DATA S H E E T
Document No. ET0205EJ1V1DS00
Date Published August 1998 M
Printed in Japan
14 GHz, 123 W CW, CONDUCTION COOLING, MINIMUM SIZE
The information in this document is subject to change without notice.
1996
HIGH POWER TRAVELING WAVE TUBE
FOR GROUND TERMINALS
LD7246A
For safe use of microwave tubes, refer to NEC document "Safety instructions to all personnel
handling electron tubes" (ET0048EJ
V
UM00)
GENERAL DESCRIPTION
NEC LD7246A is PPM-focused traveling wave tube designed for use as final amplifier in the earth-to-satellite
communications transmitter.
This is capable of delivering an output power of 130 W over the range of 13.75 to 14.5 GHz.
It provides a high power gain of 53 dB at 123 W output power.
Furthermore, this is of rugged and reliable design offering long-life services.
FEATURES
TM Light weight, Compact and Efficient
The tube has dual-depressed collectors and is designed to operate at high efficiency across wide power
output range. It features state-of the art techniques to optimize size and efficiency.
TM High Power Gain
The power gain is typically 53 dB at 123 W level.
TM Simple Cooling System
The tube is conduction-cooled, so that the cooling system is greatly simplified.
TM PPM Focusing
The tube is PPM (Periodic Permanent Magnet) -focused, eliminating entirely focusing power supplies and inter-
lock circuits.
TM Rugged Construction
The tube is designed to be rugged, therefore it is suitable for transportable systems.
TM Long Life and High Stability
The tube employs an advanced impregnated cathode with a low operating temperature for long life.
TM 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.
2
LD7246A
GENERAL CHARACTERISTICS
ELECTRICAL
Frequency ...................................................... 13.75 to 14.5 GHz
Output Power ................................................ 123 W
Heater Voltage ................................................ 4.5 V
Heater Current ................................................ 1.0 A
Type of Cathode ............................................. Indirectly heated, Impregnated
Cathode Warm-up Time
................................. 180 s
MECHANICAL
Dimensions ................................................... See Outline
Weight ......................................................... 1.3 kg approx.
Focusing
...................................................... Periodic Permanent Magnet
Mounting Position .......................................... Any
Electrical Connections .................................... Flying Leads
Heater, Heater-Cathode,
Helix, Collector-1, Collector-2
RF Connections
Input ......................................................... SMA- Female
Output ...................................................... Mates with UBR-120 Flange
Cooling ......................................................... Conduction
ABSOLUTE RATINGS ( Note 1, 2 and 3 )
ELECTRICAL
Min.
Max.
Unit
Heater Voltage .............................................
4.2
4.8
V
Heater Surge Current
.................................
2.5
A
Heater Current .............................................
1.3
A
Heater Warm-up Time .................................
180
s
Helix Voltage
.............................................
6.0
6.4
kV
Helix Current
.............................................
5.0
mA
Collector-1 Voltage .......................................
3.1
3.3
kV
Collector-2 Voltage .......................................
1.5
1.7
kV
Cathode Current ..........................................
140
mA
RF Drive Power ..........................................
1.0
dBm
Load VSWR ................................................
1.5 : 1
MECHANICAL
Min.
Max.
Unit
Baseplate Temperature
Storage ...................................................
30
+110
C
Operation ................................................
30
+110
C
3
LD7246A
TYPICAL OPERATION (Note 2, 3 and 5)
Unit
Frequency ......................................................
13.75 to 14.5
GHz
Output Power ................................................
130
W
Heater Voltage (Note 4) ....................................
4.5
V
Heater Current ................................................
1
A
Helix Voltage ...................................................
6.2
kV
Helix Current ...................................................
3
mA
Collector Voltage-1 ..........................................
3.2
kV
Collector Current-1 ..........................................
80
mA
Collector Voltage-2 ..........................................
1.6
kV
Collector Current-2 ..........................................
42
mA
Cathode Current .............................................
125
mA
Power Gain
at 6 W ..............................
58
dB
at 130 W ...........................
53
dB
Gain Variation
at 13 W ...........................
2
dB/750 MHz
Gain Slope
at 13 W ...........................
0.03
dB/MHz
AM-PM Conversion at 130 W ...........................
3.5
deg./dB
3rd Order Intermodulation
(two equal carriers, 13 W total) ........................
32
dBc
Efficiency
......................................................
38
%
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 exept 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.
LD7246A
NEC Corporation does not assume any liability for infringement of patents, copyrights or other intellectual
property rights of third parties by or arising from use of a device described herein or any other liability arising
from use of such device. No license, either express, implied or otherwise, is granted under any patents, copy-
rights or other intellectual property rights of NEC Corporation or others.
LD7246A OUTLINE (Unit in mm)
9.6
38
14.25
14.25
42
315
35
50 Max.
RF Out put
Mates With
UBR-120 Flange
RF Input
SMA Female
HV Lead Wires
Length : 300
7
40
30
20
80
90
275
295
230
93
40
34
19
13.21
13.21
38
Output Flange
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