Cushcraft A50-3s Instruction Manual

A50-3S

951364 (12/94)

A50-3S

3 ELEMENT

6 METER BEAM

COMMUNICATIONS ANTENNAS

ASSEMBLY AND INSTALLATION

A50-3S

YourCushcraft6meterbeamisdesignedandmanufacturedtogivetopperformanceandtroublefreeservice. Theantennawillperformasspecified

if the instructions and suggestions are followed and care is used in assembly and installation. When checking the components received in your

antenna package use the parts lists in each section. It is easiest to identify the various dimensions of tubing by separating them into groups of the

same diameter and length. If you are unable to locate any tube or component, check the inside of all tubing. IMPORTANT: save the weight label

from the outside of the carton. Each antenna is weighed at the factory to verify the parts count. If you claim a missing part, you will be asked for

the weight verification label. There is a master parts list on page 2.

LOCATION

Locationoftheantennaisveryimportant. Surroundingobjectssuchastrees,powerlines,otherantennas,etc.willseriouslyreduceefficiency. To

minimize the effects of surrounding objects, mount the antenna as high and in the clear as possible. If metal guy wires are used, they should be

broken with strain insulators. YOU MUST INSURE THAT NEITHER PEOPLE NOR PETS CAN COME IN CONTACT WITH YOUR ANTENNA

WHILEITIS IN OPERATION. DEADLY VOLTAGESANDCURRENTSMAYEXIST. ALSO,SINCE THE EFFECTS OFEXPOSURETORFARE

NOTFULLYUNDERSTOOD,LONGTERMEXPOSURETOINTENSERFFIELDSISNOTRECOMMENDED. THEREISAWARNINGSTICKER

WHICH MUST BE ATTACHED TO THE BOOM AS SHOWN IN FIGURE E.

Plan your installation carefully. If you use volunteer helpers be sure that they are qualified to assist you. Make certain that everyone involved

understands that you are in charge and that they must follow your instructions. If you have any doubts at all employ a professional antenna

installation company to install your antenna.

MOUNTING

The mast mount bracket will accommodate up to a 2" OD (5.1 cm) mast. A 1-1/2" OD (3.8 cm) or larger heavy wall tubing mast should be used.

A good heavy duty antenna rotator will provide the best service and longest life. Often it is desirable to mount several antennas on one mast. To

keep possible interaction to a minimum, place your antennas as far apart as you can.

SYSTEM GROUNDING

Directgrounding oftheantenna, mastandtower isveryimportant. Thisservesasprotectionfromlightningstrikesandstatic buildup,andfrom high

voltage which is present in the radio equipment connected to the antenna. A good electrical connection should be made to one or more ground

rods(orother extensivegroundsystem) directly atthebase of thetoweror mast,usingatleast #10AWG groundwireandnon-corrosive hardware.

For details and safety standards, consult the National Electrical Code. You should also use a coaxial lightning arrester. Cushcraft offers several

different models, such as LAC-1, LAC-2 and the LAC-4 series.

ASSEMBLY

Assembleyourantennabyfollowingthedirectionsandillustrationsinsteps1through5. VerticalpolarizationisnormallyusedFM. Aftertheantenna

is completely assembled, verify dimensions and element spacings for accuracy. Then, return to the section below for final tuning.

TUNING PROCEDURE

The A50-3S does not normally require tuning after assembly. However, if you wish to check the VSWR before installation, please observe the

following procedures. To prevent detuning the antenna, it should be tuned in place or at least 20 feet (6.1 meters) above ground and clear of

surrounding objects. Keep all metal obstructions such as guy wires and other antennas at least 20 feet (6.1 m) away since they will nullify any

adjustment and degraded performance will result.

Runthecoaxcablefromyourtransmittertotheareainwhichtheantennaisgoingtobetested. Thelengthofthiscableoryourfeedlineisnotcritical.

Connect a good quality VSWR bridge to the end of this cable. Connect a short length of cable [10 ft (305 cm) or less] from the VSWR bridge to

theantenna. Set the transmitter to your centeroperating frequency. When you read VSWR, besure you move far enough awayfrom the antenna

so that your body does not effect the reading.

Measure the VSWR. If it is high, move the Reddi-Match clamp (69) by 1/4" (.6 cm) in one direction and check the VSWR. If the VSWR improved,

then continue moving the Reddi-Match clamp in the same direction. If the VSWR deteriorated then move the Reddi-Match clamp in the opposite

direction. Repeat this procedure until no further improvement can be made. You have matched your antenna to 50 Ohms. Then tighten all

connections. Tape the feedline to the mast as shown in figure G.

