User's Manual

GENERAL INFORMATION
PUB07-07 Rev 2 2
2 PREFIX NUMBERS
Prefix Numbers assist in identifying assemblies and subassemblies by their physical location in the overall transmitter
model assembly. Each transmitter model has an associated Prefix List, which provides an index of Prefix Numbers
identifying the Sub-Assemblies in each Cabinet and in large assemblies.
Every sub-assembly of the transmitter on its own is identified by a nine-digit assembly number (e.g., 21B1234G1). This
assembly number accurately identifies the item, but bears no information on its own regarding its place in the
transmitter and can be cumbersome when identifying functional blocks for documenting the transmitter. To assist in
this matter, the Prefix Numbering of subassemblies indexes the major components into their related cabinets and into
groups of related assemblies. The following paragraphs are adapted from LARCAN Document Number 11A1886,
which outlines the basic system of Prefix Identification
A label attached in the most visible location identifies large Assemblies. Cabinets have labels attached to the
rear, top of cabinet frame. Other Large Assemblies have labels attached in the front.
Cx Control Cabinet # x
Ax Amplifier Cabinet # x
Tx Traplexer # x
Fx Filter # x
Px Patch Panel # x
Ox Optional Assembly # x
Ex Exciter # x
Mx Modulator # x
Ux Upconverter # x
Sx Switch (coaxial, contactless etc.) # x
Lx Load RF # x
CRx Combiner # x
Dx Directional Coupler/Probe Section # x
Xx External components (heat exchanger, power supply, AC distribution panel) # x
Major Subassemblies inside cabinets or on other large assemblies are identified by numbers only, which are
multiples of 10. For example:
10 Contactor Panel
20 AC Distribution Panel
30 Power Amplifier Housing
40 Control Unit
Small Subassemblies inside a major subassembly are identified by integer numbers other than multiples of 10. For
example:
21 PC Board # 1 in AC Distribution Panel
22 PC Board # 2 in AC Distribution Panel
Individual component identification is possible at every level. Labeling clearly with a single label does physical
identification. Only Large Assemblies will have label “Xn” (X=Letter, n=number) or "X". All other assemblies and
components shall have label “n” (n is a number). Each “Xn” or “X” has a square frame outline to denote that it is a
prefix number. No "PFX" or "PREFIX" indication is required in front of the x or xnn. For a PC Board having an overall
prefix number of A2-11 (as indicated on a Running List or Wiring Diagram), the label on the PC Board need only say
11 since the large assembly is to be clearly labeled as A2.