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Ramsey Electronics Model No.              SCA1 

 

Tunes entire SCA subcarrier band 50 - 100 KHz 

 

Excellent performance - uses PLL decoder 

 

Feature both speaker and line-level audio outputs    

 

Connects to any FM receiver or simply plugs into our 

                  

FR-1 FM broadcast receiver  

 

Band-pass filtered input for excellent fidelity 

 

Front panel volume and tuning controls 

 

Informative manual answers questions on 

                  

theory, hook-ups, and uses - enhances resale  

                  

value , too!

 

 

Add our case set for a finished ‘Pro’ 

                  

look. Cases match all Ramsey products 

 

Clear, concise assembly instructions carefully guide you 

                  

to a finished kit that works the FIRST time!

 

 

 

SCA FM SUBCARRIER 
DECODER KIT 

Commercial-free music, stock quotes, news - all available 
around-the-clock on your local FM station? Sure, buried in a  
special subcarrier that you’ll be able to tune with the SCA-1. 
This is how most restaurants, department stores, and hotels 
pick up their music. 

 

Summary of Contents for SCA1

Page 1: ...tive manual answers questions on theory hook ups and uses enhances resale value too Add our case set for a finished Pro look Cases match all Ramsey products Clear concise assembly instructions careful...

Page 2: ...ppler 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...

Page 3: ...er background 4 Circuit description 6 Parts list 7 Parts layout diagram 9 Schematic diagram 10 Assembly instructions 11 Set up and testing 15 Hook up details 16 Troubleshooting guide 17 Enclosure idea...

Page 4: ...FM broadcast band receiver with SCA baseband demodulator output model FR 1 which allows an easy one step hookup for the adapter Due to the myriad of different receivers and possible combinations that...

Page 5: ...ignal contains a Left Right FM modulated carrier which is the standard monaural audio signal and a Left Right signal which is used to provide the stereo signal Follow closely to see how we get separat...

Page 6: ...less than 19 KHz If it wasn t while sitting back enjoying your Hi Fi you d be able to smell your tweeters burning up as they tried to reproduce the constant 19KHz pilot signal In addition to all this...

Page 7: ...DIP 2 2N3904 NPN transistors OTHER COMPONENTS 1 SCA1 Printed circuit board 1 DPDT push button switch S1 2 10K ohm PC mount potentiometer R1 12 2 PC mount RCA jack J1 2 1 PC mount subminiature speaker...

Page 8: ...SCA1 8 SCA SUBCARRIER DEMODULATOR PARTS LAYOUT DIAGRAM...

Page 9: ...SCA1 9...

Page 10: ...undesired locations 5 Solder all connections unless directed otherwise Use enough heat and solder flow for clean shiny completed connections Don t be afraid of any pen style soldering iron having enou...

Page 11: ...that the control is pressed in firmly and straight against the top of the board Solder the three center pins and then the two larger mechanical mounting tabs Use enough solder for a solid robust conn...

Page 12: ...is less than perfect BUILDING THE VOLTAGE CONTROLLED OSCILLATOR 17 Install R3 2 2K ohm red red red 18 Install C2 10uf electrolytic capacitor Electrolytic capacitors are polarized and must be installed...

Page 13: ...e frequency as the input If the input frequency changes as when it is frequency modulated the VCO will track and follow it exactly In this way the control voltage provides an exact replica of the modu...

Page 14: ...gain will be significantly increased This can however be too much of a good thing and cause feedback or audio distortion depending on the speaker used It s recommended that you do not install the com...

Page 15: ...ou should hear a hiss similar to the interstation noise heard on a standard FM radio As the audio oscillator is tuned to the frequency that the SCA1 is tuned to you should hear a quieting in the speak...

Page 16: ...d to the receiver s ground The other end of this coax is connected to the SCA1 s input jack J1 If your radio is plugged into the AC line be sure to use caution when poking around And be sure your SCA1...

Page 17: ...broadcast receiver is the only combination that we here at the factory have any familiarity with Here are a few common problems along with solutions which may help in simple troubleshooting PROBLEM O...

Page 18: ...y or construction error Have another pair of eyes check your work first ENCLOSURE IDEAS While we believe that the Ramsey enclosure and knob option is a fine value for finishing off your Ramsey receive...

Page 19: ...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 If you b...

Page 20: ...sembly and Instruction manual for RAMSEY MODEL NO SCA1 SCA DECODER KIT This Quality Electronics Kit was designed and packed in the USA REQUIRED TOOLS Soldering Iron Ramsey WLC100 Thin Rosin Core Solde...

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