Ramsey_SR-1_user.pdf
SR-1 1 Ramsey Electronics Model No. SR-1 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. Smooth varactor diode tuning Excellent sensitivity and selectivity Front panel RF Gain, Volume, and Tuning controls Multi-stage audio amplifier for room filling volume Well designed superhetrodyne circuit is easy to build, makes a nice one-evening project Ideal scout, school, or club project Clear, concise step-by-step instructions carefully guide you to a finished kit that not only works - but youll also learn too! Runs on a standard 9 volt battery Add our matching case and knob set for a finished pro look. Check out the excellent magazine reviews in: August 1989, 73: Amateur Radio Today September 1990, Popular Electronics November 1991, Radio Fun 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. 4-10 MHz SHORTWAVE RADIO SR-1 2 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 RAMSEY RECEIVER KITS FR-1 FM Broadcast Receiver AR-1 Aircraft Band Receiver SR-1 Shortwave Receiver AA-7 Active Antenna SC-1 Shortwave Converter 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 RAMSEY AMATEUR RADIO KITS FX Series VHF and UHF Transceivers HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW-7 CW Keyer PA Series VHF and UHF Power Amplifiers Packet Computer Interfaces QRP Power Amplifiers RAMSEY MINI-KITS Many other kits are available for hobby, school, scouts and just plain FUN. New kits are always under development. Write or call for our free Ramsey catalog. 4-10MHz SHORTWAVE RADIO INSTRUCTION MANUAL Ramsey Electronics publication No. MSR-1 Revision E1 First printing: October, 1994 COPYRIGHT 1994 by Ramsey Electronics, Inc. 793 Canning Parkway, Victor, New York 14564. All rights reserved. No portion of this publication may be copied or duplicated without the written permission of Ramsey Electronics, Inc. Printed in the United States of America. R A M S E Y E L E C T R O N I C S B e s t k i t b u i l d e r s i n t h e w o r l d SR-1 3 4-10MHz SHORTWAVE RADIO Ramsey Publication No. MSR-1 Manual Price Only: $5.00 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 . 8 Assembly Instructions . 9 Schematic Diagram . 12 Shortwave Antenna Ideas . 15 Initial Testing and Adjustment . 17 Troubleshooting Tips . 19 Case, Knob and Dial Information . 20 Ramsey Kit Warranty . 23 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR RAMSEY ELECTRONICS, INC. 793 Canning Parkway Victor, New York 14564 Phone (716) 924-4560 SR-1 4 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. Because of this broadcast oriented design, other shortwave signals such as Morse code (CW), single- sideband (SSB) voice communications and some Teletype signals will usually sound like garbled hisses. On the other hand, similarly inexpensive receivers designed for CW and SSB can give only marginal performance in receiving broadcast stations due to the lack of superheterodyne design. For example, our popular Ramsey direct-conversion receivers for the 80,40,30 and 20 Meter Amateur bands will also pick up AM broadcast stations, but youll mainly hear their strong AM carrier signal due to the lack of the superheterodyne circuitry. Even if such a carrier is tuned to a null, listening fidelity is less than desirable. WHAT YOU CAN EXPECT TO HEAR First, lets take a look at what is POSSIBLE to hear on your SR-1. The following are the international shortwave broadcasting bands within its tuning range: 4.750-5.060 Mhz. (Lower power, regional tropical broadcasting) 5.950-6.200 Mhz (Late evening) 7.100-7.300 Mhz. (Late afternoon, early evening) (This band is always shared with the 7.0-7.3 Mhz Amateur Radio Band) 9.500-9.900 Mhz. (Always something on, 24 hours a day!) Especially strong signals include these, among others: BBC London: an intelligent perspective on world affairs SR-1 5 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 youre in the path youll 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 its going with those in uniform. Numerous South American stations USA religious broadcasting to other continents Youll easily tune in broadcasts from many other countries as well. As you become more and more familiar with the world of shortwave broadcasting, youll be deciding on your own favorite band. You will hear a variety of other interesting sounds, but just remember that this receiver is designed for AM only. If a Morse Code signal really sounds good, it is because it is being transmitted in AM tone-modulated form, or perhaps the signal is so close to an AM broadcast carrier