Schwarzbeck FCKL 1528 Technical Document

SCHWARZBECK MESS - ELEKTRONIK
DESCRIPTION, DATA SHEET
9 kHz - 30 MHz
Interference Measuring Receiver
FCKL 1528

Description, Data Sheet FCKL 1528 Page -2
tFrequency range 9 kHz - 30 MHz
t10 Hz - Frequency steps
tConducted interference measurement
with L.I.S.N.
tField strength measurement with
adapter.
tIntegrated power attenuator for
receiver protection.
tOptional high level tracking generator
is ideal to measure Lamp attenuation
acc. to EN 55015.
Also for filter attenuation, free area
attenuation and to drive power
amplifiers.
tManual Operation, semi-automatic
operation with xy-recorder and PC-
control via IEEE-bus using the
Schwarzbeck software.
tFast 100% CISPR Quasipeak, CAV and
CRMS measurement with VARISCAN.
For many decades, most of the
interference measuring receivers were
used in laboratories. They were operated
manually using their front panel. This type
of operation including front panel control
will still be there in the future, but PC-
control gives value added measurement
because of increased speed and better
documentation. The unique r. f. and
analogue circuits of the FCKL 1528 give
precise measurement with or without PC-
control. The receiver comes complete for
EMI-measurement, but can be equipped
with useful options.
Characteristics of the FCKL 1528
Unique R.F. - circuitry
uAttenuator with r.f.-relays uses resistive
Π-attenuators with 1 dB steps. Total
resistive attenuation is 95 dB.
uSwitchable 10 dB high-power-attenua-
tor with 10 W for safe measurement
with L.I.S.N.s up to 4 x 400 A.
u5 Input filters. Shape factors optimised
for EMI - measurement.
uCISPR standard filters with 200 Hz and
9 kHz / - 6 dB. Filters are classic
double tuned band filters.
uIntegrated 25 Hz / 100 Hz Pulse-
standard for CISPR Band A and B
similar to IGLK 2914 for calibration.
Error is compensated by a EPROM list.
uIntegrated (optional) tracking generator
with 120 dBµV(1 V) / 50 Ωfor mea-
surement of Lamp attenuation, filter
attenuation, field attenuation with an-
tennas and amplifier drive.
High precision measurement
uMeter with 2 large scales.
Linear voltage scale with 1 dB-scaling
for the amplitude range
-10 dB / 0 dB centre of meter +6 dB
according to EN 55014 C.2.1.
plus Logarithmic overview
-25 dB / 0dB centre of meter +25 dB
u12 Bit A/D-converter
Easy to use
uFunctional areas of controls and
displays.
uSmall size, moderate weight
uu Rugged Aluminium cabinet
uu Low heat dissipation
uDue to effective shielding no problems
even when used in the shielding room.
Data Interface
IEC-Bus-Interface: Connector 24 sockets
Sub D-Connector 25 sockets
§Supply Voltages d.c. +12 V / -12 V for
auxiliary equipment
§XY-recorder control Frequency Ampli-
tude, Penlift
§Output voltage of active Demodulator
(Envelope) for auxiliary or monitoring
with Oscilloscope
§§ Sub-D-connector 9 sockets for
L.I.S.N-control
BNC-Outputs
§I. F.-Output
§Tracking generator output 120 dBµV
50 Ω(optional)

Description, Data Sheet FCKL 1528 Page -3
Modes of operation
The FCKL 1528 covers the following modes:
wManual operation with manual
frequency tuning and reading the
measurement from the meter.
wSemi-automatic operation using an xy-
recorder for the reading.
wPC-controlled operation via IEEE-bus
with Schwarzbeck Software.
Manual operation
As no other this mode of operation gives
direct access to the receiver without any
collision with PC or software. Especially in
the measuring field outside of a shielding
room, broadcast signals can be identified
using the demodulator/loudspeaker. CW-
signals can be monitored with 0 kHz and
1kHz beat frequency.
Reading can be seen clearly on the meter
which gives perfect reading from narrow
band signals down to single click.
§The meter uses the classic 0 dB centre
of meter scaling for safe measurement
without interpretation.
§The linear scale gives true linear voltage
reading avoiding problems with slow
pulses.
§For any interference signal from
continuous distortion to single click 0 dB
centre of instrument is free of overload
problems. For overview a 50 dB scaling
can be used.
Semi-automatic operation
Spectrums can be recorded when the
receiver is used in the scan mode
together with an xy-recorder.
The time consumption is reduced
substantially, because VARISCAN adjusts
scan speed to the signals ahead.
So spectrum can be scanned directly in
CISPR-Quasipeak to avoid switching
CISPR/Peak. The xy-recorder can be
used in manual tuning mode as well. The
xy-recorder then follows the manual
frequency tuning on the encoder. Doing
so, it is very easy to stop on critical
frequencies to find the maximum signal
strength, which will be kept by the xy-
recorder.
PC-controlled mode
Using a standard PC, a IEEE-card and the
Schwarzbeck software Messbase together
with the FCKL 1528 gives PC-controlled
measurement. Modern PCs offer high
speed and high capacity hard disks which
improve considerably storage and
documentation of measurement.
Primary goal of development was safe
measurement of the complete range of
interference signals keeping the high
standard of manual measurement. This
means that there must be no trade off
considering even slow pulses.
The completely new approach using the
fourth demodulator included in VARISCAN
gives fast Quasipeak, CAV and CRMS
measurement without using the Peak
detector. VARISCAN analyses the signal
ahead before it is really measured.
Practical spectrum often shows amplitude
jitter which could be subject to
misinterpretations using the Peak detector
to decide which signal has to be re-
measured in Quasi-Peak or not.
The second step towards safe
measurement is controlling the receiver by
the limits given in the standards.
Basically autorange can catch any signal,
but there are restrictions when slow
pulses occur.
The way out of the problem is to guide the
receiver along the limits in such a way,
that it is centred in the middle between
noise and overload. Even antenna factors
are included in this strategy.

