LRL 550B-SS User manual

MICROWAVES FOR EVERYONE
3rd edition
I-95 Industrial Park
651 Winks Lane
Bensalem, PA 19020
800.523.3929 • 215.638.1100
LRL Model 550B-SS
Microwave Training Kit
Microwave Training Kit
5 Experiments

2 Microwaves for Everyone | LRL 550B Microwave Training Kit
INITIAL SET-UP PROCEDURES • INVENTORY & SET-UP
COMPLETE PARTS LISTING
1 #503A with
2K25 Klystron
Tube Mount
1 #504 Frequency
Meter
1 #505 Slotted Line
2 #506 Variable
Flap Attenuator
1 #507 Termination
1 #508 Thermistor
Mount
1 #518 Detector
Mount
4 #523
Waveguide
Stands
2 #531 Horn
Antennas
1 #532
Shorting Plate

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Microwaves for Everyone | LRL 550B Microwave Training Kit
Inventory & Set Up The LRL 550B Microwave Student Lab . . . . . . . . . . . . 4
Introduction A Brief Discussion of Transmission Line Theory . . . . . . . . 9
Experiment 1 Measurement of Power. . . . . . . . . . . . . . . . . . . . 15
Experiment 2 Measurement of Standing Wave Ratio . . . . . . . . . . . . 23
Experiment 3 Measurement of Frequency and Wavelength . . . . . . . . 31
Experiment 4 Propagation of Microwaves . . . . . . . . . . . . . . . . . 37
Experiment 5 Microwave Antennas . . . . . . . . . . . . . . . . . . . . . 43
LRL Model 550B-SS
X-Band Microwave Training Kit Frequency Range
X-Band 8.2-12.4 (GHZ)
The System Klystron is tuned to (9.3 GHZ)
CONTENTS

4 Microwaves for Everyone | LRL 550B Microwave Training Kit
INITIAL SET-UP PROCEDURES • INVENTORY & SET-UP
LRL 510A POWER SUPPLY
(thermistor bridge & amplifier)

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Microwaves for Everyone | LRL 550B Microwave Training Kit
LRL 510A POWER SUPPLY
(thermistor bridge & amplifier) PLEASE READ CAUTIONS CAREFULLY
BEFORE CONTINUING
CAUTION 1:
Klystrons get extremely hot when in use and must not
be handled while hot! Serious burns can result.
CAUTION 2:
Klystron mount, power supplies, and Klystron tube
plate caps have high voltages present when in use.
Exercise extreme CAUTION!
Shock or death can result.
CAUTION 3:
R-F power levels in this kit are not harmful, but a
human eye may be damaged by low levels of
radiation.
Do not look into any waveguide at any time when
units are on.

6 Microwaves for Everyone | LRL 550B Microwave Training Kit
INITIAL SET-UP PROCEDURES • INVENTORY & SET-UP
The following steps will help you test your new 510A Solid State Power Supply to make
sure it is fully operational and ready for use. It also will give you the opportunity to
operate and become familiar with the entire system before attempting the experiments
listed in this manual.
Equipment & Components
• 510A Power Supply
• 503A Klystron Mount - with 2k25 Klystron installed.
• 506 Flap Attenuator
• 518 Crystal Detector
• 508 Thermistor Mount
• 515 24" BNC Cables (2)
• 523 Waveguide Stands (2)
Part 1 • Control Settings
Set switches and controls on 510A as follows:
1. AC Power Switch OFF
2. Speaker Switch ON
3. RF Switch ON
4. Attenuator Switch 0dB
5. Meter Switch POWER
6. VSWR Output Control MAX. COUNTER CLOCKWISE
7. Power Balance Control 12 O’CLOCK
8. Klystron Repeller Control 12 O’CLOCK
Part 2 •Waveguide Component Assembly Procedure
1. Connect 503A Klystron Tube Mount to left side of 506 Variable Flap Attenuator.
2. Connect right side of 506 Variable Flap Attenuator to left side of 518 Detector
Mount with the BNC Connector in the UP position.
3. Connect right side of 518 Detector Mount to the 508 Thermistor Mount with the
BNC Connector in the UP position.
4. Using BNC Cable, connect 518 Detector Mount to VSWR input connector located
on right side of 510A Power Supply.
5. Using second BNC Cable, connect 508 Thermistor Mount to POWER input
connector located at center of 510A Power Supply.
INITIAL SET-UP PROCEDURES

