Valcom AS-1735/SRC User manual

Valcom Manufacturing Group, Inc
175 Southgate Drive, P.O. Box 603, Guelph, Ontario, Canada N1H 6L3 Tel: [phone] Fax: [phone]
Web Site: www.valcommfg.ca E-mail: [email protected]
TECHNICAL MANUAL
VTM-01-003 Rev C
OPERATION AND INSTALLATION
INSTRUCTIONS
AS-1735/SRC ANTENNA

AS-1735/SRC VTM-01-003C
Valcom Mfg Grp, Inc.
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REVISION SHEET
Revision Description Date
A Original Issue July 20, 2001
B Various formatting changes to improve readability May 28, 2002
C Updated contact information October 7, 2013
Errors in this publication can be reported to the Manufacturer.
Refer to Section 6 for contact information.

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TABLE OF CONTENTS
Section Page
1.0 GENERAL INFORMATION .............................................. 1
1.1 Scope .......................................................... 1
1.2 Description ..................................................... 1
2.0 INSTALLATION ........................................................ 3
2.1 Unpacking ...................................................... 3
2.2 Handling ....................................................... 4
2.3 PowerRequirements .............................................. 4
2.4 Cabling ........................................................ 4
2.5 Site Preparations ................................................. 4
2.6 InstallationRequirements ...........................................4
2.7 Alternate Installation Method ....................................... 8
3.0 OPERATION .......................................................... 10
3.1 FunctionalDescription ........................................... 10
3.2 OperatingProcedures ............................................ 10
4.0 TROUBLE SHOOTING AND MAINTENANCE ............................. 11
4.1 General ........................................................11
4.2 EquipmentRequired ............................................. 11
4.3 Typical Troubles ................................................ 11
4.4 PreventativeMaintenance ......................................... 11
5.0 PARTS LIST .......................................................... 12
5.1 General ....................................................... 12
6.0 QUICK REFERENCE DATA ............................................ 13
6.1 General ....................................................... 13
6.2 Manufacturer'sAddress .......................................... 13

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LIST OF TABLES AND FIGURES
TABLES
Table 1.1 - Electrical Properties of the AS-1735/SRC Antenna ......................... 1
Table 1.2 - Mechanical Properties of the AS-1735/SRC Antenna ....................... 2
Table 5.1 - Parts supplied with AS-1735/SRC antenna Shipment ...................... 12
Table 5.2 - Optional Parts available for the AS-1735/SRC antenna .................... 12
FIGURES
Figure 2.1 - Identifying the main sections of the AS-1735/SRC ........................ 3
Figure 2.2 - Mounting the AS-1735/SRC around masts of 4 inches to 12 inches ........... 5
Figure 2.3.a - Lower mounting hole dimensions of the AS-1735/SRC antenna ............ 6
Figure 2.3.b - Upper mounting hole dimensions of the AS-1735/SRC antenna ............ 7

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1.0 GENERAL INFORMATION
1.1 Scope
This manual is intended for the purpose of installing, operating and maintaining the AS-
1735/SRC antenna.
1.2 Description
The AS-1735/SRC antenna is a UHF (ultra high frequency) antenna which provides vertically
polarized transmissions and receptions in an omnidirectional radiation pattern across the 225 to
400 MHz frequency range. Optimal operation is achieved when the antenna is mounted on
masts of 12 inches in diameter down to 4 inches in diameter. As an option, the antenna can also
be mounted on masts of 12 inch to 15 inch diameters through the use of Extended Feed Line
Sections in the Lower Feed Assembly. The part number for these Extended Feed Line Sections
is VD-00-00225-2 and they are available on request from the manufacturer (See Section 6 for
contact information).
The AS-1735/SRC antenna is comprised of a four-element array with each element equally
spaced around a central mountable mast. The broadband elements are fed in-phase with each
other and work together to obtain an omnidirectional radiation pattern in the Azimuth plane. The
elements are fed by an integral coaxial line matching transformer and transmission line network
all coupled from a single coaxial input to the antenna. Installation of the antenna is simplified
through the use of flange mounts and standard hardware.
Table 1.1 - Electrical Properties of the AS-1735/SRC Antenna
Operating Frequency Range 225 MHz to 400 MHz
Input Impedance 50 Ohms Nominal
Voltage Standing Wave Ratio (VSWR) 1.8:1 maximum
Gain +2 dB above an isotropic source
Power Rating 2 kW PEP (Peak Envelope Power)
Input Connector UG-352/U
Polarization Vertical
Radiation Pattern Omnidirectional within ±2 dB in the azimuth
plane when mounted on 11" diameters or less