Description, Data Sheet FCKL 1528 Page -4
SCHWARZBECK MESS - ELEKTRONIK
Messbase-Software for Emission-tests under MS-WINDOWS 95/98/NT/2000/XP
-Easy to learn and to use
-Fast & Reliable with Variscan and Autorange
-High security against overload using mask-guidance
-User editable limits and antenna factors guarantee high flexibility
-Interactive final measurements with automatic test report generation
-Automatic creation and scan of frequency lists
-Free scalable prints
-User definable creation of test reports
-Convenient graphic features and data transfer to other Windows applications
-Marker with integrated final measurement capability
-Subranges reduce measuring time and provide data reduction
-Remote control for LISN or coaxial switching unit included
-Additional IEEE 488-devices can be integrated on request
-Attenuation measurements > 100 dB for site performance checks or insertion loss of filters
-Comparison of two measured diagrams and up to 3 masks simultaneously
-Accelerator keys for frequently used functions speed up operation
-Click measurement with 10 samples per second
-Context sensitive Online Help
-Macros performing up to 32 time-consuming measurements
-Find the Maximum Envelope out of a set of measurements
Hardware - Requirements:
IBM-compatible PC with 80386 and math. Coprocessor 80387 or better, 4 MByte RAM, VGA-Graphics,
min. 10 MByte free space on hard disk, 3.5" floppy disk drive, INES IEEE 488 16- bit interface card.
PCMCIA-card also available for portable Computers.

Description, Data Sheet FCKL 1528 Page -5
FCKL 1528 Technical data
Detectors Peak PK
Average AV
CISPR Quasi-Peak QP
CISPR-Average CAV
CISPR-RMS CRMS
Frequency range 9 kHz-30 MHz
Frequency tuning with encoder wheel
10 Hz-10 kHz,
Display 6digits LED
Software Start- and Stop frequency
random, > 10 Hz, automatic
scanning with graphic.
Frequency error 1*10-5 +-100 Hz
R.F.-Input BNC-connector, 50 Ω
SWR <1,2 for attenuator >10 dB
<2 for attenuator 0 dB
Oscillator voltageon R.F. Input
<30 dBpW for attenuator 0 dB
<20 dBpW for 10 dBpower attenuator
R.F.-Prefiltering 5 Bandpass filters
switched by relays
1 9 kHz - 150 kHz
2 150 kHz - 3 MHz
3 3 MHz - 10 MHz
4 10 MHz - 20 MHz
5 20 MHz - 30 MHz
Calibration
Pulse standard for CISPR 3
Standard 25 Hz, nom. 30 dBµV (25 Hz)
Pulse standard for CISPR 1
Standard 100 Hz, nom. 30 dBµV (100 Hz)
Maximum Input Level
R.F-attenuation 0 dB (no D. C.-isolation)
D.C. 7 V
Sine wave R.F. voltage 130 dBµV (3,16 V)
R.F.-attenuation 10 dB (D. C-isolation)
Spectrum pulse density 96 dBµV/MHz
R.F.-attenuation 10 dB power attenuator
D.C.-voltage 15 V
Sine wave R.F. voltage
continuous 141 dBµV (3 W)
Intermittent 20% on,
Burst<0,5 sec. 143 dBµV (5 W)
Spurious, Large Signal Handling Capability
Image frequency atten. >65 dB / typ. 90 dB
I.F.-isolation >70 dB / typ. 90 dB
Spurious None
Third order Intercept d3
standard setup >25 dBm
(>15 dBm w.o. power attenuator.)
R.F.-feed through
(1 dB error, w.o. receiver frequ.) 10 V/m
I.F. frequencies
range 9 kHz - 150 kHz 1. I.F. 455 kHz
2. I.F. 45 kHz
range 150 kHz - 30 MHz 1. I.F. 40 MHz
2. I.F. 455 kHz
3. I.F. 45 kHz
I.F.-Standard filter bandwidths acc. to CISPR3/1
200 Hz / 9 kHz (-6 dB)
Noise indication (bandwidth 200 Hz)
Average < -30 dBµV
Peak typ. -18 dBµV
CISPR Quasipeak < -30 dBµV
Noise indication (bandwidth 9 kHz)
Average < -14 dBµV
Peak typ. -8 dBµV
CISPR Quasipeak < -14 dBµV
Range for voltage measurement
(bandwidth 200 Hz)
Lower limit for <1 dB noise error
Average < -25 dBµV
Peak typ. -5 dBµV
CISPR Quasipeak
Standard pulse 25 Hz < - 25 dBµV
Range for voltage measurement
(bandwidth 9 kHz)
Average -7 dBµV
Peak +8 dBµV
CISPR Quasipeak
Standard pulse 100 Hz < -7 dBµV
Level Indication
Digital 3 digit LED display
for reference level
AnalogueMeter with 0 dB centre of instrument.
Voltage linear scale with dB scaling w.o.
logarithmic converter.
Logarithmic scale with -25 dB / 0 dB / +25 dB
(low noise).

