MIL-STD-188-140A

Abstract

This standard establishes minimum performance requirements in the form of Technical Design Standards and Design Objectives (D.O.) that will ensure interoperability of future radio subsystems equipment in the VLF and LF bands. Performance requirements for experimental or developmental extremely low frequency (ELF) and ultra low frequency (ULF) are not addressed. The frequency ranges of military communications equipment have been established as a result of band characteristics which do not necessarily depend upon administrative or technical frequency band definitions. For example, in the area of the electromagnetic spectrum above ELF, that portion of application to military broadcast communications is found between 14 kHz and 200 kHz. This portion in fact extends into both the VLF and LF bands. Efficient use of the limited bandwidth available at these lower frequencies precludes most analog modulation techniques. This standard, therefore applies primarily to those radio communications equipment and systems which are involved in the transmission of single and multi-channel teletypewriter, data and facsimile information. <br>This standard shall be used in the design and engineering of new communications equipment for both long haul and tactical systems. Reference is made, in some cases, to other documents which provide standards for specific applications. It is not intended that existing systems be immediately converted in compliance with the requirements of this standard. New systems and those undergoing major modification or rehabilitation shall conform to these standards, subject to the provisions of current procurement regulations. Modulation techniques are not standardized in this document. However, radio subsystems covered by this standard shall be interoperable using any of the modulation methods outlined in Appendix A. <br>Mandatory equipment parameters or requirements within the context of DOD 4640.11 of 21 December 1987 are identified through the use of the word "shall". Desirable or recommended DO's are indicated within parentheses after a mandatory parameter value or by use of the word "should". <b><u>Intended Use:</u></b> This standard contains requirements to ensure interoperability and minimum performance of new VLF and LF radio subsystems. These subsystems are intended for use in tactical and long-haul, shore-to-ship, point-to-point, ground-air-ground and air to ship communication of single and multi-channel teletypewriter, data and facsimile information. This standard is not intended for use in specifications for VLF or LF time standards, navigation systems, special purpose integrated communication systems or terminal equipment external to interface A in <a>FIGURE 1</a>. However, technical design standards for special purpose communication systems should not be less than specified herein without an exemption. <br>