Procom TWA 1 - Manual

TWA 1
Broadband Transformer for Marine Wire Receiving Antennas
DESCRIPTION
Together with a wire receiving antenna this passive matching
transformer provides a very efficient means of establishing a wideband
50 Ω receiving antenna system for the complete LF, MF and HF range.
A typical installation can be seen on the figure below. The wire antenna
is suspended with both ends insulated between two high points on the
ship. The TWA 1 is mounted in immediate vicinity of one of the
suspension points, and the antenna terminal of the TWA 1 is connected
to the wire antenna.
The TWA 1 can be mounted on vertical or horizontal mast tubes, 30–54
mm in outer diameter and it can operate together with wire antennas
with a length between 5 and 10 meters.
The frequency compensated transformer converts the widely varying
antenna impedance to a constant 50 Ω, making it possible to use length-
independent, shielded, standard RG 58 C/U or RG 213/U as downlead
cable to the 50 Ω receiver.
For proper performance of the antenna system the separate earth
terminal on the transformer must be connected to the mounting tube,
and this mounting tube must be connected to the earth potential of the
ship.
This earthing procedure ensures a low-loss connection to ground for RF-
signals and prevents noise pick-up from the ship’s installations, running
on the outside of the coaxial cable, in being coupled on-frequency to the
wire antenna. As the earth terminal is AC-coupled, electrolytical
corrosion is effectively prevented.
The transformer and the 50 Ω receiver are protected against RF
overload and violent discharges by an air spark gap (approx. 1 kV), a
gas filled spark gap (90 V) and a resistance network.
The transformer unit with protection circuits is built into a watertight
UV-resistant polycarbonate box and, moreover, all circuitry is totally
encapsulated in polyurethane sealer. The mounting plate as well as all
accompanying fittings are made of stainless steel.
ORDERING DESIGNATIONS
TYPE NO. PRODUCT NO.
TWA 1 110000113
SPECIFICATIONS
ELECTRICAL
MODEL TWA 1
TYPE Broadband matching transformer for marine
wire
receiving antennas
FREQUENCY RANGE 100 kHz – 30 MHz
OUTPUT IMPEDANCE Nom. 50 Ω
MIN. LENGTH OF WIRE
ANT.
5 m
MAX. LENGTH OF WIRE
ANT.
10 m
MECHANICAL
TEMP. RANGE -30° C → +70° C
CONN. TO ANTENNA M8 thread stud
CONN. TO EARTH M6 thread stud
CONN. TO DOWNLEAD N-female
COLOUR Light-grey
METERIALS Clamps : Stainless steel
Housing: Polycarbonate
WIDTH 95 mm
HEIGHT 100 mm
DEPTH 38 mm
WEIGHT Approx. 450 g
MOUNTING On vertical or horizontal mast tubes
30–54 mm in outer dia.
PLEASE NOTE
The antenna terminal on the TWA 1 is not dimensioned to carry the 1.
pull from the antenna wire directly. The tension of the antenna wire
must be relieved at a well insulated point before it is connected to the
TWA 1.
If the receiving range is restricted to 8 MHz and below, the wire
2.
antenna can advantageously be extended up to a length of 40 m.
PROCOM A/S reserve the right to amend specifications
without prior notice.
09/11/11