Vectronics VEC-896 User Manual

VEC-896 Vertical Antenna Instructions

VEC-896 Vertical Antenna

INTRODUCTION

The basic 40 meter quarter wave vertical antenna is 33' tall and requires a reasonably good ground or counterpoise system to function properly. The usual way to eliminate the requirement for a complicated and space consuming ground system is to center feed a 1/2 wave (in this example a 66' tall) antenna.

These problems were solved by combining efficient end loading with a balanced center feedpoint design. The result is a physically small vertical antenna that gives good performance and does not require any type of RF ground system.

The reduction in size is accomplished by adding separate loading coils and capacitance hats at each end of the antenna for the HF bands. The efficient end loading coils are wound on fiberglass forms. The high quality materials and construction of the HF loading system allows a maximum power rating of 1500 watts on 40, 20, 15 and 10 meters. The six and two meter bands are covered with the addition of four quarter wave decoupling stubs on the side of the main elements.

The power rating of this antenna varies from band to band. The PEP ratings are primarily determined be the voltage breakdown of the components, while the CW ratings are generally determined be components heating.

The following chart lists the power rating and the 2:1 VSWR bandwidth of this antenna:

Band Power Bandwidth

CW SSB RTTY

40 m 500 1500 700 40 KHz 20 m 750 1500 1250 250 KHz 15 m 1000 1500 1250 700 KHz 10 m 750 1500 1250 1.0 MHz

6 m 300 750 300 2.6 MHz 2 m 200 300 200 7 MHz

The weight and wind load of this antenna is 15 pounds and approximately 2 square feet respectively.

Warning:

Improper installation and assembly can be hazardous! Read these

instructions thoroughly before attempting to assemble, install or operate this product! High power transmitting devices produce voltages that can cause severe burns or other injuries.

VEC-896 Vertical Antenna Instructions

CHOOSING A LOCATION FOR THE ANTENNA

The best performance on receiving and transmitting will be obtained by mounting the antenna in a clear location above or away from buildings, towers, feedlines, utility wires, and other antennas. While your own ingenuity and particular circumstances will determine the final mounting method, we'll pass along a few ideas for both permanent installation and portable operation.

Warning:

•••• Never mount this antenna in a location that will permit unsuspecting people to come in

contact with the loading spokes or any other part of the antenna.

•••• Never mount this antenna where a mechanical failure might allow the antenna to contact

power lines or other utility wires.

•••• Always ground the feedline at the point where it enters a building to a good earth ground for

lightning protection.

• Always follow the guide lines for antenna installations as recommended by the US consumer

product safety commission.

Always mount this antenna so that it is out of the reach of adults as well as

children. The capacitance elements can cause injury and or severe RF burns.

Permanent Installation

The ideal installation is a rigid pole or roof mount that puts the antenna completely in the clear. If the ideal installation is not possible, choose the best compromise. TV mast or steel water pipe are suitable mast materials. This antenna will mount on masts between 1 and 1-1/2" OD. The use of soft or thin wall masts is not recommended. Never use mast made of soft material or thin wall aluminum, such as aluminum tubing and conduit.

The VEC-896 will perform quite well even at ground level, which means the lower capacitance hat should be at least 5 ft above ground level on a short rigid mast. However, the antenna installation MUST be protected (with non-metallic fencing) to provide personal safety and to prevent damage to the antenna itself.

Portable Operation

This antenna may be disassembled to the extent necessary for transporting to a temporary location. If possible, only remove the two HF loading coil assemblies. Leave the two main elements with the 2 and 6 meter stub assemblies intact. Some retuning may be required after

moving the antenna.

Note: Even for temporary or portable operation, do not be casual about selecting a suitable

mast. If the antenna falls it will be damaged and may cause serious injury. Whatever type of installation you choose, remember that the antenna should be installed where it can never be contacted by people or animals.

VEC-896 Vertical Antenna Instructions

TOOLS AND TIME REQUIRED FOR ASSEMBLY

The estimated assembly time for this antenna is two hours. Antenna assembly requires the following hand tools:

1/4" nut driver 3/8" open end wrench 5/16" nut driver (or 1/4" blade standard screwdriver) 7/16" nut driver 7/16" open end wrench Large wire cutters #1 phillips screwdriver at least 6" long or longer #2 phillips screwdriver suitable eye protection

In addition, you will need two stable supports at least 30" tall (such as saw horses or trash cans) and a short (6-8') temporary mast (1 to 1-1/2" OD) for temporary mounting during tuning.

VEC-896 PARTS LIST

As you unpack your antenna you should find the parts in the following list.

 2 Fiberglass Coil Assemblies  two bundles of wire capacitance spokes 28 short, 12 medium, (and 4 spare long spokes)  one bag of clamps 10 hose clamps and 2 saddle bolts  5' upper radiator, 6061-T6 AL tubing, 1 1/8" OD with the 6 and 2 meter stubs inside  5' lower radiator, 6061-T6 AL tubing, 1 1/8" OD (this tube has two holes through it)  one bag of short 6-32 stainless screws (you will only use 40, the rest are extra)  4 small "L" brackets with holes one end  4 long "U" channel "L" brackets  4 flat fiberglass insulators  2 hollow white nylon insulators  1 solid rod fiberglass center insulator  5 split ring 1/4" washers  5 1/4" dia. 7/16" head bolts  5 1/4-20 x 7/16" nuts  20 6-32 x 1/2" stainless screws  20 6-32 x 1/4" nuts  8 10-32 x 3/8 nuts

For installation you will need some items not supplied with the antenna installation kit.  A 6'-8' rigid mast or other mounting pipe between 1" and 1.5" outside diameter. (suitable

materials include TV mast sections, galvanized iron pipe, or heavy duty rigid conduit.)