Description, Data Sheet FCKL 1528 Page -6
Recording with XY-recorder Y-axis within dynamic
range of demodulator
linear or logarithmic
acc. to meter scale.
X-axis via EPROM list
and D/A-converter
derived from receiver
frequency.
Prefabricated measurement diagrams ready to use.
Error analogue, digital
< 1 dB (0 dB centre of meter, limit)
Demodulation AM, A0 (CW, BFO)
Beat frequencies 0 kHz and 1 kHz.
Both zero beat frequency measurement
and 1 kHz
CW identification is possible even with
200 Hz - I.F.-Filter.
Inputs, outputs
Analogue
Recorder outputs Y-axis, amplitude
0 dB centre of meter
corresponds to 0,5V linear,
logarithmic, Ri < 10 kΩ
X-axis, frequency,
9 kHz at 0 V,
30 MHz at 1,000 V
Pen Down Ri < 2 kΩ
Measuring outputs Active demodulator
(Envelope of I.F.)
0 dB centre of meter
corresponds to
150 mV, Ri > 10 kΩ
Pulse weighted output
see Y-axis xy-recorder
I.F.-output optional
Supply voltages for auxiliaries +12 V / 100 mA
-12 V / 50 mA
Control and supply
L.I.S.N. 4 Bit code
Connector 9-pin socket
Path select, +12 V supply
Conn. 24-pin socket IEEE-Bus-Controller
Options
Tracking generator(optional, build in)
Frequency range 9 kHz-30 MHz
Frequency steps same as receiver
Output voltage 120 dBµV (1 V) / 50 Ω
Control Rotary switch on frontpanel,
Software
Option 19" build in capability
General
Nominal temperature range 0°C to 50°C
Storage temperature range -20°C to +70°C
Cooling Temperature controlled,
low noise cooling fan.
EMI acc. VDE 0876, 1a
Shock, Vibration acc. to DIN IEC 68-2-27/29
Power supply 110,130,220,240 V +-10%
50 , 60 Hz 80 W
12 V DC optional
Cabinet 470 mm x 180 mm x 460 mm
approx. 17 kg
Standard accessories
Mains cable, Operation manual

Description, Data Sheet FCKL 1528 Page -7
Recommended accessories
A) Measuring conducted voltage with
manual or software control.
L.I.S.N. 2 x 10 A NSLK 8127
L.I.S.N. 4 x 16 / 25 ANSLK 8126
L.I.S.N. 4 x 32 / 50 ANSLK 8128
L.I.S.N. 4 x 100 ANNLK 8121
L.I.S.N. 4 x 200 ANNLK 8129
L.I.S.N. 4 x 25 A
150 Ω/ (V) NNBM 8112
L.I.S.N. 2 x 10 A
150 Ω/ (V) NNBM 8114
L.I.S.N. 2 x 10 A
150 Ω/ Delta (symm./asymm.) NNBM 8116
Automotive L.I.S.N.
5 µH // 50 Ω, 70 A, 1 Path NNBM 8125
Automotive
5µH // 50 Ω, 100 A, 1 Path NNBM 8126 A
300 MHz, 10 (20) A NNBM 8126 B
VHF - L.I.S.N.
4 x 25 A, DC/AC 50/60/400 Hz UNN 8122
T - L.I.S.N. (Telecommunication)
T-L.I.S.N
HF, 10 kHz-30 MHz NTFM 8132
T-L.I.S.N.
VHF, 300 MHz NTFM 8133
T-L.I.S.N.
Extremely symmetric NTFM 8135
T-L.I.S.N.
Four wire, 9 kHz-30 MHz
150 ΩNTFM 8138
B) Probes for conducted voltage
R.F.-Probe,150 ΩTK 9415
R.F.-Probe,1,5 kΩTK 9416
R.F.-Probe 2,5 kΩTK 9417
High voltage probe TK 9420
C) Adapters for field strength
Adapter for magnetic
field strength 9 kHz-
30 MHz with constant
conversion factor FMZB 1516
Adapter with small loop,
up to 20 V/m fictive
E-Field-strength FMZB 1517
same as FMZB 1517,
but up to 150 V/m
fictive E-Field-strength FMZB 1527
D) Others
Transformers, converters
Symmetric/Unsymmetric transformer
105 ΩSYM 9223
Current converter
10 kHz-200 MHz SW 9602
Modulator HM 7001 9 kHz-30 MHz for modulated
R.F. acc. to IEC 801
Near field probes FS-SET 7100, magnetic,
elektric, separator, power supply, Box.
FCVU 1534 is the corresponding EMI receiver for
the frequency range 20 MHz 1050 MHz. It is
especially designed for EMI-requirements in this
frequency range. A build in power attenuator
protects the receiver under all circumstances.
The optional external preamplifier uses a standard
coaxial cable for remote power supply and remote
control. Connecting the preamplifier directly at the
antenna eliminates cable loss.
The optional tracking generator delivers 1 V / 50 Ω
. It can be used for filter measurement with
extremely high dynamic range or for testing
attenuation between 2 antennas in free area or
anechoic chamber.
The receivers are similar in manual and PC
controlled operation.
A multitude of antennas, clamps and other
accessories makes this receiver a versatile tool for
EMI - measurement.
This is only a part of our EMI-program. Please ask for
more information.
Equipment may be subject to modification without any
notice. Specifications without tolerance should be
considered as order of magnitude.

