Wulfsberg Electronics Division VC 401B Installation Guide
Chelton Avionics Inc.
A Chelton Group Company
6400 Wilkinson Drive
Prescott, AZ 86305
U.S.A.
Series III Avionics
Pilot's Guide
Publication No. 150-040564 Rev. A January 2000
Series III Avionics
Pilot's Guide
Wulfsberg Electronics Division, located in Prescott, Arizona, designs and manufactures the Chelton
Series III line of products, including the VCS-40A VHF Communications System. For more than 25 years,
Wulfsberg Electronics has distinguished itself by providing top quality avionics products for civil, air
transport, and military applications.
Information in this manual is subject to change without notice. No part of this manual may be reproduced
or transmitted in any form or by any means, electronic or mechanical, without express written permission
of Chelton Avionics, Inc.
Chelton Avionics, Inc. makes no warranty, expressed or implied, with regard to this manual, including but
not limited to any implied warranties of merchantability, fitness for a particular purpose, and noninfringement. In addition, Chelton Avionics, Inc. makes no warranty with regard to the documentation or
data contained herein. Chelton Avionics, Inc. is not liable in the event of incidental, special,
consequential, or any other damages in connection with or arising from furnishing, performance, or use of
this manual.
2000 Chelton Avionics, Inc. All rights reserved
VCS-40A, VC-401B, CD-402B, VNS-41A, VN-411B, CD-412B, CD-413B, TRS-42A, TR-421B, CD-422B,
DFS-43A, DF-431B, CD-432B, DMS-44A, DM-441B, and SD-442B are trademarks of Chelton Avionics, Inc.
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Series III Avionics
VCS-40A VHF Communications System...................................................................................................................1
General Description................................................................................................................................................1
CD-402B Control Display Unit..............................................................................................................................2
CD-402B Controls (Fixed Channel Spacing) .........................................................................................................3
CD-402B Controls (Switchable Channel Spacing).................................................................................................3
CD-402B Controls (All).........................................................................................................................................4
CD-402B Display...................................................................................................................................................5
Operating the VCS-40A .........................................................................................................................................6
VCS-40A Notes......................................................................................................................................................8
VCS-40A System Block Diagram (Typical) ..........................................................................................................9
VNS-41A VHF Navigation System...........................................................................................................................10
General Description..............................................................................................................................................10
CD-412B Control Display Unit............................................................................................................................11
VNS-41A Controls...............................................................................................................................................12
VNS-41A Display.................................................................................................................................................13
Operating the VNS-41A.......................................................................................................................................15
VNS-41A Notes....................................................................................................................................................16
VNS-41A System Block Diagram (Typical)........................................................................................................17
Pilot's Guide
TRS-42A ATC Transponder System........................................................................................................................18
General Description..............................................................................................................................................18
CD-422B Control Display Unit............................................................................................................................19
TRS-42A Controls................................................................................................................................................20
CD-422B Display.................................................................................................................................................23
Operating the TRS-42A........................................................................................................................................25
TRS-42A Notes ....................................................................................................................................................26
TRS-42A System Block Diagram (Typical).........................................................................................................27
DFS-43A Automatic Direction Finder System........................................................................................................28
General Description..............................................................................................................................................28
CD-432B Control Display Unit............................................................................................................................29
DFS-43A Controls................................................................................................................................................30
Operating the DFS-43A........................................................................................................................................34
DFS-43A Notes ....................................................................................................................................................35
DFS-43A System Block Diagram (Typical).........................................................................................................36
DMS-44A Distance Measuring System....................................................................................................................37
General Description..............................................................................................................................................37
SD-442B Selector Display Unit............................................................................................................................38
DMS-44A Controls...............................................................................................................................................39
Operating the DMS-44A.......................................................................................................................................41
DMS-44A Notes...................................................................................................................................................42
DMS-44A System Block Diagram (Typical) .......................................................................................................43
Page iii
Series III Avionics
Pilot's Guide
VCS-40A VHF Communication System
General Description
The Chelton VCS-40A VHF Communications System is a fully synthesized ATC VHF transceiver. The
VCS-40A system consists of a lightweight, remote-mounted VC-401B transceiver and a panel-mounted
CD-402B Control Display Unit.
The VC-401B transceiver is available with fixed 25 kHz channel spacing, fixed 8.33 kHz channel spacing
for European airspace, and switchable 25 kHz - 8.33 kHz channel spacing. Operation over the frequency
range of 118.00 – 136.975 MHz is standard. Extended operation over the frequency range of 118.00 –
151.975 MHz is available as an option .
The VC-401B features a coherent squelch system that permits the receiver to respond only to on-channel
signals, rejecting high-level noise. This makes it ideal for CLIMAX operations. The system also features
built-in SELCAL and ACARS capabilities for regional airlines and major fleet operators.