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Microwaves for Everyone | LRL 550B Microwave Training Kit
6. Insert 8-Prong Plug from 503A Klystron Mount into socket located on left side of
510A Power Supply.
7. Place a 523 Waveguide Stand under each side of Test Assembly, and adjust each
stand until the assembly is elevated in a stable position.
Part 3 • Operation and Checkout
1. Turn AC POWER switch ON.
2. Turn 506 Flap Attenuator to 24dB.
3. Observe meter and adjust POWER BALANCE knob to obtain a zero meter
reading. Turning knob clockwise increases meter reading; counter-clockwise
deceases reading.
4. Allow 3-5 minutes warm-up at this time.
5. Readjust POWER BALANCE knob to compensate for drift if necessary.
NOTE: The meter reading must be at zero to progress further.
6. Set Variable Flap Attenuator to 0dB.
7. Slowly turn KLYSTRON REPELLER knob clockwise and stop when you get a peak
reading on the meter. (Normally about 2 o’clock). NOTE: Adjust Variable Flap
Attenuator as needed to keep meter level between 70% and 100%.
8. Turn METER knob to VSWR position.
9. Fine tune KLYSTRON REPELLER knob as needed to obtain a stable, peak meter
reading. NOTE: This reading should be between 50% and 100% and must be stable. If not,
adjust VSWR OUTPUT knob on right side of 510A Power Supply.
10. Turn METER knob to KLYSTRON position.
11. Remove BNC Cable from VSWR Input Connector at right side of 510A Power
Supply and reconnect cable to KLYSTRON connector on left side of 510A Power
Supply.
12. Adjust Variable Flap Attenuator as needed to attain a peak meter reading. DO NOT
exceed a 100% reading on the meter.
13. Record meter reading and Variable Flap Attenuator level as your Klystron life
reading. NOTE: You can compare this reading to current readings anytime in the future to
determine the condition of the Klystron tube.
14. You have now successfully operated and checked out your Microwave Trainer. It is
important that you turn off the Trainer properly as described below.
Part 4 • Shut Down Procedure
1. Turn off AC POWER switch located on right side of 510A Power Supply.
2. Unplug 510A Power Supply from 115AC Power Source.
3. Wait for Klystron Tube to cool down (minimum of 10 minutes).
4. Disconnect all cables and disassemble waveguide components.

8 Microwaves for Everyone | LRL 550B Microwave Training Kit
introdUCtion – Let’S tALK ABoUt trAnSMiSSion LineS
Transmission lines come in a variety of physical types – coaxial, parallel conductors, and
waveguide are the most common. No matter which type we use, there are four elements
that inuence any physical transmission line:
A. Series inductance: L
B. Series resistance: R
C. Shunt or parallel capacitance: C
D. Shunt or parallel conductance: G
First, let us consider how a unit length of line is represented by Figure 1.1.
Figure 1.1 Unit Length of Transmission Line
The four different elements are represented by the fractional distribution along the entire
length of the line. If the line is to be satisfactory for practical use, it must remain
fractional proportional for any length – long or short. Once this principle is understood,
we can now use the simplied circuit diagram in Figure 1.2.
Figure 1.2 Simplied Unit Length of Transmission Line
INTRODUCTION

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Microwaves for Everyone | LRL 550B Microwave Training Kit
The most widely used unit of measurement for transmission lines is the meter. This
should come as no surprise to you because wavelength and frequency have been
expressed through this unit of measure since the very start of microwave technology.
The expressions of L, R, C, and Gare representative of one unit length of transmission
line dx. When unit lengths appear as two or more lengths, they can be seen as depicted
in Figure 1.3.
Figure 1.3 Several Unit Lengths of Transmission Line
However, the importance of fractional proportionality along any length of line may be
described simply as shown in Figure 1.2. If we apply a voltage ebetween the input
conductors shown in Figure 1.2 and the voltage varies at the rate de/dt, the shunt
current, di per unit length of dx equals the sum of the capacitive current and the
conductive current:
Consequently, the shunt current represents the way in which the input current i is able to
change in a unit length dx Therefore:
When the input voltage eis changing with time, the current will follow. This current
change can be shown as di/dt. The current change causes the series voltage to change
along dx and can be expressed as:
These equations are usually most helpful when a general approach (Fig. 1.1) to trans-
mission lines is desired. However, with most applications, a general approach is not
necessary. In practical use, a short transmission line is utilized, and the line is said to be
“lossless” there by simplifying our analysis even further. The application circuit is shown
in Figure 1.4:
dis
dx
de
dt
=EG+C
and
di
dx
dis
dx
+= 0 ( )
di
dx
de
dt
= - eG+ C
de
dx
di
dt
= - iR+ L
( )

10 Microwaves for Everyone | LRL 550B Microwave Training Kit
introdUCtion – Let’S tALK ABoUt trAnSMiSSion LineS
Figure 1.4 Lossless Transmission Line
In Figure 1.5, we will examine this line as a number of T sections connected together to
represent the line.
Figure 1.5 Sectioned Lossless Line
When we close “s1”, a signal travels through the line. The energy Qtaken from the signal
source is: Q = it where t is the time of current ow. As the signal ows down the line, its
energy will be stored in the capacitors. So any single section is Q = Ce. If capacity Cand
voltage eare shown, it follows that it = Ce. Once C1has fully charged, C2is still at zero
charge and the inductance Lbetween them has a voltage equal to e. Therefore:
Simplifying this relationship produces:
If we divide:
di
dt
e = L
et = Li
et
it =Li
Ce