U, a vertically-polarized omnidirectional antenna having overhead coverage to fill in the cone of silence and operating over a frequency range of 400 through 550 megahertz \(MHz\) for shipboard and shore station applications.

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MIL-DTL-22354C

3.3 Detail requirements.

3.3.1 Functional description. Antenna AT-948/U shall be a two-element dipole colinear array housed within a

polyester fiberglass vapor-tight cylindrical supporting structure. The dipole array shall produce omni-directional

vertically- polarized energy and overhead coverage sufficient to fill in the cone of silence. The mounting flange shall

be an integral part of the fiberglass watertight enclosure.

3.3.2 Overhead coverage. To produce minimum interference with the rest of the pattern and optimum overhead

coverage over the entire frequency region, the upper element of the dipole array shall be designed to provide

orthogonal current distributions so as to fill in the cone of silence overhead.

3.3.3 Dimensions and weight. The AT-948/U shall have a maximum height of 50 inches (1270 mm) and a

nominal diameter of 5.81 inches (147.6 mm). The weight of the complete antenna shall not exceed 25 pounds.

3.3.4 Mounting provisions. The mounting flange base of the AT-948/U Antenna shall be an integral part of the

fiberglass weatherproof housing and shall be a flange 10 inches (254 mm) in diameter and approximately .75-inch

(19.1 mm) thick with an 8.50-inch (215.9 mm) bolt circle on which there are eight .75-inch (19.1 mm) diameter holes

for mounting. The mounting flange shall mate with a standard class 125-type flange.

3.3.5 RF connectors. The rf input to the antenna shall be by means of a connector capable of mating with

connector UG-154A/U (controlling P/N MS91604-154A).

3.3.6 Nomenclature and nameplates. Nomenclature assignment and nameplate approval for equipment

identification shall be in accordance with specification MIL-DTL-18307.

3.4 Workmanship. Antenna and subcomponents shall be manufactured and processed in a careful and

workmanlike manner, with good design and sound engineering and production practice, and to the requirements of

this specification. Antenna shall be free from tool marks, deep scratches, corrosion, and defects that affect life,

serviceability, and appearance.

4. VERIFICATION

4.1 Classification of tests. Equipments shall be subjected to the following tests to determine compliance with all

the applicable requirements.

a. Pre-production tests.

b. Acceptance tests.

4.2 Pre-production tests. Pre-production tests shall be made on one or more equipments representative of the

production equipments to be supplied under the contract. Pre-production tests shall consist of the following:

a. Contractor's demonstration tests.

b. Service approval tests.

4.2.1 Contractor's demonstration tests. Contractor's demonstration tests shall be accomplished under the

responsibility of the contractor and shall be conducted in accordance with the approved test procedure of 4.6. Data

obtained by the contractor in conducting these tests shall be submitted to the acquiring activity for review and

approval prior to shipping the equipment to the specified destination for service approval tests. The Government

Inspector and the acquiring activity shall be advised when tests are to be conducted so that a representative may be

designated to witness or supervise the tests when so desired. Contractors not having adequate facilities to conduct

all required tests shall obtain the service of a commercial testing laboratory satisfactory to the acquiring activity.

4.2.2 Service approval tests. At the completion of the contractor's demonstration tests and when requested by

the acquiring activity, the equipment shall be delivered to a specified government laboratory for additional testing.

This additional testing may consist of duplicating tests previously conducted and such other tests deemed necessary

to determine compliance with all applicable design and performance requirements.