Reliability of the VC-401B is substantially increased by a specially designed thermal protective device that
enables continuous operation at reduced power (instead of the full 20 watts rated output) without
damaging the transceiver. A heavy-duty heat sink accommodates continuous operation, and a unique
cooling fin design dissipates heat, decreases internal unit temperatures and increases service life.
The CD-402B Control Display Unit is available in versions for use with transceivers with fixed channel
spacing (25 kHz or 8.33 kHz), and for units with switchable (25 kHz and 8.33 kHz) channel spacing.
The CD-402B Control Display Unit provides a simultaneous readout of two frequencies: The active
frequency in the upper display and, immediately below it, the standby frequency. Frequency switching is
accomplished by simply pressing a frequency transfer button. The Transmit Annunciator (Tx) appears in
the display when RF is present at the output of the transceiver, providing positive proof-of-operation.
When the VC-401B System is turned on, a diagnosis of all critical circuits begins, and continues until the
System is turned off. If a fault is detected at any time, a FAIL annunciation appears in the display.
The VCS-40A System has a nonvolatile memory which allows it to remember the last frequencies
displayed, indefinitely, even when power is removed. This feature prevents momentary power interrupts
from affecting the system, and allows the last frequencies used to appear immediately when the System
is turned on.
The VCS-40A System provides ARINC format 429 output for external use, and can also be tuned by
ARINC format 429 commands from external equipment such as an RMS-555 Radio Management
System.
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Series III Avionics
CD-402B Control Display Unit
Pilot's Guide
Page 2
Series III Avionics
CD-402B Controls (Switchable Channel Spacing)
Pilot's Guide
Off/On Channel Spacing Selector and TEST
Pushbutton
OFF
the last frequencies displayed in the system's
non-volatile memory.
25
- Activates the VCS-40A System. Selects 25 kHz
channel spacing. The last frequencies displayed
reappear on the display.
8.33
frequencies displayed reappear on the display.
TEST Pushbutton
- Deactivates the VCS-40A System. Records
- Selects 8.33 kHz channel spacing. The last
Disables the squelch circuits to allow audible
verification of receiver operation.
CD-402B Controls (Fixed Channel Spacing)
Off/On/Test Function Selector
OFF
the last frequencies displayed in the system's
non-volatile memory.
ON
frequencies displayed reappear on the display.
- Deactivates the VCS-40A System. Records
- Activates the VCS-40A System. The last
TST
- Disables the squelch circuits to allow audible
verification of receiver operation.
Page 3
Series III Avionics
CD-402B Controls (All)
Pilot's Guide
Frequency Knobs
The outer knob tunes the transmit/receive frequency
in whole MHz steps (118, 119, 120, etc.). The inner
knob tunes in 25 or 8.33 kHz steps (refer to the table
on page 6).
Volume Control (Optional)
the receiver audio volume.
Frequency Transfer Button
Press and release to exchange active and standby
frequencies. Press and hold 2 seconds to remove
the standby frequency so that the active frequency
can be changed. Press and hold 2 seconds again to
restore the standby frequency.
- Inner knob controls
Press and hold for 7 seconds or longer to set the
active frequency to 121.50 MHz.
Page 4
Series III Avionics
CD-402B Display
Pilot's Guide
Active Frequency
The upper line of the display always shows the active
frequency
Active Annunciator
…which is indicated by the Active Annunciator (the letters
ACT).
Standby Frequency
The lower line of the display shows the standby frequency.
When both frequencies are shown, rotating the
FREQUENCY KNOBS changes the standby frequency.
…
Transmit Annunciator
The Transmit Annunciator (the letters Tx) indicates an RF
output of the transmitter. It appears when the microphone
is keyed.
System Number
The System Number indicates that this display is for COM
System 2 (when more than one system is installed). The
number 1 indicates that this display is for COM System 1
(when more than one system is installed).
If only one COM System is installed or if this Control
Display Unit controls COM 3 in a three-radio system, the
display shows a blank instead of 1 or 2.
FAIL 1
failure. Neither transmitter nor receiver is operative.
FAIL 2
Transmitter only failure. This is displayed only when the
microphone is keyed. The receiver is still operative unless
FAIL 1
in the lower line of the display indicates a System
in the lower line of the display indicates a
is displayed with the mic rophone not k e yed.
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Series III Avionics
Operating the VCS-40A
1. Turn the SELECTOR to ON (fixed channel spacing) or to 25 or 8.33 (switchable channel spacing).
The last frequencies selected prior to System turnoff reappear in the display.
2. If these are not the desired frequencies, rotate the appropriate FREQUENCY KNOB until the desired
frequency is displayed as the standby frequency in the lower line of the display.
The large frequency knob increments (clockwise rotation) or decrements (counter-clockwise rotation)
the frequency being tuned by one megahertz for each detent.
The small frequency knob increments (clockwise rotation) or decrements (counter-clockwise rotation)
the frequency being tuned by 25 kHz or 8.33 kHz for each detent.
