Vectronics VEC-821K User guide

Super KitCW Filte r

wit h 1 Wat t audio amp lifie r

model VEC-821K

shown with optional cabinet

Inc re d ib ly n arrow 8 0 Hz b andwid th le ts y o u pull Morse c o de s igna ls o u t o f hea vy int e rfe re nce o n any ham radio b and. Powe rful o ne wat t aud io amp lifie r d riv e s e xte rnal s p eake r. Eigh t po les o f ac t ive IC filt e ring give s super ste ep CW skirt s fo r p erforman ce t hat fe w tunable filt e rs can mat c h– in te rfere nc e is up t o 6 0 dB down one oc t ave aw ay.

-Razor sharp selectivit y dramaticall y snatches out your desired CW signal from a mass of interference.

-Select from 3 bandwidth: 8 0, 110 , 1 80 H z. Center frequency i s a pleasant 750 Hz.

-15 dB noise reduction relieves fatigue. Automatic noise li miter knocks down static crashes and other i mpulse noises. Plugs into your transceiver’s phone jack. Dri ves external speaker to one watt.

-Requires 9 to 1 8VDC, 3 00 mA

Skill Level 1

Simple: Calls for a few basic tools-

a soldering iron, cutters, plyers, wi re strippers, and a small screw driver. Does not require test

equipment for final adjustment or tuni ng.

i d

VECTRONICS

High-performanc e e lectro n ic k it s ... fun t o build and use!

IMPORTANT WARRANTY INFORMATION! PLEASE READ

Return Policy on Kits When Not Purchased Directly From Vectronics: Before

continuing any further with your VEC kit check with your Dealer about their return policy. If your Dealer allows returns, your kit must be returned before you begin construction.

Return Policy on Kits When Purchased Directly From Vectronics: Your VEC kit may be returned to the factory in its pre-assembled condition only. The reason for this stipulation is, once you begin installing and soldering parts, you essentially take over the role of the device's manufacturer. From this point on, neither Vectronics nor its dealers can reasonably be held accountable for the quality or the outcome of your work. Because of this, Vectronics cannot accept return of any kit-in-progress or completed work as a warranty item for any reason whatsoever. If you are a new or inexperienced kit builder, we urge you to read the manual carefully and determine whether or not you're ready to take on the job. If you wish to change your mind and return your kit, you may--but you must do it before you begin construction, and within ten (10) working days of the time it arrives.

Vectronics Warrants: Your kit contains each item specified in the parts list.

Missing Parts: If you determine, during your pre-construction inventory, that any part is

missing, please contact Vectronics and we'll send the missing item to you free of charge. However, before you contact Vectronics, please look carefully to confirm you haven't misread the marking on one of the other items provided with the kit. Also, make certain an alternative part hasn't been substituted for the item you're missing. If a specific part is no longer available, or if Engineering has determined that an alternative component is more suitable, Vectronics reserves the right to make substitutions at any time. In most cases, these changes will be clearly noted in an addendum to the manual.

Defective Parts: Today's electronic parts are physically and electrically resilient, and defective components are rare. However, if you discover an item during your preconstruction inventory that's obviously broken or unserviceable, we'll replace it. Just return the part to Vectronics at the address below accompanied with an explanation. Upon receipt, we'll test it. If it's defective and appears unused, we'll ship you a new one right away at no charge.

Missing or Defective Parts After You Begin Assembly: Parts and materials lost or damaged after construction begins are not covered under the terms of this warranty. However, most parts supplied with VEC kits are relatively inexpensive and Vectronics can replace them for a reasonable charge. Simply contact the factory with a complete description. We'll process your order quickly and get you back on track.

Factory Repair After You Begin Assembly: Kits-in progress and completed kits are specifically excluded from coverage by the Vectronics warranty. However, as a service to

customers, technicians are available to evaluate and repair malfunctioning kits for a minimum service fee of $18.00 (½ hour rate) plus $7.00 shipping and handling (prices subject to change). To qualify for repair service, your kit must be fully completed, unmodified, and the printed circuit board assembled using rosin-core solder. In the event your repair will require more than an hour to fix (or $36.00, subject to change), our technicians will contact you in advance by telephone before performing the work. Defective units should be shipped prepaid to:

Vectronics 1007 HWY 25 South Starkville, MS 39759 When shipping, pack your kit well and include the minimum payment plus shipping and handling charges ($25.00 total). No work can be performed without pre-payment. Also, provide a valid UPS return address and a day time phone number where you may be reached.

