RF
LOAD
A1
Dual Directional Coupler
REF DESCRIPTION MFG MFG P/N
M1
MP1
MP2
MP6
MP8
MP9
QC
QC
QC
QC
QC
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
R15
R16
R17
R18
R19
R20
S1, 2
METER: 20 UA
KNOB
SCREW: BUMPER 6-32
STRAP: LEATHER
SCREW: TRUSS HEAD 10-52
SHOCK RING: EDM
N FEMALE CONNECTOR
UHF FEMALE CONNECTOR
BNC FEMALE CONNECTOR
TNC FEMALE CONNECTOR
7-16 DIN FEMALE CONNECTOR
RESISTOR: VAR CC 0.25W 10% 50K OHM
RESISTOR: VAR CC 0.25W 10% 50KOHM
RESISTOR: VAR CC 0.25W 10%50KOHM
RESISTOR: FXD CC 0.50W 5% 7.5K OHM
RESISTOR: FXD CC 0.50W 5% 7.5K OHM
RESISTOR: VAR CC 0.25W 10%50KOHM
RESISTOR: VAR CC 0.25W 10%50KOHM
RESISTOR: FXD CC 0.50W 5% 62K OHM
RESISTOR: FXD CC 0.50W 5% 62K OHM
RESISTOR: VAR CC 0.25W 10%50KOHM
RESISTOR: VAR CC 0.25W 10%100KOHM
RESISTOR: FXD CC 0.50W 5% 130KOHM
RESISTOR: FXD CC 0.50W 5% 130KOHM
RESISTOR: VAR CC 0.25W 10%100KOHM
RESISTOR: VAR CC 0.25W 10%100KOHM
RESISTOR: FXD CC 0.50W 5% 300K OHM
RESISTOR: FXD CC 0.50W 5% 300K OHM
RESISTOR: VAR CC 0.25W 10%100KOHM
RESISTOR: FXD CC 0.25W 5% 51 OHM
RESISTOR: FXD CC 0.25W 5% 51 OHM
SWITCH: ROTARY 2 POLE 5 POS
TRIPLETT
RAYTHEON
TELEWAVE
TELEWAVE
ICO-RALLY
TELEWAVE
TELEWAVE
TELEWAVE
TELEWAVE
TELEWAVE
TELEWAVE
ELECTROSWITCH
7034
MS-91528-1P2B
TB44
HH44
SCR-813
7099
QC44N
QC44S
QC44B
QC44T
QC44D
D3G0205N-4096
R16
Telewave, Inc.
Model 44L1/L1P
Page 7
4 FUNCTIONAL DESCRIPTION
4.01 The Model 44L1/L1P Wattmeter is made up of two major sections.
Refer to the schematic diagram in Figure 3-1 for this description.
(a) A Dual RF Directional Coupler with directivity of greater than
25 dB.
(b) A voltmeter circuit. Five ranges are provided.
4.02 The 50 ohm Dual Directional Coupler A1 samples a small amount
of the incident or forward RF power delivered to the load. The cou-
pler incorporates two RF detectors which produce a DC voltage
proportional to the sampled RF power. A small amount of power
reected from the load is also sampled.
4.03 Mode Switch S1 determines which of these voltages is displayed on
the meter, M1. The RF Power Range Switch S2, selects the appro-
priate range and calibration resistors for the power to be measured.
Each range is provided with an adjustable internal potentiometer for
range calibration.
4.04 Meter M1 displays ve scales which correspond to the RF Power
Range Switch positions. The lower third of the meter scale is shaded
red, alerting the user to switch to a lower power range for improved
accuracy. An OFF position is provided on Mode Switch S1, which
shunts out the meter movement. This provides protection for the
sensitive meter when the instrument is being transported.
4.05 Model 44L1P provides an RF sampling port with an output of -40
dB (+/- 2 dB) below the transitional line level to use for measure-
ment of frequency, spectrum analysis, to inject a signal for measure-
ment of receiver sensitivity, or other applications. The port coupling
is not directional; in a high VSWR system, the sampling port output
will be -40 dB below the total power passing through the instru-
ment.
Page 8
Telewave, Inc.
Model 44L1/L1P
Part Number Description
TC44 Leather carry case with accessory pouch
TWL-35 Coaxial Dry Load - 35 watts
TWL-50 Coaxial Dry Load - 50 watts
TWL-60 Coaxial Dry Load - 60 watts
TWL-75 Coaxial Dry Load - 75 watts
TWL-100 Coaxial Dry Load - 100 watts
TWL-150 Coaxial Dry Bench Load - 150 watts
TWL-300 Coaxial Dry Bench Load - 300 watts
QC44B Quick Change BNC-female connector
QC44D Quick Change 7-16 DIN-female connector
QC44N Quick Change N-female connector
QC44S Quick Change UHF-female connector
QC44T Quick Change TNC-female connector
ANTA-02-5 Jumper - RG-213/U, 5 ft., N-Male
ANTD-03-5 Jumper - RG-142B/U, 5 ft., N-Male
Optional Accessories
4.06 The table below lists the most common accessories for the Model
44L1/L1P Wattmeter. Consult the current price list or our website
for current pricing.
Figure 4-1: Optional TC44 Carrying Case and RF Loads
Telewave, Inc.
Model 44L1/L1P
Page 9
5 OPERATION
Unpacking
5.01 After the Model 44L1/L1P Wattmeter arrives, examine the ship-
ping container for visible loss or damage. Carefully unpack the
wattmeter and examine the exterior for damage.
IMPORTANT
The Model 44L1/L1P Wattmeter is carefully tested, inspected,
and packed before leaving the Telewave factory. Claims for loss
or damage sustained in transit should be made upon the carrier,
NOT TO Telewave, Inc., as follows:
(1) Visible Loss or Damage - Any evidence must be noted on
the freight bill or express delivery sheet. The form required
to le such a claim will be supplied by the carrier.
(2) Concealed Loss or Damage - This damage does not be-
come evident until after the wattmeter is unpacked. When
the damage is discovered, make a written request for in-
spection by the carrier’s agent within fteen (15) days of
the delivery date. File a claim with the carrier.
RF Connections
5.02 The following procedure will assist the user in preparation for
making an RF power measurement. Refer to Figure 2-1.
Step Procedure
1Remove the RF power from the transmission line.
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