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Table 1.2 - Mechanical Properties of the AS-1735/SRC Antenna
Weight 31 lbs (14 kg)
Finish Epoxy polyamide paint, colour Haze Grey
Mounting Position Vertical mast of 4 to 12 inch (10.2 to 30.5 cm) dia.
*Optional 12 to 15 inch (30.5 to 38.1 cm) dia.
Overall Dimensions 29-3/4 in (wide) x 29-3/4 in (deep) x 28-1/4 in (high)
(75.6 cm (wide) x 75.6 cm (deep) x 71.8 cm (high))
Temperature Storage : -140°F to +158°F (-95°C to +70°C)
Operating : -76°F to +140°F (-50°C to +65°C)
Wind Loading Operating : 75 mph (120 km/h)
Survival : 120 mph (192 km/h)
Shock per MIL-S-910C, Grade A, Class I, Type A
Vibration per MIL-STD-167, Type I
* See Section 6 for contact information

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Figure 2.1 - Identifying the main sections of the AS-1735/SRC
2.0 INSTALLATION
2.1 Unpacking
The AS-1735/SRC antenna is shipped along with two Technical Manuals within the same
shipping container. Carefully pry off the lid of the shipping container to find the antenna and the
two manuals in amongst the packing material. See Figure 2.1. Lift out the top layer of packing
material and carefully remove the antenna. Remove any additional packing material and note
that the antenna has not suffered any damage from shipping.
Note :
The shipping container is reusable.
Save it for repackaging the antenna for further shipments.
2.2 Handling

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Care must be taken with the antenna so as not to damage any of the flanges or contacts nor to
chip or scratch the painted surfaces of the antenna. No special handling procedures are
necessary.
2.3 Power Requirements
The As-1735/SRC antenna has an RF power handling capability of 2 kW Peak Envelope Power
in the 225 MHz to 400 MHz range. This is inputted through an LC type, UG-352/U RF
connector which is located at the centre of the Lower Feed Section. No other power sources are
required.
2.4 Cabling
The AS-1735/SRC antenna is designed to mate with the UG-154A/U connector of the
transmission line via a UG-352/U connector. The transmission line should be tied down to the
mast to prevent excessive stress on the connector assemblies of both the transmission line itself
and the antenna.
2.5 Site Preparations
The AS-1735/SRC antenna has been designed for shipboard use and is intended to be installed
around a self-supporting mast of diameters between 4 and 12 inches (up to 15 inch masts can be
supported by special order). The Antenna can also be used in shore applications so long as the
installation requirements laid out in this manual are maintained.
2.6 Installation Requirements
Note :
The optimum installation layout for the AS-1735/SRC antenna is determined on a
ship-by-ship basis. The particular installation plans for the ship should be consulted.
The AS-1735/SRC antenna is designed to be installed around a 12 inch vertical mast. Four
radiating elements encompass the mast, each 90 degrees from each other and joined by a
common feed point. Refer to Figure 2.2 for a visual illustration.

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Figure 2.2 - Mounting the AS-1735/SRC around masts of 4 inches and 12 inches
The antenna is shipped fully assembled and can be thought of having three main sections to it;
the Lower Feed Section and the Left-hand and Right-hand Radiating Element Sections (see
Figure 2.1). The Lower Section is equipped with three mounting flanges. Each flange has 2 bolt
holes to accommodate 3/8" hardware. The Radiating Elements are equipped with two mounting
flanges each spaced 90° apart. These mounting flanges have 4 bolt holes which also
accommodate 3/8" hardware. For dimensions of bolt holes, see Figures 2.3.a and 2.3.b.