SCHWARZBECK MESS - ELEKTRONIK
Manual
Operating Instructions
INTERFERENCE MEASURING RECEIVER
9 kHz - 30 MHz
FCKL 1528
Interference measuring receiver for front panel operation with or without
xy-recorder
and for
PC-controlled operation via IEEE-bus with the SCHWARZBECK
Messbase software.

FCKL 1528 Manual, Operation Instructions
Table of contents
Sections Title Page
1Introduction, Description 1
2Safety-Information, Warning, Mains Voltage Selector/Fuse 2
3Controls (Front panel) 3,4
4Displays and controls, description 5
4.1 Reading of interference voltage 5
4.2 Attenuator area 5
4.2.1 Attenuator display 5
4.2.2 10 dB - steps 5
4.2.3 1 dB - steps 6
4.3 Calibration (key) 6
4.4 Measurement / lin/log Y / Low noise / Low distortion 7
4.5 Frequency - area 7
4.5.1 Frequency display 7
4.5.2 Frequency rotary encoder 8
4.5.3 Frequency steps 8
4.5.4 Manual / automatic tuning 8
4.6 AF / Audio area 9
4.7 Detector area 9
4.7.1 Quasi-Peak Detector QP 9
4.7.2 Peak Detector PK 9
4.7.3 Average Detector AV 10
4.7.4 CISPR-Average CAV 10
4.7.4 CISPR-RMS CRMS 10
5First steps 11
Appendix Pages 12-28
6Front panel operation, automatic scanning 12
7Automatic scanning, recording with xy - recorder 13
8Rear side (description, comments, warnings) 14
9How to connect and adjust the xy - recorder 15
10 Measuring site for interference voltage 16
11 Tracking generator 17, 18
12 Meter (Indication Instrument) and meter reading 19-23
13 Basic Function 24, 25
14 Prefabricated diagrams for the xy - recorder 26, 28

Manual FCKL 1528 Page 1
1. Introduction, Description
The interference measuring receiver FCKL 1528 is a fundamental tool to measure in-
terference voltage, interference field strength, interference current, antenna voltages and
so on with detectors according to quasi-peak, peak and average.
In contrast to spectrum analysers or communication receivers with added "interference
measurement" the FCKL 1528 was especially designed for the requirements of
interference measurement.
It combines the advantages of classic analogue front panel operated receivers such as
Clarity and comprehensibility of the system
Handiness
Reliability
Reading by meter or xy-recording
with the advantages of computer control by efficient and cheap PCs such as
Menu guided software
High dynamic range using AUTORANGE
Introduction of masks
Introduction of antennas
Value added graphics by lin/log-conversion and zoom
Easy documentation.
In both operation modes the special requirements of interference measuring are covered.
Measuring pulses as slow as single click is possible according to the standards.
In addition VARISCAN permits the safe and time saving recording of any spectrum in the
"slow" detector modes CISPR-Quasi-Peak, CISPR-Average and CISPR-RMS by adjusting
the scan speed to signals recognised in advance.
The result is continuous recording without using the peak detector to decide.
A second thought was made to protect the receiver from dangerous overload when used
with a L.I.S.N.. Some powerful devices under test are able to deliver high power to the
receiver. Potential damages are avoided or restricted to relatively cheap components. For
this reason a 10-watt-power attenuator with 10 dB attenuation can be switched into the
signal path directly behind the r. f.-connector.
If used with a remote control Schwarzbeck L.I.S.N. (NSLK 812x rcfm, rcps) the system is
protected by a complete safety net in the receiver, the L.I.S.N. and the software, even if
the components are connected to different mains and are switched on and off at different
times.

