Shipboard Communication Antenna Systems

Also see 

Shipboard antenna modeling uses brass models in a lead "sea". Receiver probes are inserted from a room underneath the model while test signals are transmitted from the gantry. The model is 1/48 scale and the frequencies used are 48 times higher than actual.

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Antenna detail on CG-10 model
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Antenna detail on CG-10 model
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US Navy photo
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MYSTERY ANTENNA USS Ticonderoga CVA-14 
- please send email if you have additional info

located on starboard side toward stern, aft of elevator
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tilted outboard for flight ops
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from National Archives thanks to Navsource - 1965 Shipyard photo
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Info from Shipyard photo -"XMTR Monopole antenna"

Info from a Ticonderoga ET - "The pickle fork was a multiple whip MHF antenna... It had, if I remember correctly, eight whips on a platform about 10 feet across and mounted on a single pole which could be tilted seaward when launching and recovering aircraft... The whips were all attached to a netting of copper cables which surrounded the base of the platform and electrically lengthened the antennas ..It was fed by ten tuners which were a combination of capacitance and inductance in series and parallel to the antenna, and would also electrically lengthen and shorten the antenna in an attempt to reach the point of resonance..... The radio men would attempt to tune it to a SWR of 1:1 for maximum power out...`the advantage was that if the frequencies had enough split between them, we could put ten transmitters up on a single antenna.."

Typical Ship Antenna Arrangement

USS Mount Whitney LCC-20 Antennas
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USS Iwo Jima LPH-2 Antennas
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Shipyard photos from National Archives thanks to Navsource

USS Bellatrix AKA-3 antennas - 1955
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USS Boxer CVA-21 antennas - 1955
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USS Boxer CVA-21 antennas - 1955
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USS Boxer CVA-21 antennas - 1955
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USS Boxer CVA-21 antennas - 1955
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USS Boxer CVA-21 antennas - 1955
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USS Savage DER-386 antennas - 1957
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USS Essex CVS-9
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USS Allen M. Sumner DD-692
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USS Cassin Young DD-793 1958
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USS Cassin Young DD-793 1958
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USS Samuel Gompers AD-37 1967
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USS Hamner DD-718 1965
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USS Hamner DD-718 1965
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USS Hamner DD-718 1965
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USS Hamner DD-718 1965
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USS Hamner DD-718 1965
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USS Hamner DD-718 1965
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USS Hamner DD-718 1965
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USS Hamner DD-718 1965
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ANTENNA & MULTICOUPLER SYSTEM ON THE DL-2 (1952)

ant-dl2-01.JPG (800176 bytes)The multicoupling system to be installed on a new vessel, the Destroyer Leader DL-2 is shown in Figure 3- 30. The communications system on this ship uses a minimum number of antennas and is designed for maximum flexibility.

There are six antennas used with the multicoupling system: two 35 -foot whips and one wire antenna for receiving, and two 35-foot whips and one flat -top antenna for transmitting. The receiving antennas are located forward and the transmitting antennas are located aft so as to provide the best possible isolation between the two types. Provision is made to use any equipment with any of the antennas (except the flat-top) in the event of failure or damage to certain portions of the ship.

This ship uses three AN/SRA-9 receiving filter assemblies. Two located at the central Receiving Distribution Unit and one at the Auxiliary Distribution Unit.

Three transmitting filter assemblies are located at the Central Transmitting Distribution Unit. One of the filter assemblies, F-159/SRT has a crossover frequency of 375 kc with switching provisions for shifting the crossover frequency to 425 kc; another filter assembly, F-160/SRT has a crossover frequency of 1750 kc; the third filter assembly, F-161/SRT, has a crossover frequency of 3250 kc with provisions for shifting the crossover frequency to 3750 kc.

The three transmitting filter assemblies are stack-mounted. A four-pole, three-gang, Filter Selector Switch is mounted on the rear of the cabinets. The purpose of this switch is to allow both transmitters to be connected to any one of the three filter assemblies or to allow one of the transmitters to be connected directly to the antenna. This permits more versatile use of the transmitting equipments .

Antennas aboard USS Arlington AGMR-2 (thanks to John KX4P)

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HF Communications Antennas

Discone-cage (Discage) Antenna

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Discage Antenna
(USS Wright CC-2)
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Bow Discone-Cage Antenna
(USS Los Angeles CA-135)
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Bow Discone-Cage Antenna aboard USS Iowa BB-61

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DSC02066.JPG (2937008 bytes) USS Iowa BB-61 Discone-cage Antenna Drawings
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The discone-cage antenna is actually two antennas combined into one structure, each antenna having a separate feedpoint. The highband antenna is of the discone type, utilizing an array of radial elements in a horizontal plane at the top of the cage as the disc and the upper section of the cage as the cone. The antenna is fed at the gap between the disc and the apex of the cone. The midband antenna consists of the entire cage section. The lower ends of the wires which form the cage are terminated on a collector ring which is insulated from the grounded supporting structure and used as the feedpoint. Feedpoint impedance-matching networks are required for both sections. A shorted coaxial stub is built into the upper section of the supporting mast for matching the upperband discone antennas to 50-ohm coax. It is occasionally necessary to add a series capacitor in the feedline, depending on antenna configuration details and the influence of antenna siting parameters. The matching network for the cage section is located in a deck-mounted enclosure at the feedpoint.

