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SC-1 

 4 

INTRODUCTION 

 

 
The Ramsey SC1 Shortwave Converter is perhaps one of the most 
enjoyable, versatile and interesting radio kits you could ever build. And, since 
it is exceptionally easy to build and use, it is a great kit for beginners. 
Ramsey Electronics designed the SC1 especially for use with car radios. Its 
flexible and practical features make it ideal for this kind of use and the 
manual will explain why this is so. The other "ideal" receiver with which to 
use the SC1 is a good quality AM-FM home stereo system. In fact, an SC1 
converter has put fresh life into the stereo system in my own office. Even 
though I've enjoyed a variety of shortwave and Ham receivers over the years, 
there's nothing quite like smoothly tuning the BBC, Radio Moscow, VOA or 
Paris on a quality stereo tuner and hearing it all as a big sound through high-
power speakers! And you’ll have so much control over sound quality with 
bass, treble, equalizing, etc.   
 
QUESTION: What exactly is a "shortwave converter"?    
ANSWER: Any receiver converter is a device which "force feeds" signals 
from another frequency band into the antenna input line of a normally 
complete, functioning receiver. Virtually any receiver can be converted to 
receive other bands in this manner. The receiver functions as a tuneable "IF" 
and its good circuit qualities carry over to the newly received frequency band 
of interest. If a radio is considered to be a double conversion superhet, the 
addition of a converter makes it a triple conversion superhet. Both car radios 
and quality home stereos are ideal for shortwave conversion because of 
their:      
 

excellent sensitivity    

sophisticated superhet, hi-fi receiver circuitry  

smooth, accurate dial tuning  

design for use with an external antenna   

 
A car radio is designed to endure many bumps and engine noise. A home 
stereo receiver or tuner is designed for maximum sound quality in AM-band 
reception. Both are designed to be the best AM receiver circuits possible. 
And since both rely on an external antenna, both are ready to use the SC1 
Shortwave Converter!    
 
A receiver designed for an external antenna is preferred for converter 
operation over the typical portable or table radio with built-in antenna, since 
you don't have to do anything within the radio itself for best shortwave band 
performance. The SC1 may be used with a portable or table AM-band radio, 
but you can expect a need for some internal connections to make sure that 
the SC1 output "gets ahead" of the radio's built-in antenna. In these days 

Summary of Contents for SC1

Page 1: ...h any AM radio car radios are ideal Tune from your regular radio dial easily set station presets etc on your existing radio Operates on 9 to 15 volts Listen to worldwide broadcasts in your car boat or...

Page 2: ...er Direction Finder HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer CPO3 Code Practice Oscillator QRP Power Amplifiers RAMSEY MINI KITS Many other kits are available for hob...

Page 3: ...to the SC1 4 What you can expect to hear 5 Parts list 6 SC1 Parts layout 7 SC1 Circuit description 8 SC1 Assembly instructions 9 Setting up the SC1 12 Setting your listening bands 13 Understanding wha...

Page 4: ...g receiver Virtually any receiver can be converted to receive other bands in this manner The receiver functions as a tuneable IF and its good circuit qualities carry over to the newly received frequen...

Page 5: ...dulation You will also hear a variety of other interesting sounds but just remember that this receiving set up is designed for listening to AM style broadcast formats Morse code CW or teletype signals...

Page 6: ...marked 42IF123 L1 1 Shielded coil marked 42EB L2 3 3 9 uH inductor green body with a large silver band followed by orange gold white silver bands L3 L4 L5 RESISTORS 2 470 ohms yellow violet brown R4...

Page 7: ...SC 1 7 RAMSEY SC1 PARTS LAYOUT...

Page 8: ...nge of the AM radio For example to receive 10 MHz WWV the radio dial is set to 1000 KHz and the SC 1 oscillator is set to 9 MHz Another way of viewing it is that if the oscillator is set to 9 MHz the...

Page 9: ...the schematic circuit diagram from time to time Enough talk let s get building 1 Install J3 the DC power jack 2 Install J1 the antenna or RF input jack 3 Install S1 the first of two DPDT push style sw...

Page 10: ...20 Install transistor Q1 2N3904 Observe correct position of the flat side 21 Install C13 4 7 or 10 uF the ONLY electrolytic or polarized capacitor in the SC1 kit Electrolytic capacitors have a right...

Page 11: ...ion before installation There is a small tubular capacitor visible in the plastic bottom of the coil that needs to be removed which is done by crushing it with the tip of a small screwdriver or the po...

Page 12: ...and hard wiring into the car s fuse block Some automobile ignition systems cause noise which needs to be suppressed for satisfactory operation of ANY radio device When using this converter in a car y...

Page 13: ...n how to set up L1 and L2 for your choice of two 1 MHz SW bands selected by S2 tuned by the AM radio If you aren t familiar with shortwave broadcast band frequency allocations but have and know how to...

Page 14: ...dio TV Feed Service Master programming source for the U S military radio hear CBS NBC ABC Mutual news on all the same channel plus many other features and spots which give a feel for how it s going wi...

Page 15: ...IO HAMS AND EXPERIMENTERS The SC1 Shortwave Converter can be a fun platform for putting an extra AM radio set to work for listening to your favorite band Brand new AM only car radios pulled from new v...

Page 16: ...s that includes a nifty Stereo FM Transmitter You can transmit your favorite music or radio calls throughout the house and yard with this low cost kit Another handy kit is our Speakerphone kit that al...

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Page 19: ...tty much be assured that the 1K ohm resistors are actually the missing 10 K parts Hum m m I guess the red band really does look orange Ramsey Electronics project kits are packed with pride in the USA...

Page 20: ...Ramsey Publication No SC1 Assembly and Instruction manual for RAMSEY MODEL NO SC1 SHORTWAVE CONVERTER KIT REQUIRED TOOLS Soldering Iron Ramsey WLC100 Thin Rosin Core Solder Ramsey RTS12 Needle Nose Pl...

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