Manual FCKL 1528 Page 2
2. SAFETY-INFORMATION, Mains Voltage Selector/Fuse
The receiver is operated with mains voltages from 110 V (100 V) to 240 V. Even if the
receiver is open, no dangerous voltages can be touched because of the fact that the
power supply is a separate box and only low voltages are used outside. Before
opening the power supply disconnect mains!
The power supply is a separate unit together with the rear side cooler. It is connected to the mains via a 3 wire cable with one wire as
safety ground. The standard cable uses a yellow/green colour for safety ground.
This safety ground wire connects the receiver's metal cabinet with the safety ground
of the mains. This means that German VDE standard "Schutzklasse 1" is fulfilled.
In the power supply the safety ground wire is connected to the receiver's ground via a ferrite choke. This was made to avoid rf coupling
because of multi grounding. The wire used for the choke has the necessary gauge for the current needed for the fuses to blow. The
transformer was designed according to the rules of the German standard "Schutzklasse 2" for isolated appliances.
Primary and secondary windings are located on separate parts of the coil former and therefore have a very good isolation and a very
small cross capacitance. Both mains wires are protected by fuses, which can be changed only by using a tool. Mains connector, fuse
holder and voltage switch are one unit. The wire from here go to the transformer via the on/off switch. The wires are double isolated
and secured by an epoxy holder.
The mains switch is also located in the power supply unit and driven by an isolated shaft coming from the front panel. In the receiver
therefor there are no high voltages. The primary part of the power supply is tested for 4000 volts ac eff. 50/60 Hz.
To comply with the regulations of most countries, the receiver was designed for the use with a safety ground connector. If for some
reason a safety ground connection is not wanted, we recommend total isolation by an isolation transformer (100 VA).
If the mains plug of the standard cable has to be changed because of some different
foreign standard, it is very important to connect the yellow/green safety ground to
the safety ground of the mains. This connection has to be checked carefully! In the
final system there is usually a second grounding via the L.I.S.N., which itself is
grounded via the metal wall of the shielding room.
Problems because of this second grounding will not occur because of the ground choke, which is introduced in the safety ground wire of
the receiver.
Extreme care is necessary when connecting a L.I.S.N.: According to CISPR-(16) and
VDE(0876) they use high grounding capazitances. Using a NSLK (50 ΩΩ // 50 µµH +
5ΩΩ) this ground current can reach up to 0,6 A. Such a L.I.S.N. must therefor be
grounded before connecting to mains. Grounding is possible either by connecting
the ground clamps of the L.I.S.N. to the metal wall of the shielding room or by
connecting the rear safety ground clamp with the mains ground. The NSLK-types
use a fixed mains connector which makes a safety ground connection when
plugging in. Double safety is given by the connection to the metal wall of the
shielding room already made before. FI-switches which sense the current on the
safety wire are not useful because of the ground current of the L.I.S.N. This would
result in a instantaneous disconnection. An isolation transformer can be a solution if
such problems occur.
Only qualified personnel is authorised to connect a L.I.S.N.!
Mains Voltage Selector/Fuse Holder
Disconnect mains cable before working on voltage selector/fuse holder!
The receiver uses a linear regulator power supply with a conventional transformer at the
input to avoid any interference problem common with switching regulators. The voltage
selector combined with the fuse holder at the rear panel (Page 14) has to be set to the
local mains voltage. Different mains voltage leads to different supply current, so there are
two different fuse-currents to choose. Remove the holder box with the yellow mains
voltage field by pushing the lever. Insert the correct fuses.
Insert the holder box in the correct orientation for the mains voltage.

Manual FCKL 1528 Page 3
3. FCKL 1524 Controls (Front panel)
The front panel is divided into 8 areas, which unite important controls and displays.
They are as follows:
(1) Meter (4) Meter Reading (7) Detector
(2) Attenuator (5) Receiving frequency (8) R. f.-Input
(3) Calibration (6) A. f.-Audio (9) Mains ON

Manual FCKL 1528 Page 4
(1) METER-area (6)AF-AUDIO-area
Reading of the interference voltage dBµV. Volume control by (6.1).
Upper scale: Log. range of more than 50 dB Rotary switch (6.2) selects audio demodulation.
for an overview (linear dB-scaling). AM demodulation is norm.
Lower scale: linear voltage scaling, BFO position makes unmodulated sine wave signals audible.
dB-scale non linear. Use position 1 k for band A.
Switch off Tracking Generator for Interference Measurement to avoid wrong results!
(2) ATTENUATOR-area (7)DETECTOR-area
7-segment-display 3 digits (2.1) for attenuation Selects detector for the meter,
in dB(µV) under consideration of rf input Left: CISPR Quasi-Peak QP
switch and if attenuation. Rotary Encoder (2.3) Next cw: Peak PK
changes attenuation in 1 dB or 10 dB steps Next cw: Average AV
as selected with rotary switch (2.2) . Next cw: CISPR-Average CAV
Right: CISPR-RMS CRMS
(3) CALIBRATION-area (8)RF-INPUT-area
Push the key for semi automatic calibration of BNC-rf-connector (8.1) (50 ohms unsymmetric input)
the amplification. Click for calibration. Push from L.I.S.N., probe or magnetic antenna.
continuously for check of calibration at the meter. The input switch (8.2) matches the source to the input.
(4) METER READING-area Left: Protected input for L.I.S.N. and probe.
Rotary switch combines both Lin/Log-Y, Lin/Log-X An internal 10 dB-power attenuator protects the
Low Noise / Low Distortion. Left part for Lin X/Y, receiver from dangerous overload.
right part for Log x/y reading. Left centre: Direct input for highest sensitivity.
For continuos signals Log, Low Noise possible. Attention:
Use Lin Low Distortion for slow pulses. Receiver may be damaged by overload!
Do not connect L.I.S.N. or probe in this position!
(5) RECEIVING FREQUENCY-area Right centre: Position for magnetic antenna FMZB 1516/17 with
The display (5.1) shows receiving frequency with 5-digits. measurement in dBµV/m (fictitious el. field-strength)
The significance is different for band A / band B. Right: Position for magnetic antenna FMZB 1516/1517with
The top and bottom segment of the right end digit measurement reading in dBµA/m (magn. field-strength.)
together with the decimal point define - kHz - for
band A and - MHz - for band B. The centre segment is The dBµV-reading (2.1) includes the factors for the protected input,
turned on during the calibration. FMZB 1516/17and if attenuation (3).
The frequency is tuned by the rotary encoder (5.2).
The rotary switch (5.3) chooses the frequency steps (9)Mains switch ON
They are different for band A and B. Frequency input
is locked in the centre position. The receiver can be ordered with built in IEEE-interface. If no bus
Rotary switch (5.4) chooses manual or scan operation. is connected, the interface switch on the back of the receiver must be
Edge positions preset left or right margin in the off position. This is the case if the red "eye" is invisible.
(9kHz, 30MHz) for the xy - recorder.