WARNING

THIS ANTENNA IS AN ELECTRICAL CONDUCTOR. CONTACT WITH POWER LINES CAN RESULT IN DEATH, OR SERIOUS

INJURY. DONOTINSTALL THIS ANTENNA WHERE THERE IS ANY POSSIBILITY OF CONTACTWITHORHIGH VOLTAGE ARC-

OVER FROM POWER CABLES OR SERVICE DROPS TO BUILDINGS. THE ANTENNA, SUPPORTING MAST AND/OR TOWER

MUST NOT BE CLOSE TO ANY POWER LINES DURING INSTALLATION, REMOVAL OR IN THE EVENT PART OF THE SYSTEM

SHOULD ACCIDENTALLY FALL. FOLLOW THE GUIDELINES FOR ANTENNA INSTALLATIONS RECOMMENDED BY THE U.S.

CONSUMER PRODUCT SAFETY COMMISSION AND LISTED IN THE ENCLOSED PAMPHLET.

A50-3S

13 050013 PLASTIC 1-1/4" 2

CAP (3.2 cm)

412 030412 SS WORM 1-3/8" 2

CLAMP (3.5 cm)

KEY P/N DESCRIPTION QUANTITY

MASTER PARTS LIST

Place telescope clamps (412) over the slotted ends of tube AA. Slide BB and CC 3 inches (7.62 cm) into AA so that they butt in the middle.

Tighten clamps and attach end caps (13).

#1 - BOOM ASSEMBLY

KEY P/N DISPLAY DESC SIZE QTY

AA ALUM 1-3/8" X 8" 1

TUBE (3.5 x 20.3 cm)

BB ALUM 1-1/4" x 42" 1

TUBING (3.17 x 106.7 cm)

CC ALUM 1-1/4" x 30" 1

TUBE (3.17 x 76.2 cm)

412

BB CC

72"

(182.9 cm)

Butt ends together.

FIGURE A

9 010009 8-32 x 5/8" (1.59 cm) stainless steel machine screw 2

11 010011 8-32 stainless steel hex nut 3

13 050013 1-1/4" (3.17 cm) plastic cap 2

27 050027 5/8" (1.59 cm) plastic caps 6

32 190032 1-1/2" (3.8 cm) heavy duty U-bolt brackets 3

33 190033 1-1/2" (3.8 cm) U-bolt backing plate 2

69 200069 Formed aluminum tuning strap 1

70 190070 4" x 6" (10.2 x 15.2 cm) formed mast plate 1

84 010084 1/4" (.63 cm) stainless steel lock washer 6

85 010085 1/4" (.63 cm) stainless steel hex nut 6

115 050115 Connector boot 1

116 240116 Silicone package 1

118 010118 5/16" (.8 cm) stainless steel hex nut 8

119 010119 5/16" (.8 cm) stainless steel lock washers 8

326 290326 Danger label 1

402 010402 1-1/2" (3.8 cm) stainless steel U-bolt 3

403 010403 1-5/8" (4.13 cm) stainless steel U-bolt 2

404 010404 2-1/8" (5.4 cm) stainless steel U-bolt 2

409 030409 3/4" (1.9 cm) stainless steel worm clamps 6

412 030412 1-3/8" (3.49 cm)stainless steel worm clamps 2

941 011941 #8 stainless steel internal tooth lock washer 3

AA 1-3/8" x 8" (3.49 x 20.3 cm) aluminum tubing, slotted both ends 1

BB 1-1/4" x 42"(3.17 x 106.7 cm) aluminum tubing 1

CC 1-1/4" x 30" (3.17 x 76.2 cm) aluminum tubing 1

EA 3/4" x 48" (1.9 x 121.9 cm) aluminum tubing slotted both ends, drilled for U-bolt 3

EB 5/8" x 37-1/2" (1.6 x 95.2 cm) aluminum tubing 2

EC 5/8" x 34-1/4" (1.6 x 87.0 cm) aluminum tubing 2

ED 5/8" x 31-1/2" (1.6 x 80.0 cm) aluminum tubing 2

CB Connector bracket 1

RM Reddi Match tube 1

A50-3S

#2 - ELEMENT ASSEMBLY & MOUNTING

(For Vertical or Horizontal Polarization)

FIGURE C

The elements are made up of one pre-drilled and slotted 3/4" (1.9 cm) O.D. center tube and two pre-cut 5/8" (1.59 cm) O.D. end tubes. Assemble

the elements using Figure B for horizontal polarization or Figure B-2 for vertical polarization. Slide the tuning strap (69) on one of the EA tubes.