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Figure 2.3.a - Lower mounting hole dimensions
of the AS-1735/SRC antenna

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Figure 2.3.b - Upper mounting hole dimensions of the AS-
1735/SRC antenna

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Support assemblies must be provided between the mast and the antenna’s Radiating Element
Sections and Lower Feed Section for proper installation of the antenna. The support assemblies
are not supplied by the manufacturer.
Various types of support assemblies may be utilized in the installation of the AS-1735/SRC
antenna. The type of assembly used depends upon the mast size. However, it is imperative that
proper alignment, positioning and location of the mounting holes of the support assembly be
maintained. If misalignment exists, the AS-1735/SRC will suffer excessive stress levels which
will greatly reduce the reliable lifespan of the antenna.
The antenna must be mounted on the mast so that it is high enough to clear any obstructions
which may hinder the antenna’s “line of sight” mode of operation. A minimum vertical spacing
of 4 feet must be maintained between the AS-1735/SRC and any other projections from the mast.
This is to ensure full efficiency of the antenna and also to protect against damage to other
equipment by the high power levels radiating from the antenna.
Orientation of the elements of the AS-1735/SRC is not critical as the antenna is designed to
provide omnidirectional radiation in the azimuth plane.
The easiest recommended installation is to raise the antenna to the top of the mast then sliding it
down over the mast and bolting it to the appropriate mounting location. If possible, the mast
may even be lowered to a near horizontal state and the antenna slipped over the top of the mast.
Line up the bolt holes of the seven flanges to the support assembly attached to the mast. Use
stainless steel hardware, such as 3/8" bolts and lock washers (not supplied), to fasten the antenna
to the support assembly. Note :
The use of an anti-seize thread compound per MIL-A-907
is highly recommended on the threads of all hardware.
Use some touch-up paint to seal around the joint where the seven antenna mounting flanges meet
the support assembly. Also touch up any chips which may have occurred on the hardware during
disassembly.
2.7 Alternate Installation Method
In some instances, it may not be possible to raise the antenna over top of the mast, nor to lower
the mast to a comfortable working height. If this is the case, it may be necessary to separate the
AS-1735/SRC into the three main sections, as identified in Figure 2.1, by removing both sets of
the four screws at the top of the two elbow joint flanges. Keep the hardware and the two rubber
O-rings in a safe place for re-assembling.

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Note :
When disassembling, be cautious not to bend or break the inner conductors and do not let any
moisture to enter the inside of the antenna.
The AS-1735/SRC can now be installed by bolting one of the Radiating Element Sections to the
support assembly attached to the mast by stainless steel hardware, such as 3/8" bolts and lock
washers (not supplied), but do not tighten the bolts all the way yet. Bolt the second Radiating
Element Section to the mast in a similar fashion, again, do not tighten the bolts yet. Place the
previously removed O-rings in each of the grooves of the Lower Feed Section and, lining up the
inner conductor bullet connections, attach the Lower Feed Section to the two Radiating Element
Sections. Use the stainless steel hardware previously removed to secure the three sections
together. Tighten the screws to 8.5 ft-lbs (+/-0.5 ft-lbs). Bolt the Lower Feed Section to the
support assembly attached to the mast by stainless steel hardware; such as 3/8" bolts and lock
washers (not supplied). All mounting bolts can now be fully tightened as specified on the
support assembly’s documentation.
Note :
The use of an anti-seize thread compound per ML-A-907 is
highly recommended on the threads of all hardware.
Use some touch-up paint to seal around the joint where the elbow flanges have just been joined,
as well as where the seven antenna mounting flanges meet the support assembly. Also touch up
any chips which may have occurred on the hardware during disassembly.

