DATA S H E E T
HIGH POWER TRAVELING WAVE TUBE
FOR GROUND TERMINALS
LD7249 SERIES
14 GHz, 350 W/400 W CW, CONDUCTION COOLING, HIGH POWER GAIN
GENERAL DESCRIPTION
NEC LD7249 series of PPM-focused traveling wave tube are designed for use as final amplifiers in the earth-to-
satellite communications transmitter.
Two models of the LD7249 series are capable of delivering an output power of 350 W and 400 W over the range
of 13.75 to 14.5 GHz and provide a high power gain of more than 47 dB at the rated output power level.
Furthermore, this is of rugged and reliable design offering long-life service.
FEATURES
™
High Power Gain
The power gain is typically 54 dB at the rated output power level.
™
Simple Cooling System
The tube is conduction-cooled so that the cooling system is greatly simplified.
™
PPM Focusing
The tube is PPM (Periodic Permanent Magnet) -focused, eliminating entirely the focusing power supplies and
interlock circuits.
™
Rugged Construction
The tube is designed to be rugged, therefore it is suitable for transportable systems.
™
Long Life and High Stability
The tube employs an advanced impregnated cathode with a low operating temperature for long life.
™
Microdischarge Free
The tube is carefully designed to be free from microdischarge in the electron gun for long term operation,
therefore it is suitable for digital communication service.
For safe use of microwave tubes, refer to NEC document “Safety instructions to all personnel
handling electron tubes” (ET0048EJ∗V∗UM00)
The information in this document is subject to change without notice.
Document No. ET0221EJ5V0DS00 (5th edition)
Date Published August 1999 M
Printed in Japan
©
1997
LD7249 SERIES
GENERAL CHARACTERISTICS
ELECTRICAL
Frequency ……………………………………………… 13.75 to 14.5 GHz
Output Power
LD7249 ……………………………………………… 350 W
LD7249U …………………………………………… 400 W
Heater Voltage ………………………………………… 6.3 V
Heater Current ………………………………………… 1.2 A
Type of Cathode ……………………………………… Indirectly heated, Impregnated
Cathode Warm-up Time …………………………… 180 s
MECHANICAL
Dimensions …………………………………………… See outline
Weight ………………………………………………… 4 kg approx.
Focusing ……………………………………………… Periodic Permanent Magnet
Mounting Position …………………………………… Any
Electrical Connections ……………………………… Flying Leads
Heater, Heater-Cathode,
Helix, Collector-1, Collector-2
and Thermal Protection
RF Connections
Input ………………………………………………… Type SMA Female
Output ……………………………………………… Mates with UBR-120 Flange, Waveguide : WR-75
Cooling ………………………………………………… Conduction
(Optionally, the HV lead out let position can be changeable)
ABSOLUTE RATINGS (Note 1, 2 and 3 )
ELECTRICAL
min.
Heater Voltage ………………………………………
Heater Surge Current
……………………………
Heater Current ………………………………………
Heater Warm-up Time ……………………………
Helix Voltage ………………………………………
Helix Current ………………………………………
Collector-1 Voltage …………………………………
Collector-1 Current …………………………………
Collector-2 Voltage …………………………………
Collector-2 Current …………………………………
Cathode Current ……………………………………
RF Drive Power ……………………………………
Load VSWR …………………………………………
MECHANICAL
Min.
Heat Sink Temperature ……………………………
ENVIRONMENTAL
Min.
Ambient Temperature
Storage ……………………………………………
Operating …………………………………………
–50
–40
+90
+100
˚C
˚C
Max.
Unit
–40
Max.
+115
Unit
°C
6.0
–
1.0
180
8.0
0
4.0
–
2.3
–
200
–
–
max.
