Section I
Introduction/Specifications
1.1
Introduction
The DX-25U Medium Wave Transmitter is a 25 kW transmitter
that is designed to be able to be upgraded quickly to a 50 kW unit
(thus becoming a DX-50 Transmitter). This upgrade requires
very little time and the newly configured system would be back
in operation at the new power level in a minimum of time.
1.1.1
Scope and Purpose
This technical manual contains the information necessary to
install and maintain the DX-25U MEDIUM WAVE TRANS-
MITTER. The various sections of this technical manual provide
the following types of information.
a. Section I, Introduction/Specifications, provides introduction to
technical manual contents.
b. Section II, Installation/Initial Turn-on, provides detailed
installation procedures and initial turn on instructions.
c. Section III, Operators Guide, provides identification and
functions of panel and board mounted controls and indica-
tors as well as of components located in the interior of the
transmitter.
d. Section IV, Overall System Theory, provides a block dia-
gram description of the overall transmitter and operation
of the various sections of the transmitter not covered in
later sections.
e. Section V, Maintenance, provides preventive and corrective
maintenance information as well as alignment procedures.
f. Section VI, Troubleshooting, provides a listing of the pro-
tection devices in the transmitter as well as low power and
high power troubleshooting procedures.
g. Section VII, Parts List, provides an itemized parts list for
individual transmitter modules and the overall transmitter.
h. SECTION VIII, Diagrams
i. The following sections provide principles of operation for
boards and modules in the DX-25U TRANSMITTER:
•
Section A, Oscillator (A17)
•
Section B, Buffer Amplifier (A16)
•
Section C, RF Amplifier Modules (A101-A244)
•
Section D, Driver Combiner/Motherboard (A14)
•
Section E, Driver Supply Regulator (A22)
•
Section F, RF Multimeter (A23)
•
Section G, RF Combiners: Binary Combiner/Motherboard
(A19) and Main Combiner/Motherboard (A2 through A4)
•
Section H, Output Sample Board (A26) and Output Moni-
tor (A27)
•
Section J, Analog Input Board (A35)
•
Section K, Analog To Digital Converter (A34)
•
Section L, Modulation Encoder (A37)
•
Section M, DC Regulator (A30)
•
Section N, External Interface (A28)
•
Section P, Controller (A38)
•
Section Q, LED Board (A32)
•
Section R, Switch Board/Meter Panel (A31)
•
Section S, Driver Encoder/Temperature Sense Board (A19)
j. Appendix A, Lightning Protection Recommendation, pro-
vides information on environmental hazards and possible
steps to minimize their effects.
1.2
Equipment Description
The DX-25U is a solid state medium wave amplitude modulated
transmitter with a rated output power level of 25 kW. The
transmitter is capable of 30 kW and has three user-set power
levels. The frequency range is from 531 kHz to 1605 kHz.
1.3
Block Diagram
A Block Diagram description is contained in Section IV, Overall
System Theory.
1.4
Specifications
The brochure at the end of the manual gives specifications for
the DX-25U transmitter.
NOTE
Harris maintains a policy of continuous improvements on its
equipment and therefore reserves the right to change specifica-
tions without notice.
Rev. R: 11-11-96
888-2297-002
1-1
WARNING: Disconnect primary power prior to servicing.