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3.0 OPERATION
3.1 Functional Description
The AS-1735/SRC antenna consists of four dipole radiators fed in phase and positioned equally
spaced around a circular mast. This configuration provides an omnidirectional radiation pattern
in the azimuth plane over the frequency range of 225 MHz to 400 MHz which is capable of
power inputs up to 2 kW peak.
The dipole elements are supported by an aluminum frame which also forms the outer conductors
of the coaxial feed lines and transformers. Each dipole is fed through a balun and utilizes
isolation traps to limit the flow of current in the mast.
The impedance of the radiating elements is essentially high. Impedance matching is achieved by
pairing two elements in parallel and then parallelling those with the other two elements, which
are also in parallel to each other.
The radiation pattern of the antenna is essentially that of a vertically polarized dipole. When the
antenna is mounted on masts of 11 inches in diameter or smaller, the radiation pattern is
omnidirectional to within ±1.5 dB. When the antenna is mounted on larger diameter masts, the
pattern tends to show slight nulls but is still relatively omnidirectional.
The design of the antenna has been driven to provide a lightweight, rugged, reliable and
weatherproof antenna. This has been achieved through minimal assembly parts and in such a
way that installation can be done in a variety of ways without noticeable differences in operation
performance.
3.2 Operating Procedures
The AS-1735/SRC exhibits complete broadband operation over the frequency range of 225 MHz
to 400 MHz in which the antenna requires no special procedures to operate. The antenna is
ready to use upon completion of installation.

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4.0 TROUBLE SHOOTING AND MAINTENANCE
4.1 General
Problems in transmission and reception applications can be the result of faulty equipment,
transmission lines or the antenna. If problems occur in the operation of the system, check first
and ensure the problem is not being caused by another piece of equipment or the transmission
line. The AS-1735/SRC can be checked as described in this section.
4.2 Equipment Required
Due to the design of the AS-1735/SRC, trouble shooting tactics are limited to visual inspections
of the various components. The antenna’s internal electrical system contains a DC short to
ground so any continuity tests will always indicate a short circuit. This is normal. Other than a
screwdriver, no special tools are required.
4.3 Typical Troubles
The main area of concern would be the UG-352 connector; check for solid contact on the threads
and that the centre contact is not broken or loose. Symptoms of a poor connector would be
random fluctuations of reflected power during operation or abnormally high VSWR readings.
The AS-1735/SRC is an integrally constructed piece of equipment. The only replacement part is
the UG-352 connector which must be procured from the manufacturer. If the antenna requires
more extensive repair, it must be returned to the manufacturer for complete replacement or repair
(see contact information in Section 6).
4.4 Preventative Maintenance
On a regular basis, i.e. once a month, the AS-1735/SRC antenna should be visually inspected for
rigidity, cleanliness and general condition. At this time, it is also recommended to remove the
UG-352/U connector to check as to whether or not any moisture has formed inside due to
condensation. If so, the connector should be wiped dry and reconnected.

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5.0 PARTS LIST
5.1 General
A list of parts shipped with the AS-1735/SRC antenna appears in Table 5.1.
A list of optional parts available from the manufacturer appears in Table 5.2.
Table 5.1- Parts supplied with AS-1735/SRC antenna Shipment
Item # Part Number Description Quantity
1 VD-00-00171-1 AS-1735/SRC Antenna 1
2 VTM-01-003 Technical Manual 1
Table 5.2 - Optional Parts available for the AS-1735/SRC antenna
Item # Part Number Description Quantit
y
1 VD-00-00225-2 Extended Feed Line Sections, 12 to 15 inch masts 2

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6.0 QUICK REFERENCE DATA
6.1 General
Manufacturer’s contact information can be found in Section 6.2.
6.2 Manufacturer's Address
Postal address: Shipping address:
Valcom Manufacturing Group, Inc
P.O. Box 603
Guelph, Ontario
Canada
N1H 6L3
Valcom Manufcaturing Group, Inc
175 Southgate Drive
Hanlon Industrial Park
Guelph, Ontario
Canada
N1G 3M5
Or directly at:
Phone : (519) 824 - 3220
Fax : (519) 824 - 3411
e-mail : [email protected]
Internet : www.valcommfg.ca