TABLE OF CONTENTS

Introduction 5

Tools and Supplies............................................................................... 5

Before You Start Building ..................................................................... 6

Soldering Tips: ............................................................................. 6

Desoldering Tips: ......................................................................... 7

Work Habits: ................................................................................ 7

Sorting and Reading Resistors:.................................................... 8

Reading Capacitors:..................................................................... 8

Diodes: ......................................................................................... 9

Transistors: .................................................................................. 9

Integrated Circuits: ....................................................................... 10

Parts List .............................................................................................. 11

Parts Placement Diagram .................................................................... 12

Step-By-Step Assembly........................................................................ 12

Phase 1: ....................................................................................... 13

Phase 2: ....................................................................................... 15

Phase 3: ....................................................................................... 17

PC Board Inspection: ................................................................... 20

Testing and Alignment.......................................................................... 20

Operating Instructions .......................................................................... 21

Receiver or Scanner Operation.................................................... 21

In Case of Difficulty .............................................................................. 22

No Signal Filtering:....................................................................... 22

Intermittent Filter Operation: ........................................................ 22

Filter Stops Filtering: .................................................................... 23

No Speaker Audio: ....................................................................... 23

Theory of Operation and Specifications ............................................... 23

Circuit Description: ....................................................................... 23

Specifications: .............................................................................. 23

Enclosure ............................................................................................. 23

Schematic............................................................................................. 23

VEC-821K Instruction Manual Super CW Filter Kit

INTRODUCTION

Thank you for purchasing the VEC-821K CW Filter kit. The VEC-821K consists of a four stage, switch selectable band pass CW filter, using selected components that will make “cleaning up” CW signals effortless and easy. Featuring razor sharp selectivity and extremely steep sided skirts, even the weakest signal stands out. Also, the VEC-821K has a 1 watt audio amplifier built in that will easily drive headphones or an external speaker. With the VEC-821K you bring up any hard to hear signal out of a “band pile up” for easy listening or get rid of unwanted, annoying signals. The VEC-821K also features a headphone output that will allow the use of standard monoral headphones. Although physically small in size, the VEC-821K is high on performance and reliability. The VEC-821K is powered from a 9-volt transistor radio battery, or any 9-18 volt DC power supply.

TOOLS AND SUPPLIES

Construction Area: Kit construction requires a clean, smooth, and well-

lighted area where you can easily organize and handle small parts without losing them. An inexpensive sheet of white poster board makes an excellent construction surface, while providing protection for the underlying table or desk. Well-diffused overhead lighting is a plus, and a supplemental high-intensity desk lamp will prove especially helpful for close-up work. Safety is an important consideration. Be sure to use a suitable high-temperature stand for your soldering iron, and keep the work area free of combustible clutter.

Universal Kit-building Tools: Although your particular kit may require additional items to complete, virtually all construction projects require a work area outfitted with the following tools and supplies:

 30-60 watt Soldering Iron  High-temperature Iron Holder with a Moist Cleaning Sponge  Rosin-core Solder (thin wire-size preferred)  Needle Nose Pliers or Surgical Hemostats  Diagonal Cutters or "Nippy Cutters"  Wire Strippers  Solder Sucker, Vacuum Pump, or Desoldering Braid  Bright Desk Lamp  Magnifying Glass

BEFORE YOU START BUILDING

Experience shows there are four common mistakes builders make. Avoid these, and your kit will probably work on the first try! Here's what they are:

1. Installing the Wrong Part: It always pays to double-check each

step. A 1K and a 10K resistor may look almost the same, but they may act very differently in an electronic circuit! Same for capacitors--a device marked 102 (or .001 uF) may have very different operating characteristics from one marked 103 (or .01uF).

2. Installing Parts Backwards: Always check the polarity of electrolytic

capacitors to make sure the positive (+) lead goes in the (+) hole on the circuit board. Transistors have a flat side or emitter tab to help you identify the correct mounting position. ICs have a notch or dot at one end indicating the correct direction of insertion. Diodes have a banded end indicating correct polarity. Always double-check-especially before applying power to the circuit!

3. Faulty Solder Connections: Inspect for cold-solder joints and solder

bridges. Cold solder joints happen when you don't fully heat the connection--or when metallic corrosion and oxide contaminate a component lead or pad. Solder bridges form when a trail of excess solder shorts pads or tracks together (see Soldering Tips below).

4. Omitting or Misreading a Part: This is easier to do than you might

think! Always double-check to make sure you completed each step in an assembly sequence.

