4-10 MHz SHORTWAVE RADIO Ramsey Electronics Model No. SR-1 Have you ever wanted to get into the fascinating world of radio? The Ramsey SR-1 is a fine performer that will bring in the world using just a few feet of wire as an antenna! Folks of all ages have successfully built and enjoyed this easy and fun kit. • Enjoy hours of fascinating international listening using just a simple indoor wire antenna • Select any 2.5MHz portion of the 4 to 10MHz shortwave band, easily re-tuned at any time.
PARTIAL LIST OF AVAILABLE KITS RAMSEY TRANSMITTER KITS • FM-10 FM Stereo Transmitter • FM-25 Synthesized FM Stereo Transmitter • AM-25 Synthesized AM Transmitter • AM-1 AM Transmitter ld st ki or RAMS LECTR Be RAMSEY HOBBY KITS • SG-7 Personal Speed Radar • SS-70 Speech Scrambler • TT-1 Telephone Recorder • SP-1 Speakerphone • MD-3 Microwave Motion Detector • PH-10 Peak hold Meter • LC-1 Inductance-Capacitance Meter E Y E I CS ON RAMSEY RECEIVER KITS • FR-1 FM Broadcast Receiver • AR-1 Aircraft B
Ramsey Publication No. MSR-1 Manual Price Only: $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR 4-10MHz SHORTWAVE RADIO TABLE OF CONTENTS Introduction to the SR-1....................................... 4 What You Can Expect to Hear............................. 4 Shortwave Listening as a Hobby ......................... 5 Circuit Description ............................................... 6 Parts Layout Diagram .......................................... 7 Parts List ...........................................
INTRODUCTION TO THE SR-1 The SR-1 is a single-conversion superheterodyne receiver designed specifically for listening to AM broadcasting stations in the range of 4 to 10 Mhz. Because of this "superhet" design, your favorite foreign broadcasting services will come in loud and clear, with pleasing audio sound quality, with a minimum of overload, frequency drift or heterodyne whistles.
• Radio Canada International: editorial quality similar to BBC • Radio Moscow: powerful signals, increasingly honest and open • Voice of America: VOA broadcasts are "aimed" outside the USA, but if you're in the "path" you'll hear it loud and clear! • U.S. Armed Forces Radio-TV "Feed" Service: master programming source for U.S. military radio- hear CBS-NBC-ABC-Mutual news all on the same "channel," plus many other features and spots which give a feel for how it's going with those in uniform.
at least $100 for a receiver offering a significant improvement over your trusty SR-1. To learn more about this SWL hobby, look for a copy of "Popular Communications" at newsstands. An inexpensive and interesting general introduction to all kinds of radio listening is the book, "Shortwave Listening Guide" by William Barded, Jr. (1987; Radio Shack Catalog Number 621084).
SR-1 PARTS LAYOUT DIAGRAM SR-1 – 7
PARTS LIST CAPACITORS 3 100 pf disc capacitors (marked 100, 101, or 100K) (C3,7,8) 11 .01µF disc capacitors (marked .01, 103, or 10nF) (C1,2,5,9,10,11,12,13,14,15,18) 3 4.7µF to 10µF electrolytic capacitors (C6,17,22) 3 100 to 220µF electrolytic capacitors (C16,20,21) 1 .1µF ceramic disc capacitor (marked .
ASSEMBLY INSTRUCTIONS 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.
shielded transformers can be installed, their internal capacitors need to be removed. Looking at the underside of these two transformers, you'll see a tubular part, probably white with a brown band, somewhat like the resistors in this kit. These are brittle and easily crushed with any sharp object that can be pressed against them with mild force(small nail, nutpick, small screwdriver). You'll find these capacitors will easily disintegrate into particles.
range. 17. Install L2, the oscillator coil. 18. Install D1, the varactor diode, which looks just like a transistor but with only two leads, making sure that the flat side is oriented correctly. 19. Install R5, 270 ohm (red-purple-brown) 20. Install R2, 10K potentiometer tuning control. 21. Install C6, 10 µF. electrolytic below R2. 22. Install R3, 10K potentiometer volume control. 23. Install C9, .01 µF (marked .01, 103 or 10nF).
26. Install C15, .01 µF (marked .01, 103 or 10nF). 27. Install C7 and C8, both 100 pF (marked 100, 101 or 100K). 28. All four transistors used in the SR-1 are identical NPN type 2N3904 or similar. Transistors are installed just like any other part - don't be afraid to use enough heat to make good, clean connections. When installing transistors, gently work their three leads to slide into the three holes at the same time, don't try to pre-form the wires. Press firmly without jamming too hard. 29.
50. Install R16, 2 ohm [red-black-gold]. PROGRESS SUMMARY Your shortwave broadcast receiver is now finished, except for using just a few more parts to build a very effective speaker amplifier circuit. 51. Near R3 (volume control), install C17, 10 µF. electrolytic. This and most remaining capacitors are polarized electrolytics, so please watch your (+) and (-) designations and part orientations! 52. Install C18, .01 µF (marked .01, 103 or 10nF). 53. Install U3, the LM386 audio amplifier IC chip.
sensitive, so its antenna requirements are minimal for casual evening listening when international broadcast signals are quite strong. 10 to 20 feet of insulated hookup wire can be neatly strung behind furniture and curtains for an adequate indoor antenna. The same length of wire, or more, outdoors or up in the attic, will be an even better receiving antenna. • 1.
INITIAL TESTING AND ADJUSTMENT Before turning on your receiver, please double-check the following: correct orientation of all three IC's. correct orientation of flat side of all four transistors. correct orientation of the two diodes. correct polarity of all electrolytic capacitors. 1. Connect a speaker or earphones and antenna. 2. Install a fresh 9-volt alkaline battery. 3. Set all three potentiometer controls to their middle positions. 4. Turn ON the receiver.
If you like precision, use a frequency counter or calibrated receiver to find the SR-1's strong oscillator signal, remembering that there is a 260 Khz IF difference between the local oscillator frequency and the broadcast signal you are hearing. Following are results of tests on an SR-1 to give you a general guideline on what to expect if you want to pre-set adjustments of oscillator coil L2. Each turn of L2 is one full turn clockwise.
TROUBLESHOOTING TIPS If you experience difficulty, think of your SR-1 in its several sections or stages: oscillator-mixer (NE602), IF audio and AGC, and final audio output (LM386). The first step in case of problems is to make sure that the tunable oscillator is working, which can be done by listening for its signal on another receiver.
battery will give very satisfactory service. THE RAMSEY ELECTRONICS CASE, KNOB & HARDWARE OPTION Your finished receiver can be installed in a variety of enclosures of your own design and choosing. You might be planning to combine several Ramsey circuit kit boards in a single enclosure. Use of the inexpensive and attractive Ramsey case and knob kit will give your unit that finished look and increase its resale value.
A TUNING DIAL? If you use your own enclosure and knobs, you will probably plan some sort of dial markings.
Notes: SR-1 – 20
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.
SR-1 Shortwave Receiver Quick Reference Page Guide Introduction to the SR-1 ...................... 4 What You Can Expect to Hear ............ 4 Shortwave Listening as a Hobby......... 5 Circuit Description ............................... 6 Parts Layout Diagram ......................... 7 Parts List ............................................. 8 Assembly Instructions ......................... 9 Schematic Diagram............................. 12 Shortwave Antenna Ideas ...................
