Vectronics VEC-131K User Manual

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 i nsta lli ng a nd sol deri ng pa rt s, you essenti al ly tak e over the rol e of the devic e's manufacturer . From this point on, neither Vect ronics nor its dea lers can reas onably be held accountab le for the qua lity 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 b uilder, we urge you to read the manual carefully a nd determine whether or not you're r eady to tak e on the job. If you wish to c hange your mind and return your ki t, you may--b ut you must do i t before you begin c ons tr uc ti on, a nd 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 Vect ronic s, please look carefully to c onf ir m you haven't misr ea d 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 a re r a re. However, if you disc over a n it em duri ng your pr e- c onst r uct i on 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 defec tive and appear s 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 trac k.

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, tec hnicia ns ar e availa ble t o evaluate a nd repai r malf unctioni ng 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 fi x (or $36.00, subject to change), our technicians will contact you in advance by telephone b efore p erforming t he work. Def ective unit s should b e shipp ed prep aid 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 a nd a day time phone number where you may be reac hed.

VEC-131K Owner's Manual Aircraft Receiver Kit

INTRODUCTION

Imagine climbing into the cockpit and experiencing first-hand how pilots and airtraffic controllers work together to keep our skies safe. Open the door to exciting aviation action; let the VEC-131K be your key to easily intercepting air-comms 100 or more miles distant! Track the progress of incoming and outgoing traffic in your area, hear advanced weather information firsthand from pilot reports (PIREPS), and discover how the National Air Traffic System really works. The VEC-131K is not only fun to build and operate, it’s also a great way to learn about radio-electronics and aviation!

When it comes to pulling in weak signals, the VEC-131K rivals many commercially built aircraft transceivers. Its electronic tuning control covers only those frequencies used for aviation voice communications--118 to 136 MHz. The VEC-131K consumes minimal electrical current and can run for hours from its self-contained 9-volt flat-pack alkaline battery. Plug in a 8-ohm speaker or use headphones for loud-and-clear reception.

The VEC-131K is a single-conversion Superhet featuring a sensitive LNA front end and a varactor-tuned oscillator providing frequency coverage from 118 to 136 MHz. Zener diode regulation keeps the frequency control stable, even when battery voltage is low. A 10.7-MHz ceramic IF filter is also included. Four modern integrated circuit (IC) devices keep construction simple, on a PC board measuring a mere 3 x 3.25”. Whether monitoring exchanges between distant ground statio ns or strong over head air craft, the a udio remains le vel thanks to a n advanced-design Automatic Gain Control (AGC) system.

VEC-131K Owner's Manual Aircraft Receiver Kit

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 and provides protection for the underlying table or desk. Well-diffused overhead lighting is a plus, and a supplemental high-intensity desk lamp is especially helpful for close-up work. Safety is always important! 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 for completion, virtually all construction projects require a work area outfitted with the following tools and supplies:

30 to 60 Watt Soldering Iron (grounded-tip and temperature-controlled

preferred)

High-temperature Iron Holder with Moist Cleaning Sponge

Rosin-core Solder (thin wire size preferred, .031”)

Needle Nose Pliers or Surgical Hemostats

Diagonal Cutters or "Nippy Cutters"

Solder Sucker (squeeze or vacuum pump type), or Desoldering Braid

Bright Desk Lamp

Magnifying Glass

Special Tools for This Kit:

“Blade” type alignment tool

“Hex” tuning tool

VEC-131K Owner's Manual Aircraft Receiver Kit

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:

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:

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:

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 Solder Tips below).

4. Omitting or Misreading a Part:

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.

It always pays to double-check each step. A 1K

Always check the polarity of electrolytic

Inspect for cold-solder joints and solder

This is easier to do than you might think!

Desoldering Tips:

VEC-131K Owner's Manual Aircraft Receiver Kit

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 ho les. Should this happen, try heating the p ad 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 low-cost vacuum-bulb or springloaded 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

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%

VEC-131K Owner's Manual Aircraft Receiver Kit

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. (No chokes are used in the VEC-131K.)

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.

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.

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.

Multilayer

(270 pF)

271

Ceramic Discs

(.001 uF) (.1 uF)

102

104

Electrolytic

1 uF

1uF

35V

Diode

Cathode

(shorter Lead)

LED

VEC-131K Owner's Manual Aircraft Receiver Kit

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

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

Installation

Key

1 2 3 4

Pin Numbers

Metal Tab

PARTS LIST

Your kit should contain all of the parts listed below. Please identify and inventory each item on the checklist before you start building. If any parts are missing or damaged, refer to the manual's warranty section for replacement instructions. If you can't positively identify an unfamiliar item on the basis of the information given, set it aside until all other items are checked off. You may

VEC-131K Owner's Manual Aircraft Receiver Kit

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.

Capacitors:

Qty Part Description Designation

1 2.2 pF ceramic disc (marked 2.2) C4

1 4.7 pF ceramic disc (marked 4.7) C2

1 6.8 pF ceramic disc (marked 6.8) C6

1 10 pF multilayer (marked 100 or 10) C1

2 18 pF multilayer (marked 180 or 18) C11,C12

2 33 pF multilayer (marked 330 or 33) C3,C5

2 100 pF multilayer (marked 101) C7,C14

1 220 pF ceramic disc (marked 221) C24

1 1000 pF multilayer (marked 102) C13

3 .001 uF ceramic disc (marked 102) C8,C15,C17

7 .01 uF ceramic disc (marked 103) C9,C16,C19,C20,C21,C27,C29

5 .1 uF ceramic disc (marked 104) C10,C22,C30,C32,C35

1 1 uF electrolytic (marked 1 uF) C23

3 10 uF electrolytic (marked 10 uF) C25,C26,C28

1 47 uF electrolytic (marked 47 uF) C18

2 100 uF electrolytic (marked 100 uF) C31,C33

1 470 uF electrolytic (marked 470 uF) C34

VEC-131K Owner's Manual Aircraft Receiver Kit

Fixed Resistors:

Qty Part Description Designation

1 22 ohm (red-red-black-gold) R23

1 100 ohm (brown-black-brown-gold) R11

3 470 ohm (yellow-violet-brown-gold) R2,R3,R8

3 1K ohm (brown-black-red-gold) R9,R13,R21

3 2.2K ohm (red-red-red-gold) R7,R12,R19

3 10K ohm (brown-black-orange-gold) R15,R17,R22

3 47K ohm (yellow-violet-orange-gold) R5,R14,R16

3 100K ohm (brown-black-yellow-gold) R1,R4,R10

1 1M ohm (brown-black-green-gold) R20

Variable Resistors:

Qty Part Description Designation

2 10K ohm potentiometer R6,R18

Diodes:

Qty Part Description Designation

1 1N270 Germanium diode D3

1 1N5235B 6.8Vdc Zener diode D2

1 MV2104 varicap tuning diode D1

Integrated Circuits:

Qty Part Description Designation

1 LM358N dual op-amp, AGC amplifier U3

1 LM386N audio amplifier U4

1 MC1350P IF amplifier U2

1 NE602 or SA602 RF mixer U1

Transistors:

Qty Part Description Designation

1 2N3904 NPN IF amplifier Q2

1 2SC2498 NPN, VHF LNA Q1

Filters:

Qty Part Description Designation

1 10.7-MHz ceramic IF filter (SFE10.7) FL1

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