Manual FCKL 1528 Page 5
4 FCKL 1528 Displays and controls, description
4.1 Reading of the interference voltage in dBµµV
Analogue reading of the inference voltage according to the detectors in dB over 1 µV.
If the attenuator (2.2) and (2.3) is set to 0 dB, the meter reading is directly in dBµV in a
50-ohm-system, assumed that the input switch (8.2) is in the direct input position and
switch (4) is in one of the centre Low distortion positions.
The upper meter reaches from -25 dB to +25 dB with good linear dB-scaling. This
means a logarithmic voltage reading which is related to 0 dB in the centre of the scale.
This logarithmic overview range is active, if switch (4) is in one of its right hand
positions. This overview range permits quasi peak measurements, but there are
limitations when very slow pulses occur and the reading is more than +10 dB on the
meter.
Because of the fact that the logarithmic scale goes down to -25 dB, there is a basic
reading caused by noise for Low distortion (4).
As this noise floor is very low, this is no restriction for practical measurement.
The lower meter gives a linear voltage reading. Because of the logarithmic law
between the dB level and the voltage the density becomes higher and higher on the left
side.
The definition is very high in the range between -5 dB to + 6dB.
This linear voltage range is best choice for high precision measurements based on the
comparison between the signal to measure and the calibration signal.
The input signal is attenuated down to the level (2.2) and (2.3) of the internal calibration
signal.
4.2.1Attenuator display (attenuation in dBµµV)
This 4 digit display (3 digits plus sign) is the result of the attenuation of the step
attenuator (2.3), the high power 10 dB attenuator at the input (8.2) and the 20-dB i. f.-
attenuator, which is active in the extreme left and right positions of the switch (4).
This dB-number plus meter reading is the interference voltage in dB over 1 µV
according to the detector standards.
If the magnetic antenna FMZB 1516 is used and the input switch (8.2) is in the right
position, the reading is dB over 1 µA/m or in the equivalent electric field-strength in dB
over 1 µV/m. In the case of the magnetic field negative dBµA/m-numbers can occur.
4.2.2 10 dB-steps of the input attenuator
With the 10 dB-step attenuator the desired level range of the receiver is controlled. The
dB number visible in (2.1) corresponds to the 0 dB-marker in the centre of the meter
scale and to the 0 dB horizontal centre line of the xy recorder diagram.
The left end of this line touches a small rectangular area, in which this dB number has
to be written.
At the right end of the line the relative level has to be introduced.

Manual FCKL 1528 Page 6
If the input switch (8.2) is in the position "protected input", the range of the 10 dB step
attenuator is from 10 dB to 100 dB (plus 5 dB from the 1 dB-attenuator).
If switch (4) is in the low noise position, the presettable range is from 30 dB to 120 dB
and more if the 1 dB step attenuator and the meter are considered.
If for special purposes a higher sensitivity is needed (down to -10 dBµV), the input
switch (8.2) has to be set to direct input.
In this case the 10 dB high power input attenuator which protects the receiver is not
active.
The lowest number in (2.1) will then be 00 dB, the meter theoretically can be used
down to -10 dB.
The step attenuator of this receiver is binary coded with a maximum attenuation of
95 dB. A control logic with "soft locks" keeps the attenuator well within its limits, even if
the rotary encoder 2.3 is "overturned.
4.2.3 1 dB-steps of the input attenuator
With the 1 dB-step attenuator a measurement based on direct substitution is possible
by comparing an interference voltage to the internal pulse calibration generator (3) and
using the lower meter scale.
In the right position of the rotary switch (2.2) the rotary encoder (2.3) increments or
decrements the attenuator in 1 dB-steps until the same meter reading (for example.
0 dB centre in the lower lin y range) is reached.
Using this method ultimate precision is obtained, which cannot be surpassed by any
other measuring method.
The precision of the attenuator, specified in the data sheet with +-0,5 dB, usually is
better than 0,3 dB.
The "soft locks" mentioned above are also used with 1 dB-steps, but provide 5 dBs
more attenuation (In the 10 dB position of (2.2) the 10 dB-digit is set to 0).
4.3 Calibration key
Initiates semi automatic pulse calibration of the receiver's amplification.
If band A is active by choosing the frequency in the vlf-range 9 kHz-150 kHz, calibration
is done with 200 Hz bandwidth and a pulse frequency of 25 Hz.
In the range 150 kHz-29.999 MHz (band B) bandwidth is 9 kHz and pulse frequency
100 Hz.
Internal calibration is always done with the quasi peak-detector, so it can always be
checked on the meter.
After switching on the receiver, there is always a priority calibration after 1 second.
Always before measurements and repeatedly during warm up a calibration should be
made.
During calibration the meter reading approaches 0 dB centre without reaching it.
For special purposes continuous pressing of the calibration key can be useful.
The most important case is the adjustment of the xy recorder.