Soldering Tips:

Cleanliness and good heat distribution are the two secrets of professional soldering. Before you install and solder each part, inspect leads or pins for oxidation. If the metal surface is dull, sand with fine emery paper until shiny. Also, clean the oxidation and excess solder from the soldering iron tip to ensure maximum heat transfer. Allow the tip of your iron to contact both the lead and pad for about one second (count "one-thousand-one") before feeding solder to the connection. Surfaces must become hot enough for solder to flow smoothly. Feed solder to the opposite side of the lead from your iron tip--solder will wick around the lead toward the tip, wetting all exposed surfaces. Apply solder sparingly, and do not touch solder directly to the hot iron tip to promote rapid melting. If you are using Lead free solder it has a higher melting point than the older Tin-Lead solder. Make sure you allow the lead and pad to get hot enough for the solder to flow properly. DO NOT USE ACID CORE SOLDER.

When cutting and bending leads make sure they do not short between adjacent pads on the board.

VEC-821K Instruction Manual Super CW Filter Kit

Good

Not Good

Desoldering Tips:

If you make a mistake and need to remove a part, follow these instructions carefully! First, grasp the component with a pair of hemostats or needle-nose pliers. Heat the pad beneath the lead you intend to extract, and pull gently. The lead should come out. Repeat for the other lead. Solder may fill in behind the lead as you extract it-especially if you are working on a double-sided board with plate-through holes. Should this happen, try heating the pad again and inserting a common pin into the hole. Solder won't stick to the pin's chromium plating. When the pad cools, remove the pin and insert the correct component. For ICs or multi-pin parts, use desoldering braid to remove excess solder before attempting to extract the part. Alternatively, a lowcost vacuum-bulb or spring-loaded solder sucker may be used. Parts damaged or severely overheated during extraction should be replaced rather than reinstalled.

Work Habits:

Kit construction requires the ability to follow detailed instructions and, in many cases, to perform new and unfamiliar tasks. To avoid making needless mistakes, work for short periods when you're fresh and alert. Recreational construction projects are more informative and more fun when you take your time. Enjoy!

Sorting and Reading Resistors:

The electrical value of resistors is indicated by a color code (shown below). You don't have to memorize this code to work with resistors, but you do need to understand how it works:

Resistor Color Code

Black = 0 (tens) 1st Digit 2nd Digit Multiplier

Tolerence

(gold or silver)

When you look at a resistor, check its multiplier code first. Any resistor with a black multiplier band falls between 10 and 99 ohms in value. Brown designates a value between 100 and 999 ohms. Red indicates a value from 1000 to 9999 ohms, which is also expressed as 1.0K to 9.9K. An orange multiplier band designates 10K to 99K, etc. To sort and inventory resistors, first separate them into groups by multiplier band (make a pile of 10s, 100s, Ks, 10Ks, etc.). Next, sort each group by specific value (1K, 2.2K, 4.7K, etc.). This procedure makes the inventory easier, and also makes locating specific parts more convenient later on during construction. Some builders find it especially helpful to arrange resistors in ascending order along a strip of double-sided tape.

Some VEC kits may contain molded chokes which appear, at first glance, similar to resistors in both shape and band marking. However, a closer look will enable you to differentiate between the two--chokes are generally larger in diameter and fatter at the ends than resistors. When doing your inventory, separate out any chokes and consult the parts list for specific color-code information.

Brown = 1 (hundreds)

Red = 2 (K)

Orange = 3 (10K)

Yellow = 4 (100K)

Green = 5 (1Meg)

Blue = 6 Violet = 7 Gray = 8 White = 9 Silver = 10% Gold = 5%

Reading Capacitors:

Unlike resistors, capacitors no longer use a color code for value identification. Instead, the value, or a 3-number code, is printed on the body.

VEC-821K Instruction Manual Super CW Filter Kit

Value Code

10 pF = 100 100 pF = 101 1000 pF = 102

.001 uF = 102*

.01 uF = 103 .1 uF = 104

As with resistors, it's helpful to sort capacitors by type, and then to arrange them in ascending order of value. Small-value capacitors are characterized in pF (or pico-Farads), while larger values are labeled in uF (or micro-Farads). The transition from pF to uF occurs at 1000 pF (or .001 uF)*. Today, most monolithic and disc-ceramic capacitors are marked with a three-number code. The first two digits indicate a numerical value, while the last digit indicates a multiplier (same as resistors).

Electrolytic capacitors are always marked in uF. Electrolytics are polarized devices and must be oriented correctly during installation. If you become confused by markings on the case, remember the uncut negative lead is slightly shorter than the positive lead.

Multilayer

(270 pF)

271

Ceramic Discs

(.001 uF) (.1 uF)

102

104

Electrolytic

1 uF

1uF

35V

Diodes:

Diodes are also polarized devices that must be installed correctly. Always look for the banded or cathode end when installing, and follow instructions carefully.

