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VEC-121K Owner's Manual 

Crystal Radio Set Kit 

INTRODUCTION 

Relive those bygone days of radio--a time almost 90 years ago, when early radio 
pioneers experimented with crystal radio receivers!  Wind your own “inductor” 
coil, wire up the earliest radio circuit; and, there’s no soldering needed!  
Everything is assembled on a pine “breadboard”, just like great, great granddad 
did when he was a youngster.  Learn about basic radio theory.  Put up an antenna 
(wire included), connect a ground, and experience the magic of a radio that 
needs no power.  A special high-sensitivity earphone allows you to hear AM 
Broadcast signals from many miles away; this little baby really performs.  The 
VEC-121K is a fascinating project for youngsters of all ages! 

The VEC-121K features a modern “fixed detector”, eliminating the need for 
frequent and frustrating catwhisker adjustments.  A large, Hi-Q antenna coil, and 
a modern miniature Hi-Q tuning capacitor, are used for best sensitivity and 
selectivity.  The high-impedance parallel-resonant tuning circuit allows a short 
receiving antenna to deliver maximum signal to the set. 

 

TOOLS AND SUPPLIES 

Having the right tool to do a job always makes things go better.  There is no 
soldering required, and only a few basic hand tools are needed to assemble your 
VEC-121K crystal radio set. 

This is a list of the tools you will need: 

SAFETY EYEGLASSES or GOGGLES!  

Working with wires, tools and radio 

parts is a lot of fun, but please, 

safety first

!  Your local hardware store carries 

inexpensive safety goggles.  Before you are going to be cutting or working with 
wires, hammering, handling any chemicals, or using any tools,  put on your 
safety eye wear first!

 

1. 

Phillips screwdriver.

   There are eight Phillips head screws included in the 

kit, and we will use this tool when it is time to mount parts on the wood 
board.  Try to find a screwdriver with a 

shaft 

(the distance between the tip 

and start of the handle) that is at least 3” long. 

2. 

Long-nose pliers.

   These pliers have a long and tapered nose and are used 

by electricians.  The long slender nose makes it easy to hold or bend a wire 
that is being worked on.

 

3. 

Wire cutters.

   These special pliers have sharp cutters to cut wires.  Some 

long-nose pliers styles feature built-in wire cutters.  Wire cutters are 
sometimes called “nippy cutters” or “diagonal wire cutters”—depending on 
how they’re made. 

Содержание VEC-121K

Страница 1: ...ific 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 cha...

Страница 2: ...it 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...

Страница 3: ...ximum signal to the set TOOLS AND SUPPLIES Having the right tool to do a job always makes things go better There is no soldering required and only a few basic hand tools are needed to assemble your VE...

Страница 4: ...o assemble plastic model airplanes are safer to work with and may also be used instead of super glue However they will require a longer time to dry Always have an adult advise and supervise your use o...

Страница 5: ...few days This will allow the stain to fully cure or dry so it does not interfere with the tape adhesive BEFORE YOU START BUILDING Your work area Use a good workbench with good lighting so you can see...

Страница 6: ...a SlinkyTM toy Doing so will cause the wire to twist and make kinks when you try to use it Instead hold the spool of wire in both hands and carefully unroll the wire from the spool Re tape the unused...

Страница 7: ...the Fahnstock clips mounted on the pine board Note we show the wire as a dotted line where it passes under the Fahnstock clip When the Phillips screw is tightened a good electrical connection is made...

Страница 8: ...t 6 The wire insulation is removed where shown in the directions and made into a half loop as shown above The above drawing shows a through connection being made to a Fahnstock clip The dotted line sh...

Страница 9: ...the Vectronics kit warranty section of the manual Qty Part Description 8 Phillips head screws 1 5 inch length of white 2 1 2 diameter PVC plastic pipe 1 100 foot spool of 18 AWG enamel coated wire 6...

Страница 10: ...VEC 121K Owner s Manual Crystal Radio Set Kit 8 Resistor Germanium diode 1N34A STEP BY STEP CONSTRUCTION...

Страница 11: ...small hammer make a small punch mark at each of the eight screw hole locations These marks will show you where the screw holes are located on the board Don t drive the nail into wood We need only make...

Страница 12: ...holes align properly with the breadboard s mounting holes you may remove the coil and return the screws to the parts bag If things don t match up just right you will have to mark the correct position...

Страница 13: ...If the copper wire kinks during handling smooth it out as best you can before trying to wind it We are going to wind a single layer coil this is called a solenoid winding The winding is done in sever...

Страница 14: ...tight even and spaced together After several turns are completed examine your work Keep your thumb in place so the wire doesn t loosen on the coil form The wire windings should be even and spaced so t...

Страница 15: ...s you have just completed Are they tightly wound and free of gaps between adjacent windings Squeeze the newer windings towards the starting windings to close up any gaps When you re satisfied use mask...

Страница 16: ...six Fahnstock clips and six of the eight Phillips screws supplied with the kit Refer to the positioning guide below for the following steps GND ANT EAR2 DET1 DET2 EAR1 In the following several steps...

Страница 17: ...the remaining two Phillips head screws Mount the coil to the board using the two Phillips head mounting screws Before tightening the screws make sure the two 16 coil lead wires are oriented towards th...

Страница 18: ...clip Route the through connection loop so it passes between the ANT Fahnstock clip and breadboard Tighten the ANT clip mounting screw so it is snug Measure and mark the wire lead emerging from the ant...

Страница 19: ...ntil snug Measure the wire exiting from the EAR2 connection and at the 5 5 point remove 1 of insulation from the wire Form the area of wire stripped of insulation into a second through connection half...

Страница 20: ...in the kit Remove 1 of insulation from each end Form each end of the wire into an end connection Loosen the screws mounting the Fahnstock clips DET2 and EAR1 Take one of the wire end connections and...

Страница 21: ...en the two Phillips screws for EAR1 and EAR2 clips Put one of the half loop connections between the top of the clip body and the bottom of the screw head for the EAR1 clip Adjust the size of the loop...

Страница 22: ...ery small diameter and may not be held tightly enough by the clip unless the leads are made a bit thicker Follow the diagram below and clip the diode s anode lead into the DET1 Fahnstock clip and the...

Страница 23: ...es As the shaft is turned the plates are either meshed or unmeshed changing the capacitance value This is how the tuning capacitor works The tuning capacitor will be mounted at the front center of the...

Страница 24: ...y opening in the plastic capacitor housing Take the wire from the GND clip and insert it into this capacitor opening Carefully feed the wire so it passes through the capacitor body it will be between...

Страница 25: ...to a length of 4 Remove 1 of insulation from the wire end Wind the wire over the stud to form three tightly wound turns See the following drawing Use enough wire so when finished you have a small pig...

Страница 26: ...citor body outline by tracing its outline onto the breadboard with a pencil Find the double sided foam tape Remove one of the protective covers from one side of the tape Place the sticky side over the...

Страница 27: ...uning knob on the shaft extension This completes the construction of the VEC 121K crystal set receiver TESTING AND ALIGNMENT 1 Turn the capacitor shaft in a counter clockwise direction until the stop...

Страница 28: ...ceive signals If you live in a salt marsh or along the shore you may experience exceptional reception The fellow living in an arid area with poor soil moisture may have much poorer reception When to l...

Страница 29: ...is being used The most effective ground is a 10 foot ground rod driven into the earth If you have a TV antenna on your home it should be connected to a ground rod for lightning protection If it is ne...

Страница 30: ...s to the tuning capacitor were used Signals are very weak or I can only hear one station Again this may be normal if there are no strong signals in your area Check your ground and antenna connections...

Страница 31: ......

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