Manual FCKL 1528 Page 7
4.4 Meter reading
This rotary switch combines both lin / log y and low noise / low distortion in 4 positions.
The low noise positions reduce internal noise by nearly 20 dB and therefor give a better
reading in the left part of the meter (1), especially in the log y mode.
On the other hand also the test signal is attenuated, which has to be compensated for
by reducing the input attenuator to get the same reading.
This means that the receiver's input gets more voltage which could result in
compression or overload.
Narrow band signals and fast pulses can be measured in this way, but not slow pulses.
The switch positions with log y give an overview range of 50 dB in dB-linear scaling
with the upper scale. This kind of diagram is wide spread, especially with xy-recorders.
Special care has to be taken if slow pulses are present. For this reason prefer the lin y /
Low distortion position of switch 4, because it treats pulses right without any restriction.
If an overview is desired and no slow pulses are present, the position low noise / log y
is ideal.
Choosing lin/log y also determines lin/log x (frequency).
A linear frequency scaling is a disadvantage for band A.
For special purposes you can expand it by higher amplification of the xy recorder.
The above difficulties to match the receiver to an unknown spectrum in order to get a
diagram is completely avoided in a PC controlled system.
The FCKL 1518 together with the Schwarzbeck software "is doing it all by itself".
4.5 Frequency-area
4.5.1Frequency display
This display consists of 6 pieces 7-segment-digits.
Five of them give the frequency number and one of them (right corner) shows the
status.
This gives easy and precise frequency reading especially for interference measurement
purposes.
Only the relevant digits are displayed.
In band B the most significant digit is 10 MHz, the lowest significant is 1 kHz.
In band A the most significant digit is 100 kHz, the lowest significant is 10 Hz.
Tuning downward from band B below the basic limit of 150 kHz (00.150), nothing
changes until 100 kHz (00.100) is reached.
This info range is not related to any standard and also the amplification of the receiver
decreases rapidly because of input filtering.
Do not calibrate (3) in this range, because this leads to errors on other frequencies!

Manual FCKL 1528 Page 8
29.999 MHz
CALIBRATION
kHz
Band A
9k-149,99k
Band B
0,15M-29,999M
(Info to 0,1M)
00.150 MHz
CALIBRATION
kHz
Band A
9k-149,99k
Band B
0,15M-29,999M
(Info to 0,1M)
00.100 MHz
CALIBRATION
kHz
Band A
9k-149,99k
Band B
0,15M-29,999M
(Info to 0,1M)
150.00 MHz
CALIBRATION
kHz
Band A
9k-149,99k
Band B
0,15M-29,999M
(Info to 0,1M)
009.00 MHz
CALIBRATION
kHz
Band A
9k-149,99k
Band B
0,15M-29,999M
(Info to 0,1M)
MHz kHz
kHz Hz
29.999 MHz
CALIBRATION
kHz
Band A
9k-149,99k
Band B
0,15M-29,999M
(Info to 0,1M)
00.150 MHz
CALIBRATION
kHz
Band A
9k-149,99k
Band B
0,15M-29,999M
(Info to 0,1M)
150.00 MHz
CALIBRATION
kHz
Band A
9k-149,99k
Band B
0,15M-29,999M
(Info to 0,1M)
009.00 MHz
CALIBRATION
kHz
Band A
9k-149,99k
Band B
0,15M-29,999M
(Info to 0,1M)
MHz kHz
kHz Hz
Tuning direction band B to A Tuning direction band A to B
Switching frequency Switching frequency
Info - Bereich
4.5.2Frequency encoder
The manual frequency tuning is made by rotating the frequency encoder. Turning cw
increases, ccw decreases frequency. The frequency steps are chosen by the rotary
switch (5.3).
4.5.3Frequency steps
This rotary switch determines, if the frequency decoder (5.2) controls the first or second
digit of the display or if the input is locked. The significance of the digits depends on the
frequency range the receiver is in. By that strategy, the tuning behaviour is
automatically optimised for the different bandwidths in the 2 bands. Already in manual
mode this is a nice feature, but it's ideal when working with an xy recorder, because the
complete range can be scanned without any switching.
FREQUENCY STEPS
Coarse FineLock
5.3
Coarse: 100 Hz - steps in band A 10 kHz - steps in band B
Fine:10 Hz - steps in band A 1 kHz - steps in band B
The position of this switch determines both manual tuning and automatic
scanning (think of lock position if nothing happens!)
To detect narrow band signals steps have to be chosen "Fine". This is especially true if
xy-recorder is used. For an overview or frequency hopping "Coarse" is faster.