6.6
3.0
2.0
–
9.2
10
4.6
180
3.1
290
290
5
1.5 : 1
Unit
V
A
A
s
kV
mA
kV
mA
kV
mA
mA
mW
2
DATA SHEET ET0221EJ5V0DS00
LD7249 SERIES
TYPICAL OPERATION (Note 2, 3 and 5)
LD7249
Frequency ………………………………………………
Output Power …………………………………………
Heater Voltage (Note 4) ………………………………
Heater Current …………………………………………
Helix Voltage ……………………………………………
Helix Current ……………………………………………
Collector-1 Voltage ……………………………………
Collector-1 Current ……………………………………
Collector-2 Voltage ……………………………………
Collector-2 Current ……………………………………
Cathode Current ………………………………………
Power Gain
Gain Variation
Gain Slope
AM-PM ConversioN
Less than 100 W ……………………………
at 350 W ………………………………………
3rd Order Intermodulation …………………………
(two equal carriers, 100 W total)
Note 1 :
Absolute rating should not be exceeded under continuous or transient conditions. A single absolute
rating may be the limitation and simultaneous operation at more than one absolute rating may not be
possible.
Note 2 :
The tube body is at ground potential in operation.
Note 3 :
All voltages are referred to the cathode potential except the heater voltage.
Note 4 :
The optimum operating parameters are shown on a test performance sheet for each tube.
Note 5 :
These characteristics and operating values may be changed as a result of additional information or
product improvement. NEC should be consulted before using this information for equipment
design. This data sheet should not be referred to a contractual specification.
0.3
2.5
–23
0.3
2.5
–24
deg./dB
deg./dB
dBc
at 20 W ………………………
at 350 W ………………………
at 20 W ………………………
at 40 W ………………………
14.25
350
6.3
1.2
8.6
1.5
4.3
141
2.7
94
237
62
58
0.86
0.006
LD7249U
14.25
400
6.3
1.2
8.8
2.4
4.4
147
2.8
100
250
58
54
1.02
0.006
Unit
GHz
W
V
A
kV
mA
kV
mA
kV
mA
mA
dB
dB
dB/750MHz
dB/MHz
DATA SHEET ET0221EJ5V0DS00
3
LD7249 SERIES
LD7249 OUTLINE
(Unit in mm)
85 max.
76
±
1
WITH 8. LENGTH 14
(8 SLOTS)
55.9
±
0.8
22.4
±
0.2
47.8
±
0.2
77.2
±
1.3
RF OUTPUT
UBR-120 FLANGE
WITH No.6-32 UNC-2B
THREADED HOLES
60
±
0.8
43.5
±
0.3
11.5
±
1
38
±
0.8
73.2
±
0.2
117.6
±
0.2
127
±
0.8
162.1
±
0.2
289.1
±
0.2
225.6
±
0.2
431.8
±
0.8
416.1
±
0.2
352.6
±
0.2
0.1
8
×
φ
4.85
+ 0.0
–
THRU
322.8
±
1.5
175
±
0.8
39.9
±
0.8
No.6-32 UNC-2B
×
9 DEEP
BOTHSIDE
0.1
10
×
φ
5
+ 0.0
THRU
–
RF INPUT
SMA FEMALE
19
±
0.3
38
±
0.3
45.7
±
0.3
54
±
0.3
45.5
±
0.8
BeO
CAUTION
LEBEL
I D E N T I F I C AT I O N
LEBEL
PARAMETER
LEBEL
6
±
0.3
57 max.
LEAD COLOR
BROWN
YELLOW
RED
BLUE
BLACK
BLUE (SLIM CABLE)
GREEN (SLIM CABLE)
LEAD CONECTIONS
HEATER
HEATER-CATHODE
COLLECTOR-1
COLLECTOR-2
HILIX (GROUND)
THERMAL SWITCH-1
THERMAL SWITCH-2
LENGTH
650 mm
650 mm
650 mm
650 mm
650 mm
650 mm
650 mm
4
DATA SHEET ET0221EJ5V0DS00
55.9
±
1
LD7249 SERIES
DATA SHEET ET0221EJ5V0DS00
5
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