Super KitCW Filte r
!
b
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
r
u
o
y
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.
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R
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
5
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!
7
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.
9
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