Manual FCKL 1528 Page 9
4.5.4Rotary switch
to select manual or automatic tuning and xy-recorder positioning. In the Man position
the receiver's frequency is tuned by the encoder. In the Start position a clock generator
does this tuning work. The scanning procedure always begins at 9 kHz or at the
frequecy tuned with Man and is only possible for rising frequency. The 2 edge positions
set the frequency to 9 kHz or 29.999 MHz respectively. This makes life easier when
adjusting the xy recorder to a diagram.
4.6 AF/AUDIO
This area contains both a. f.-volume control (6.1) and demodulator switch (6.2). The
a. f.-volume control works just like in a radio receiver, but it has to be considered, that
especially in band A the loudness sometimes is poor. The reason is that the very
narrow bandwidth of 200 Hz can only deliver very low a.f. frequencies to the
loudspeaker which is too small for this purpose. Often the operator compensates for
this low volume by increasing a.f. amplification with the volume control. This results in
overloading and by that harmonic distortion is produced. This harmonic distortion then
gives higher volume. In the norm position of the demodulation switch input signals are
demodulated as if they were amplitude modulated, which is the case for most of the
signals in this frequency range, especially broadcast stations. Pulse noise and
calibration signal can be monitored well in this position. The positions BFO 0k and BFO
1k are useful if unmodulated narrow band signals occur. Being unmodulated, there is
no information to listen to. Only some variation in basic noise can be monitored. If a
BFO is in use, the differential frequency between input signal and receiving frequency
occurs. This differential frequency is exactly the difference between these two
frequencies if the switch is in the 0 k position. If the difference is 0 (zero beat) both
frequencies are equal. For the narrow bandwidth of band A an audible difference
frequency cannot appear. The problem is solved by using BFO 1k position. Both
frequencies are equal if a 1 kHz difference frequency is heard. Due to the more and
more automatic measurements these considerations seem to be less important. But it
is still very important especially when working without shielding room to verify a signal
to know if it is interference or broadcast. Also the acoustic signature of a signal gives
some information.
4.7 Selecting detectors, QP, PK, AV, CAV, CRMS
Select detectors according to the standard.
Continuous sine wave signals give the same reading on all detectors.
Changing signals and pulses give different readings.
4.7.1CISPR Quasi-Peak QP
This detector has a pulse weighing characteristic which considers the annoyance.
If single clicks or slow pulses are to be measured, choose lin y / low distortion of
switch 4. Highest precision is obtained, if both attenuators (2.2) and (2.3) are used to
adjust the signal to the 0 dB marker of the linear (lower) scale. The precision is then
better than required. The measurement reading can be done in the display (2.1) for 0
dB (centre) meter reading.
4.7.2Peak PK
Centre position of switch (7) gives reading of the unvalued peak voltage.
The Peak Detector has an extremely short charge time constant and is self-resetting.
The measurement is the peak value, related to the bandwidth, based on the calibration
of the effective value of a sine wave.

Manual FCKL 1528 Page 10
4.7.3Average AV
In this position the average of the demodulated i. f. signal is measured.
A time constant is used to give a constant reading for pulses with repetition frequencies
>100 Hz. This Average Detector behaves like the classic Average detector which has
been familiar to the EMC - communty for the last 50 years.
4.7.4 CISPR-Average CAV
Just like the classic AV, but with a critcally damped second order low pass filter with a
time constant of 160 msec. The pulse weighing for fast pulses is the same, but the
behaviour for slowly changing (narrow band) signals is completely different.
4.7.5 CISPR-RMS CRMS
This detector has a weighing function which considers the effects of disturbance to
digitally modulated signals.
Basically it uses a RMS - Detector with a specified corner frequency followed by
critcally damped second order low pass filter with a time constant of 160 msec.

Manual FCKL 1528 Page 11
5. First steps
5.1 Front panel operation, manual tuning
Attention: Read safety informations page 2 very carefully. Before connecting receiver to mains,
select mains voltage and fuse-current on the rear pannel voltage selector/fuse holder.
Attention: The receiver can have a built in IEEE - interface. Front panel operation is only possible if
the rear switch is in the off-position. This switch is off if the "red eye" is invisible.
A) Set all switches to the position marked by the hand-symbol in the picture on this page.
Switch 2.2 in the left position, turn 2.3 until 60 dBµV is reached as attenuator reading.
Set the A.F.- volume in half position.
B) Switch on the receiver by pushing (9).
C) About 1 second after switching on a pulse is heard. The meter reading approaches
centre (0 dB) and then returns to the left end of the scale. This was the automatic
priority calibration with 100 Hz pulses according to band B 150 kHz.
The receiver is now ready to use and frequency is tuned by rotating the encoder (5.2).
The steps can be selected with (5.3) fine or coarse.
Fine permits narrow band signals to be tuned easily. Coarse is ideal for broad pulse
spectrums, and frequency hopping.
For overviews it is ideal to choose Log. indication with Low Noise (4) and reading the
upper meter scale (1).
If the frequency is tuned with the encoder (5.1) from 00.150 MHz (150 kHz band B) in
direction to lower frequencies, the receiver switches to band A at 00.100 MHz (100 kHz),
to give to the user an information below the frequency limit (info).
Then follows the change to band A and the frequency display changes to 150.00kHz.
The right lowest significant digit is then 10 Hz! If the frequency is increased, the frequency
changes to 00.150 MHz / band B.
In the right corner of the frequency display (5.3) the upper or lower segment shows band
A or B.
After this change between band A/B a recalibration is good practice (3).