SHORTWAVE CONVERTER KIT Ramsey Electronics Model No. SC1 Fascinating listening for all ages and abilities - tunes the world from any standard AM broadcast receiver. Put some ‘spark’ into that commute to work or that long trip, listen to shortwave in your car! • Switch selectable for any two shortwave bands from 3 to 18 MHz - you pick the bands! • Works with any AM radio - car radios are ideal! • Tune from your regular radio dial - easily set station presets, etc. on your existing radio.
RAMSEY TRANSMITTER KITS • FM100B Professional FM Stereo Transmitter • FM25B Synthesized Stereo Transmitter • AM1, AM25 AM Transmitters • TV6 Television Transmitter RAMSEY RECEIVER KITS • FR1 FM Broadcast Receiver • AR1 Aircraft Band Receiver • SR2 Shortwave Receiver • AA7 Active Antenna • SC1 Shortwave Converter RAMSEY HOBBY KITS • SG7 Personal Speed Radar • SS70A Speech Scrambler • SP1 Speakerphone • WCT20 Wizard Cable Tracer • PH10 Peak hold Meter • LC1 Inductance-Capacitance Meter RAMSEY AMATEUR RADIO KI
Ramsey Publication No. SC1 Price $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR SHORTWAVE CONVERTER KIT TABLE OF CONTENTS Introduction 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 ..................................
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.
when portable broadcast band radios are very cheap, or often available free in various promotions, we can only suggest that you study how a particular radio is designed and that you figure out how to get the RF output of the SC1 beyond the internal ferrite rod antenna of the AM radio. To get the most from your SC1, we suggest that you plan to use it with a good quality AM radio with an external antenna connection.
PARTS SUPPLIED WITH THE SC1 KIT CAPACITORS 1 4.7 or 5 pF disc [marked 4.7 or 5K] (C6) 2 100 pF disc [marked 100, 101, or 101K] (C7,C8) 2 470 pF disc [marked 470 or 471] (C2,C3) 5 .001 uF disc [marked .001, 102, or 1 nF] (C1,C4,C5,C9,C10) 2 .01 uF disc [marked .01, 103, or 10 nF] (C11,C12) 1 4.7 or 10 uF electrolytic (C13) INDUCTORS 1 Shielded coil marked 42IF123 (L1) 1 Shielded coil marked 42EB (L2) 3 3.
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CIRCUIT DESCRIPTION Q3 functions as part of a variable Colpitts oscillator which utilizes S2 and jumper points A,B,C to setup a choice of preferred local oscillator frequencies from 3 to 22 MHz. L2 and C10 may be replaced by a crystal for tuning in a desired range 500 to 1600 KHz around the crystal oscillator frequency. C2,C3 and L3,L4 and L5 form a high-pass filter from the antenna to pass shortwave signals only and to minimize strong local AM broadcast signals.
RAMSEY SC1 KIT ASSEMBLY In all PC board assembly steps, our word "INSTALL" means to do this: • Insert the part, oriented or "pointed" correctly, into its holes in the PC board. • If helpful, gently bend the part's wire leads or tabs to hold it in place, with the body of the part snugly against the top side ("component side") of the circuit board. • Solder ALL wires or pins of the part.
❒ 13. Be certain to double check your component values, this will save you a lot of problems! Now let's get back to building! ❒ 14. Install R2, 1K [brown-black-red]. ❒ 15. Install R6, 470 ohms [yellow-violet-brown]. ❒ 16. Install C12, .01 uF (marked .01 or 103 or 10 nF). ❒ 17. Install R5, 1K ohm [brown-black-red]. ❒ 18. Install C5, .001 uF (marked .001, 102, or 1 nF). C5 couples Q2 to the PC board trace leading to the receiver jack. ❒ 19. Install J2, the output jack to the AM receiver.
❒ 31. Install C9, .001 uF (marked .001, 102, or 1 nF). Installation of Q3 oscillator coils L1 and L2: The wiring of your SC1 is now finished except for your own plans about how to use and tune it. If you expect to exercise options other than our suggestions for basic shortwave broadcast listening, read the information following the assembly directions before proceeding. Otherwise, complete the following steps. ❒ 32. Install L2, marked 42EB. Do not confuse it with the other shielded coil.
SETTING UP THE SC1 FOR A HOME STEREO SYSTEM: ❒ 1. Make sure the stereo AM-FM receiver has provisions for attaching an external AM antenna. Sometimes, the built-in antenna wires are detachable from the rear-panel antenna terminals. ❒ 2. Prepare a short coaxial cable with suitable connectors or wire ends to make a neat connection between the SC1 and the receiver AM antenna terminals. ❒ 3. Provide a 9 to 12 volt battery power supply.
SETTING YOUR LISTENING BANDS The nice thing about the SC1 for beginners is that you'll hear some kind of shortwave signals as soon as you hook it up to your AM radio and a suitable antenna. As long as you wired it up right, your AM radio has no choice but to tune shortwave! You can enjoy the SC1 without even knowing what frequency you are hearing.
Notice that the 11MHz band is available in BOTH the B-C and A-C jumper settings for L1. The higher frequency bands are intended primarily for daytime broadcasting. Reception quality is very dependent upon atmospheric propagation conditions. Even though there is quite a sport and science to digging up exotic broadcasts from hundreds of countries in any of the above bands, newcomers will find more immediate satisfaction from setting up L1 for the 9 MHz (31 Meter) band, and L2 for 5.9 to 6.2 MHz.
UNDERSTANDING WHAT YOUR RADIO IS ACTUALLY TUNING As mentioned in the SC1 circuit description, this converter is broadbanded, meaning that there is no provision to pre-tune the antenna input to a particular frequency band. This design poses little problem for casual shortwave broadcast listening, but it would not be the right design for a communications receiver relied upon for tuning weak, distant signals.
If you've enjoyed building this kit, why not consider some other fine Ramsey kits? There are other bands to explore and Ramsey has them covered or, how about building your own VHF FM Transceiver? The FX series transceivers from Ramsey are packed with features that allow you to get on FM for less than the cost of someone else's second-hand flea market rig. All ages, from 10 to 83, have built and are enjoying operating a rig they built themselves.
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The Ramsey Kit Warranty Please read carefully BEFORE calling or writing in about your kit. Most problems can be solved without contacting the factory. Notice that this is not a "fine print" warranty. We want you to understand your rights and ours too! All Ramsey kits will work if assembled properly. The very fact that your kit includes this new manual is your assurance that a team of knowledgeable people have field-tested several "copies" of this kit straight from the Ramsey Inventory.
Shortwave Converter Kit Quick Reference Page Guide Introduction 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 Adjusting your listening bands ................13 Understanding what you're tuning ...........15 Schematic diagram ........................