This will be the driven element #2. Place telescope clamps (409) loosely on the slotted ends of all EA tubes. Note that the EC tubes must be used

with the EA tube on which you placed the tuning strap (69). Attach caps (27) to the end of each element. Mount the elements to the boom (Figure

C). Refer to figure D for mounting the driven element with the connector bracket. Mount the connector with the threads (socket) pointing to the

mast mount. Adjust the antenna to your preferred portion of the 6 meter band using Table 1 if you've chosen horizontal polarization or Table 2 for

vertical polarization. Tighten all connections.

Horizontal Polarization

50 MHz 51 MHz 52 MHz 53 MHz 54 MHz

REF in. 34-1/2 34-1/2 32-1/2 32-1/2 30-1/2

(cm) (87.63) (87.63) (82.55) (82.55) (77.5)

DE in. 31-1/4 30-1/4 29-1/4 28-1/4 27-1/4

(cm) (79.37) (76.83) (74.29) (71.75) (69.21)

D1 in. 28-1/2 26-1/2 26-1/2 26-1/2 24-1/2

(cm) (72.39) (67.31) (67.31) (67.31) (62.23)

Set in. 17 15-5/8 15-3/8 15-1/4 15-1/4

(cm) (43.18) (39.69) (39.05) (38.73) (38.73)

Xin. 4-3/4 4-3/4 4-3/8 4-3/4 4-3/4

(cm) (12.06) (12.06) (11.11) (12.06) (12.06)

Table 1

FIGURE B (Horizontal Polarization)

402

119

118

119

118

ED EA

48"

(121.9 cm)

11"

(27.94 cm)

EB EB

48"

(121.9 cm)

REF

FRONT

(5.1 cm)

27 27

409

409 EC

40"

(101.6 cm)

27.5"

(69.8 cm)

27 27

409 409

#1 - REFLEC

TOR

#2 - DRIV

ELEMEN

#3 - DIRECT

REF

48"

(121.9 cm) D1

326

A50-3S

Vertical Polarization

50 MHz 51 MHz 52 MHz 53 MHz 54 MHz

REF in. 34-1/2 34-1/2 32-1/2 32-1/2 30-1/2

(cm) (87.63) (87.63) (82.55) (82.55) (77.5)

DE in. 31-1/4 31-1/4 31-1/4 29-3/8 28-3/8

(cm) (79.37) (79.37) (79.37) (74.61) (72.07)

D1 in. 28-1/2 28-1/2 26-1/2 26-1/2 24-1/2

(cm) (72.39) (72.39) (67.31) (67.31) (62.23)

Set in. 17 16 17 17-1/2 17-1/2

(cm) (43.18) (40.64) (43.18) (44.45) (44.45)

Xin. 4 3 4-1/4 5-1/2 5

(cm) (10.16) (7.62) (10.79) (13.97) (12.7)

EA ALUM 3/4" x 48" 3

TUBING (1.9 x 121.9 cm)

EB ALUM 5/8" x 37-1/2" 2

TUBING (1.6 x 95.2 cm)

EC ALUM 5/8" x 34-1/4" 2

TUBING (1.6 x 87.0 cm)

ED ALUM 5/8" x 31-1/2" 2

TUBING (1.6 x 80.0cm)

27 050027 PLASTIC 5/8" 6

CAP (1.6 cm)

32 190032 U-BOLT 1-1/2" 3

BRACKET (3.8 cm)

33 190033 BACKING 1-1/2" 2

PLATE (3.8 cm)

69 200069 TUNING 1

STRAP

84 010084 LOCK 1/4" 4

WASHER (.63 cm)

85 010085 HEX 1/4" 4

NUT (.63 cm)

402 010402 U-BOLT 1-1/2" 2

(3.8 cm)

409 030409 SS WORM 3/4" 6

CLAMP (1.9 cm)

KEY P/N DISPLAY DESC SIZE QTY

FIGURE B-2

Vertical Polarization

Table 2

48"

(121.9 cm)

48"

(121.9 cm)

REF

FRONT

EA 2"

(5.1 cm)

409

40"

(101.6 cm)

27.5"

(69.8 cm)

409

REFLECTOR

DRIVEN

ELEMENT

DIRECTOR

REF

48"

(121.9 cm)

326

11"

(27.94 cm)

A50-3S

KEY P/N DISPLAY DESC SIZE QTY KEY P/N DISPLAY DESC SIZE QTY

402 010402 U-BOLT 1-1/2" 1

(3.8 cm)

CB CONNECTOR 1

BRACKET

RM REDDI MATCH 17" 1

ASSEMBLY (41.2 cm)

9 010009 SS MACHINE 8-32 X 5/8" 2

SCREW (1.59 cm)

941 011941 SS LOCK #8 3

WASHER

11 010011 SS HEX 8-32 3

NUT

32 190032 U-BOLT 1-1/2" 1

BRACKET (3.8 cm)