The discone-cage antenna must be located in a clear area. Adjacent structure will alter its radiation pattern characteristics and feedpoint impedances. One of the most successful locations has been on the bow of ships other than carriers. To avoid interference with anchor-handling requirements, the discage has been successfully installed on a bridge structure erected over the anchor machinery area. In other installations the antenna has been mounted on a pedestal, approximately 7 feet high, to reduce the electrical shock hazard to personnel.

2/2/13 - From USS Missouri - "If you have worked KH6BB onboard the USS Missouri battleship berthed in Pearl Harbor next to the USS Arizona Memorial you know what a thrill it was working this icon of WWII. Our main antenna is/was the discone on the bow which allows us to work so many stations, especially during Museum Ship Weekend in early June.

Well, that discone has been deteriorating over the years, especially its foundation, that the USS Missouri Memorial Association is seriously considering removing it. That would leave KH6BB with only a couple of verticals with which to make contacts. Considering how much better the discone works this would cause a serious decrease in the ability to contact KH6BB.

The members of KH6BB have made arrangements with the memorial association to try and raise funds to restore the discone antenna. The estimate for repairs is $45K along with our time and talent efforts. We are looking for any amounts large or small to keep our signal on the air. More details are available at http://www.ussmissouri.org/ kh6bb . All donations are tax deductible and more details are on the website. DO NOT send any funds to me!"

Shipboard Sleeve Antennas

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Sleeve antennas on USS Northampton CC-1
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CONICAL MONOPOLE ANTENNA
Another broadband antenna used extensively is the conical monopole shown in figure 3-36. Like the sleeve antenna, it is used both ashore and aboard ship. When operating at frequencies near the lower limit of the high-frequency band, the conical radiates in much the same manner as a regular vertical antenna (omnidirectional on the horizontal plane). At the higher frequencies the lower cone section radiates, and the effect of the top section is to push the signal out at a low angle. The low angle of radiation causes the skywave to return to the earth at great distances from the antenna. Hence, the conical monopole antenna is well suited for long distance communication in the high-frequency range.
Shipboard Conical Monopole
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Wire Antennas - Also See wire antenna hardware

Shipboard Wire Antennas
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Bottom-Fed Wire Fan Antenna
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Blueprints of USS North Carolina BB-55 Wire Antennas

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Wire Antennas on USS Texas BB-35
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Top-Fed Wire Fan Antenna

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Matching network (center of photo) for top-fed wire antennas on USS Midway CV-41. Note two feed lines to each 3-wire fan.

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Top-Fed Wire Fan Antennas on FFG-7 class
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FFG-39 showing fan antenna feedwires from matching network (center) to 5-wire insulators (yardarms) to fans
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Top-fed Wire Fan Antenna on USS Los Angeles CA-135
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The twin-wire rope fan antenna is used to induce RF currents on a portion of the superstructure so that the superstructure in effect becomes part of the radiating system. Consequently, the configuration of the superstructure has direct impact on the performance of the twin-fan antenna. Shipboard experience and model measurements have served to identify certain relationships between topside configuration and the performance of fan antennas, but there are, as yet, no rigorous methodologies for designing fan antennas. The present twin-fan antenna has an open-wire feed system which is the most performance-sensitive portion of the installation.

Whip antennas - 

NT-66047 5 section, 35'
NT-66046 4 section, 28'
non-telescoping aluminum whip
more info here

The NT-66047 is a 35-ft aluminum whip antenna composed of five equal lengths of 6061-T6 aluminum tube. 

The lengths are joined together by fitting the adaptor sleeve at the bottom of the upper pieces into the larger diameter lower pieces and securing the joint with a threaded cap and lock nut.

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NT-66047 35' whips aboard USS Midway CV-41 
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Whip Insulators

Mounting insulator for NT-66047 is 
NT-61335 or NT-61350
 (IL-18/U or IL-19/U)
(NL222B31-203 or NL222B32-240)

Whip mount atop insulator
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Base of whips in storage aboard USS Midway CV-41
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NT-66053 is a general purpose 25' non-telescoping whip antenna
weighing 30 lbs. It consists of three sections of stainless steel
tubing which screw together. In shipboard installations, the whip
mounts on Base Insulator NT-61428. In submarines Insulator Type
NT-61664B is used.

Photos in the row below thanks to Tom Hoosac - NT-66047 (with one section shortened)
The NT-66047 is a 35-ft aluminum whip antenna composed of five equal lengths of 6061-T6 aluminum tube. The lengths are joined together by fitting the adaptor sleeve at the bottom of the upper pieces into the larger diameter lower pieces and securing the joint with a threaded cap and lock nut.
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AT-1022/SR - need photo

The AT-1022/SR is a 35-ft fiberglass whip antenna composed of two sections approximately equal in length. 
The antenna is uniformly tapered from an outside diameter at the base of 5-1/2 inch into an outside diameter at the top of 1-1/2 in.