VEC-896 Vertical Antenna Instructions

 Quality low-loss 50-Ohm coax with a PL-259 from antenna to transmitter.  Either a SWR meter or Analyzer (such as the Vectronics SWR-584)

SAFETY PRECAUTIONS

Warning:

1. Be careful while climbing and carrying the antenna. It is heavy enough to cause you to lose

your balance if it is handled too casually or if the capacitance spokes are snagged on a gutter, ladder, tree limbs and so forth.

2. Mount the antenna high enough so that it is out of reach. The ends of the capacitance spokes

can cause eye injury, serious RF burns or both.

3. Make sure that the mast is sturdy enough to support the weight (15 pounds) and the wind load

(approximately 2 square feet).

You can be killed if the antenna, feedline, or the equipment used to install the

antenna accidentally contacts any utility lines. Never install an antenna near power lines!

ASSEMBLY and INSTALLATION PROCEDURE

During assembly of this antenna refer to the figures in this manual and the picture on the inside cover. The assembly instructions tell you how to first install the balun and then connect the upper and lower elements. Then the 2 and 6 meter stub elements are installed. Last the loading coil assemblies are assembled and installed on the upper and lower elements.

If you do not wish to install the 6 and 2 meter stubs operation on the other bands will not be affected. Skip step 4, do not install the hose clamps in step 10 and skip steps 13-18.

After the antenna is assembled it is checked and adjusted for resonant frequency and SWR. It can then be mounted on a tower or rooftop and given final adjustments See the Tuning The Antenna section for details.

Note: Wear safety glasses whenever working near or on this antenna.

Warning:

Do not tighten the screws th at connect the loading coil terminal lugs to the

capacitance hats or you will BREAK the fiberglass form. If the terminal lugs loosen tighten the NUT down on the lug.

Step-By-Step Procedure

VEC-896 Vertical Antenna Instructions

 1. Prepare a temporary ground-level mounting mast that will permit easy initial testing and

adjustment. Set up saw horses or any other stable support (plastic trash cans or folding tables, etc.) near the mast.

 2a. Sort out the parts you have unpacked into groups of similar parts. Be sure all the parts are

available.

 3. After examining the antenna parts, gather the tools needed for basic assembly. At the

minimum these consist of:

 #1 Long Phillips screwdriver for capacitance spoke screws

 #2 Phillips screwdriver for other 6-32 screws  1/4" standard screwdriver or a 5/16" nut driver for hose clamps.  3/8" wrench for 6 and 2 meter stub nuts  Two 7/16" open end wrenches or one wrench and one nut driver for "U" BOLTS and

center insulator bolts.

 Wire cutters for trimming capacitance spokes.  Safety glasses.

 4. Assemble the four small "L" brackets to the 4 long fiberglass insulators with the 6-32 x

1/2" screws and the 6-32 x 5/16" nuts as shown in Figure 1.

 5. Bolt the top balun hole loosely to the top hole in the base mounting assembly with a 1/4-

20 x 7/16" nut and the 1/4" x 7/16" head bolts. Use the hollow white nylon spacers to separate the balun from the mounting bracket. Finger tighten only. See Figure 2.

 6. Bolt the bottom balun hole to the bottom hole in the base mounting assembly as in Step 5.

 7. Tighten the balun bolts with a 7/16" wrench.

 8. Bolt the coax connector assembly to the base mounting assembly with four 6-32 x 5/8"

screws and 6-32 nuts. See Figure 2.

VEC-896 Vertical Antenna Instructions

 9. Slide the bottom radiator (the one with two sets of holes) over the fiberglass rod with the

holes that are 2" from the end toward the base mounting bracket. Slide a hose clamp to the bottom of the element. The radiator should butt against the insulating plastic of the base mounting bracket. Install a 1/4 x 7/16" bolt through the element and fiberglass rod and tighten with a lock washer and 1/4 x 7/16" nut.

 10. Slide three more hose clamps over the bottom elem ent. Tighten the hose clamp installed

in step 9 over the slit in the bottom element. This clamp will make the antenna more rigid.

 11. Insert the fiberglass center insulator into the bottom element and insert a 1/4" x 7/16" head

bolt with a lock washer through the hole. Thread a 1/4" x 7/16" nut on the other end. Finger tighten only. See Figure 3. Slide a hose clamp over the center insulator. Tighten the hose clamp on the slit in the bottom element. Slide another hose clamp over the insulator.

 12. Slide the top 1 1/8" diameter element over the center insulator and install the 1/4" x 7/16"

head bolt and nut as in step 10. Tighten the hose clamp over the slit in the top element until the element will not sway.

 13. Slide three hose clamps over the top element.

Note: The upper and lower stubs (U-channel "L" brackets) on each band should not be installed

perfectly in line. There should be enough offset so that the threaded ends won't touch if the stubs are fully shortened. The alignment of the stubs will not affect operation. See Figure 5.

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