For 8.33 kHz channel spacing, the small frequency knob sequences through a list of both 25 kHz and
8.33 kHz channels (see table below).
Frequency (MHz) Channel Spacing (kHz) Channel Name
Pilot's Guide
118.0000 25 118.000
118.0000 8.33 118.005
118.0083 8.33 118.010
118.0167 8.33 118.015
118.0250 25 118.025
118.0250 8.33 118.030
118.0333 8.33 118.035
118.0417 8.33 118.040
118.0500 25 118.050
118.0500 8.33 118.055
118.0583 8.33 118.060
118.0667 8.33 118.065
118.0750 25 118.075
118.0750 8.33 118.080
118.0833 8.33 118.085
118.0917 8.33 118.090
118.1000 25 118.100
.
.
.
136.9750 25 136.975
136.9750 8.33 136.980
136.9833 8.33 136.985
136.9917 8.33 136.990
.
.
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Series III Avionics
3. Press and release the FREQUENCY TRANSFER button. This exchanges the two displayed
frequencies. The desired frequency is now active and may be used immediately.
4. Use the VOLUME CONTROL to adjust volume if a station is broadcasting.
5. To set a new standby frequency, rotate the appropriate FREQUENCY KNOB until the desired
frequency is displayed in the lower line of the display.
Pilot's Guide
NOTE:
To tune the active frequency only (without first tuning the standby and then "flipping" the
frequencies), press and hold the FREQUENCY TRANSFER button for two seconds, then
release it. This removes the standby frequency from the display.
The FREQUENCY KNOBS may now be used to change the active frequency.
Press and hold the FREQUENCY TRANSFER button for two seconds again to restore the
standby frequency to the display, if desired.
Page 7
Series III Avionics
VCS-40A Notes
1. The FREQUENCY SELECTOR knobs tune the VC-401B transceiver directly. The display shows the
frequencies to which the VC-401B transceiver is actually tuned. The transceiver may also be tuned
by an ARINC 429 digital bus.
2. Display intensity and panel lighting are controlled by external dimmer controls.
3. Pressing and holding the FREQUENCY TRANSFER button for at least 7 seconds before releasing it
sets the COM frequency to 121.50 MHz. This is true even if segments of the display are faulty or a
lighting failure occurs. From this known reference point, any other frequency may be set by counting
detents of the FREQUENCY SELECTOR knobs as they are rotated. Each clockwise detent of the
outer knob is one Megahertz difference. Each clockwise detent of the inner knob is 25 or 8.33 kHz
difference.
4. The FREQUENCY SELECTOR knobs rotate continuously through all detents without end stops.
After rotating the outer knob clockwise to the highest number, the next detent will be the lowest
number (118 MHz).
Pilot's Guide
Page 8
Series III Avionics
VCS-40A System Block Diagram (Typical)
Pilot's Guide
Page 9
Series III Avionics
Pilot's Guide
VNS-41A VHF Navigation System
General Description
The Chelton VNS-41A VHF Navigation System is a lightweight 200-channel microprocessor-based VHF
navigation receiving system that combines VOR/LOC, glideslope, and marker beacon reception in the
same unit. The VNS-41A is compatible with most HSIs, CDIs, and conventional marker beacon displays.
The ARINC 429 serial data bus interface is compatible with EFIS displays, radio management systems
(RMU), and flight management systems (FMS).
The VNS-41A system consists of a remote mounted VN-411B VHF Navigation Receiver and a panel
mounted CD-412B or CD-413B Control Display Unit.
In addition to processing signals for external use (Marker Beacon Lamps and audio, AFCS, CDI, HSI,
EFIS, etc.), the VNS-41A can digitally display BEARING TO or RADIAL FROM any selected VOR station
on the CD-412B/CD-413B with the function selector panel control.
When an ILS frequency is selected by the VNS-41A, the letters LOC appear below the frequency on the
display when RAD or BRG are selected.
Digital circuit design of the VNS-41A incorporates microprocessor technology to achieve performance,
reliability, accuracy, and features not possible in previous systems. These include advanced filtering
techniques, full-time self-diagnostics, non-volatile frequency memory and continuous calibration.
Special filtering circuits virtually eliminate noise, including rotor modulation noise in helicopter
installations. Self-testing begins when the system is turned on, and continues until turnoff. Faults
detected result in a FAIL annunciation.
Non-volatile memory means that the last frequency selected is in system memory if the system is turned
off, if power is interrupted, or even if the system is removed from the aircraft!
The VNS-41A is TSO'd. It is fully compatible with other equipment using ARINC Characteristic 429
Digital Information Transfer. Frequencies may be controlled remotely by a Navigation Management
System (NMS) and interfaced with an Area Navigation (RNAV) System.
Page 10
Series III Avionics
CD-412B Control-Display
Pilot's Guide
Page 11
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