AS-2537/SR
fiberglass 35 ft. whip antenna

NT-66047 was replaced by a 2-section 35' fiberglass whip AS-2537/SR
(see photos at right & below)

The AS-2537 is made in two fiber-glass sections bolted together with an integral mounting base of steel included in the lower section. The radiating portion of the antenna consists of six beryllium-copper strips laminated in fiber glass. In the AS-2537A, the two whip sections screw together and the insulator portion is also fiber glass.

 

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USS Midway CV-41 - 
near whips NT-66047
far whips AS-2537/SR

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AS-2537A/SR 35' fiberglass whip
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AS-2537A/SR 35' fiberglass whip
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AS-2537A/SR 35' fiberglass whip
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AS-2537A/SR 35' fiberglass whip
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Dual-Whip antenna - 

This antenna consists of two AS-2537/SR whips mounted approximately 10 feet apart, tied together at or near their feedpoints, and fed with a single coaxial feedline. The impedance characteristics in a 50-ohm system are greatly improved over those of a single whip. A matching network is required when the antenna is used for transmitting but is optional for receiving. The twin-whip antenna is normally located on top of the pilot house, sometimes tilted 45 degrees towards the bow. The best location is on the centerline.

twin-whip-01.jpg (8618 bytes) Dual-Whip aboard USS Midway CV-41
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AS-4037/SRC twin whip on the fantail of  USS Antietam CG-54 06/07/1987
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Dual-Whip aboard USS Wright CC-2
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Dual-Whip tilting mount aboard USS Midway CV-41
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Trussed Whip Antennas -

The 35-foot trussed whip is an NT-66047 or other type whip which has been broadbanded by the addition of wires around the antenna usually trussed to spokes attached part way up the whip (ref drawing below ). The diameter of the whip is increased to several feet (the diameter will vary) at the spokes with the wires tapering to the whip diameter at the bottom and upper attachment points of the trussing. Trussing improves the efficiency of a whip by lowering the mismatch loss to a 50-ohm system at the lower high frequencies. 

AS-2805/SRC 35' trussed whip
(AS-2807 is the untrussed version)
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35' trussed whip on USS Midway CV-41
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18' trussed whip on USS Midway CV-41
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Trussed Whip base on USS Midway CV-41
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Trussed Whip Antenna aboard USS Iowa BB-61
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USS Iowa BB-61 Trussed Whip Antenna Drawings
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AN/SRA-43 HF Receiving antenna  need photo 2-8 mc receiving antenna and preselector
    AS-1857/SRA-43 Whip (5')
    TN-438/SRA-43 Tuner
    C-6828/SRA-43 Control
0967-269-4010

LF/VLF Communications Antennas

 

AN/SRA-17 LF/VLF antenna group

Components - 
  C-2536B/SRA-17 controller
  TN-344A/SRA-17A tuner 
    or TN-418/SRA-17C tuner
  AT-924B/SR antenna
    or AS-2687/SRA-17D antenna

   need more photos

manual NAVSHIPS 92299

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C-2536B/SRA-17 controller
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AT-924/SR Antenna is 129" long

TN-334 or TN-418 tuner

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AS-2687/SRA-17D Antenna

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130.25" overall

 

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sra17-tn418-1405-04.jpg (24942 bytes) sra17-tn418-1405-03.jpg (13359 bytes) sra17_5348.JPG (3235980 bytes) C-6193/SRA-17 antenna control unit
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The AT-924/SR antenna is an integral part of the TN-334A/ SRA-17C RF tuner. The antenna, tuner, and antenna control unit C-2536/SRA-17 comprise Antenna Coupler Group AN/SRA-17B. Antenna Coupler Group AN/SRA-17C is comprised of AT-924B/SR antenna, TN-418/SRA-17C RF tuner and C-6193/SRA-17 antenna control unit. The AT-924A/SR and AT-924B/SR have equal overall dimensions and are mounted on the same type of base insulator. The configuration and mounting dimensions differ between the TN-334A/SRA-17 and TN-418/SRA-17. Both tuners may be remotely controlled by their respective control units. The antenna coupler groups are physically small but efficient receiving antenna systems for use on small craft where long wires are not available or on ships where large, closely spaced antennas would interact. These antenna groups are designed for use with any receiving equipment tunable over the VLF/LF frequency spectrum.
AN/SRA-28 Loran receiving antenna  need photo Loran receiving antenna NAVSHIPS 94350

VHF/UHF Communications Antennas

AN/SRA-3 VHF whip antenna sra3-01.JPG (314493 bytes)
cu226-sra3-02.JPG (23358 bytes) whip 20-40 mc

NAVSHIPS 91292

AS-2815/SSR Satellite Antenna
(Eggbeater)

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AT-150/SRC UHF antenna

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225-400 mc
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