69 200069 TUNING 1

STRAP

84 010084 SS LOCK 1/4" 2

WASHER (.63 cm)

85 010085 SS HEX 1/4" 2

NUT (.63 cm)

FIGURE E

70 190070 MAST MT. 4" X 6" 1

PLATE (10.16 x 15.2 cm)

118 010118 HEX 5/16" 8

NUT (.8 cm)

119 010119 LOCK 5/16" 8

WASHER (.8 cm)

326 290326 DANGER 1

LABEL

403 010403 U-BOLT 1-5/8" 2

(4.13 cm)

404 010404 U-BOLT 2-1/8" 2

(5.4 cm)

#4 - BOOM TO MAST ASSEMBLY

Assemble and mount the mast bracket to the boom centered over the

AA tube. Refer to figure E for assembly.

KEY P/N DISPLAY DESC SIZE QTY

FIGURE D

MAST

118

119

118

119

118 119

404

403

326

After the Reddi-Match tube has

been attached to the driven

element, adjust the angle of the

tuning strap (69) to a point

which brings the Reddi-Match

tube into parallel with the driven

element.

941

11 CB

405

SET

941

NOTE: For vertical polarization

the Reddi-Match assembly

should point skyward.

#3 - REDDI MATCH ASSEMBLY

Slide the Reddi Match tube (RM) through the tuning strap (69). Connect the flattened rod to the screw on the connector (figure D). Slide the poly

tube over the rod up to the flattened end. Adjust to the dimensions shown in Table 1 for horizontal polarization or Table 2 for vertical polarization.

Tighten all connections.

A50-3S

115 050115 CONNECTOR 1

BOOT

116 240116 SILICONE 1

PACKAGE

KEY P/N DISPLAY DESC SIZE QTY #5 - FEEDLINE ASSEMBLY

Beforeattachingthefeedlinepermanently,tunetheantennaasoutlined

onpage2. Theantenna is designed for use with 50 Ohm coaxial cable

terminatedwithaPL-259connector. Anylengthoffeedlinecanbeused

with your A50-3S. The shortest length of cable will have the least loss.

Aconnector boot is included for usewith your new antenna. (Figure F)

Slide the boot over the cable before attaching your PL-259. Coat only

the outside connector threads and shell with silicone grease.

Do not

coatthe center pin or receptacle.

After the PL-259 is firmly screwed on

to the antenna connector, slide the vinyl boot over the connector and

against the mast bracket. When taping the feedline to the mast it's a

good idea to form a drip loop in the coax to help protect the connector

from water damage (figure G).

FIGURE G

cushcraft

COAT WITH SILICONE GREASE

(DO NOT coat the center pin or socket!)

cushcraft

DRIP LOOP

BOOM

SILICONE GREASE

cushcraft

FIGURE F

SPECIFICATIONS

Frequency, MHz

Number Elements

Forward Gain

Front to Back Ratio

SWR Typical

2:1 Bandwidth MHz

Power, Watts PEP

Boom Length

Longest Element

Turning Radius

Mast Size Range

Wind Surface Area

Weight

50-54

8 dBd

20 dB

1.2:1

1000

6 ft. (1.8 m)

117 in. (300 cm)

6 ft. (1.8 m)

1.5-2 in. (3.8-5.1cm)

1.80 ft2. (0.17 m2)

7 lb. (3.2 kg)

48 PERIMETER ROAD, MANCHESTER, NH 03108 • 603-627-7877 / FAX 603-627-1764

COMMUNICATIONS ANTENNAS

SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE

LIMITED WARRANTY

Cushcraft Corporation, P.O. Box 4680, Manchester, New Hampshire 03108, warrants to the original consumer purchaser for one year from date of purchase that each Cushcraft antenna is free

of defects in material or workmanship. If, in the judgement of Cushcraft, any such antenna is defective, then Cushcraft Corporation will, at its option, repair or replace the antenna at its expense

within thirty days of the date the antenna is returned (at purchasers expense) to Cushcraft or one of its authorized representatives. This warranty is in lieu of all other expressed warranties, any

impliedwarrantyislimitedindurationto one year. Cushcraft Corporation shall not be liable for any incidental or consequentialdamageswhichmayresultfrom a defect. Some states do not allow

limitations on how long an implied warranty lasts or exclusions or limitations of incidental or consequential damages, so the above limitation and exclusion may not apply to you. This warranty

givesyouspecificlegalrights,andyoumayalsohaveotherrightswhichvaryfromstatetostate. This warrantydoesnotextendtoanyproductswhichhavebeensubjecttomisuse,neglect,accident