Cathode

(shorter Lead)

Diode

LED

Transistors:

If transistors are installed incorrectly, damage may result when power is applied. Transistors in metal cases have a small tab near the emitter lead to identify correct positioning. Semiconductors housed in small plastic cases (TO-92) have an easily-identified flat side to identify mounting orientation. Many specialized diodes and low-current voltage regulators also use this type packaging. Larger plastic transistors and voltage regulators use a case backed with a prominent metal tab to dissipate heat (T-220). Here orientation is indicated by the positioning of the cooling tab.

Metal Can Device Plastic Device Tab-cooled Device

Emitter

Flat Side

Metal Tab

Integrated Circuits:

Proper IC positioning is indicated by a dot or square marking located on one end of the device. A corresponding mark will be silk-screened on the PC board and printed on the kit's parts-placement diagram. To identify specific IC pin numbers for testing purposes, see the diagram below. Pin numbers always start at the keyed end of the case and progress counter-clockwise around the device, as shown:

8 7 6 5

Installation

Key

1 2 3 4

Pin Numbers

Installation

Key

VEC-821K Instruction Manual Super CW Filter Kit

PARTS LIST

Your kit should contain all of the parts listed below. Please go through the parts bag to identify and inventory each item on the checklist before you start building. If any parts are missing or damaged, refer to the warranty section of this manual for replacement instructions. If you can't positively identify an unfamiliar item in the bag on the basis of the information given, set it aside until all other items are checked off. You may then be able to identify it by process of elimination. Finally, your kit will go together more smoothly if parts are organized by type and arranged by value ahead of time. Use this inventory as an opportunity to sort and arrange parts so you can identify and find them quickly.

Qty Part Description Designation





1 2.7 ohm resistor (red-violet-gold) R17



1 5.6 ohm, 1/2 watt resistor (green-blue-gold) R19



1 1K ohm resistor (brown-black-red) R2



1 1.8K ohm resistor (brown-gray-red) R1



6 24.3K* ohm resistor (red-yellow-orange-red)



1 91K ohm resistor (white-brown-orange) R3



4 681K* resistor (blue-gray-brown-orange) R4,R7,R11,R18



4 1.82M* ohm resistor (brown-gray-red-yellow) R6,R9,R12,R16



6 .1uF disc ceramic capacitor (104 or 104Z)



1 .01uF disc ceramic capacitor (103Z) C8



8 1000 pF poly capacitor (1000J)



2 470uF electrolytic capacitor (470uF) C1,C9



2 10uF electrolytic capacitor radial (10uf) C10,C11



2 CDHS270 diode (CDHS270) D1,D2



2 LM747 Op Amp IC U1,U2



1 LM380 Audio Amplifier (LM380) U3



3 14 pin IC sockets For U1,U2,U3



1 Rotary Switch SW1



1 Switch PCB (861-1565) For SW1



2 8 pin right angle headers For SW1



1 3/8-32 Hex Nut For SW1



1 Thin Flat Steel Washer For SW1



4 6” insulated wires For circuit wiring



1 9-volt battery snap



1 PC board VEC-821K



1 Owner's Manual

* These parts have a 1% tolerance. The fifth color band on these components will be BROWN,

R5,R8,R10,R13, R14,R15

C2,C3,C4,C5, C6,C7

C12,C13,C14, C1,C5,C16,C17, C1,C8,C19

specifying a 1% tolerance.

PARTS PLACEMENT DIAGRAM

Figure 1

STEP-BY-STEP ASSEMBLY

Before assembling your kit, please take time to read and understand the VEC kit warranty printed on the inside cover of this manual. Also, read through the assembly instructions to make sure the kit does not exceed your skill level. Once you begin construction, your kit will be nonreturnable. Finally, if you haven't already done so, please verify that all parts listed in the inventory are included. If anything is missing or broken, refer to the warranty instructions for replacing missing or damaged parts.

Note that part designators, such as R1, C3, etc., appear on a silkscreened legend on the component-mounting side of the printed circuit board. This corresponds with the parts placement page in the manual. All parts will be inserted on the silk-screen side of the board.

If you have last-minute questions about what you need to build your kit, please refer back to the section titled "Tools and Supplies". If you're ready to begin now, here we go!

The directions use two sets of check boxes. Check one when a step is complete and use the other for double-checking your work before operation.

VEC-821K Instruction Manual Super CW Filter Kit

.4"

Phase 1:

  1. Locate resistor R1. This is 1.8K resistor (brown-gray-red).

Carefully bend the leads close to the resistor body to form right-angles (see following diagram).

  2. Insert R1 into its mounting holes so the resistor body rests