that the carrier acts as a beat-frequency-oscillator (BFO). Even though this receiver can let you tune through several different ham radio bands, the signals are not likely to be intelligible. Reception of CW and SSB signals on an AM receiver requires a BFO. This is not a complicated feature, but it is beyond the purpose of the SR-1. Our companion receivers designed for the HAM bands will let you tune into these SSB and CW broadcasts. SHORTWAVE LISTENING AS A HOBBY IN ITSELF Many people worldwide enjoy listening to shortwave broadcasts of all kinds, and they keep written records of what they hear. Almost every nation on earth has some sort of shortwave broadcast service, though many are much more challenging to tune than the powerful signals of Radio Moscow and the BBC. In addition, these SWLs (Shortwave Listeners) listen to ham operators, government and commercial stations and even clandestine operations. Some shortwave listeners enjoy collecting QSL cards from stations which they have logged. Shortwave listening is, for some, a step toward getting a ham radio license. For others, it is a great hobby in itself. The SR-1 Shortwave Receiver is a good introductory receiver for this hobby. After you decide exactly what kinds of listening are of the most interest to you, youll be a better position to choose a more elaborate receiver. While there are various multi-band portable radios available, you can expect to pay SR-1 6 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 62- 1084). This book also includes helpful introductory information about VHF monitoring, which you can enjoy with the Ramsey FR-146 and AR-1 receiver kits, as well as ham radio, CB, antennas, and other topics. To learn more about Ramsey Electronics ham radio kits, write for our complete catalog. (And, be sure to tell us how youre doing with your SR-1 Receiver!) To learn more about the hobby of ham radio, write ARRL (American Radio Relay League), 225 Main Street, Newington, CT 06111. CIRCUIT DESCRIPTION The NE602 IC is a combination oscillator-mixer. Signals from the antenna are peaked by L1 and fed to pins 1 and 2. The oscillator frequency is determined by C3,C4,L2 and the varactor tuning network (D1,R2,etc.). The use of a hyper-abrupt style varactor diode permits a tuning range of over 2.5 Mhz by R2. The mixer output is applied to the 260 Khz bandpass IF transformer and amplified by Q2 and Q3. The AM audio is detected by D2 and preamplified by U2(A) before being boosted to speaker level by the LM386 IC. U2(B) and Q1 provide AGC (automatic gain control). The very low 260 Khz IF affords exceptional gain and selectivity characteristics and also offers a sort of bonus that would not be normally welcome in a receiver intended for communications and listening for very weak signals. In tuning your SR-1 receiver, it is useful to understand that you will hear any signal at the oscillator frequency PLUS 260 Khz and also at that frequency MINUS 260 Khz. This is not a problem for general listening to shortwave broadcasts, as long as you realize that youll find every broadcast twice as you pass through the 2.5+ Mhz range of the Tuning control. The circuitry required to minimize this image reception would defeat the goal of economy and simplicity intended for the SR-1. More elaborate superhet receivers deal with this phenomenon by using a higher intermediate frequency, several IF stages and very exact tuning of the antenna input circuit. However, you will find the SR-1 to give perkier reception with simple antennas than do many much more costly portable receivers. SR-1 7 SR-1 PARTS LAYOUT DIAGRAM SR-1 8 PARTS LIST CAPACITORS ?3 100 pf disc capacitors (marked 100, 101, or 100K) (C3,7,8) ?11 .01F disc capacitors (marked .01, 103, or 10nF) (C1,2,5,9,10,11,12,13,14,15,18) ?3 4.7F to 10F electrolytic capacitors (C6,17,22) ?3 100 to 220F electrolytic capacitors (C16,20,21) ?1 .1F ceramic disc capacitor (marked .1 or 104) (C19) ?1 10 pF ceramic disc capacitor (marked 10)(C23) INDUCTORS ?2 Shielded coils (marked 5015-015) (L1,L2) ?2 1800 H inductors (marked 182J)(L3) RESISTORS ?1 2 ohm red-black-gold (R16) ?1 270 ohm red-violet-brown (R5) ?2 1K ohm brown-black-red (R6,R9) ?3 10K ohm brown-black-orange (R4,R10,R11) ?3 47K ohm yellow-violet-orange (R7,R8,R15) ?2 100K ohm brown-black-yellow (R12,R13) ?1 1M ohm brown-black-green (R14) SEMICONDUCTORS ?1 1N270 diode, glass bead style (D2) ?1 Varactor diode, transistor style body with two leads (MVAM108) (D1) ?4 NPN transistors, 2N3904 or similar (Q1,2,3,4) ?1 NE602 8-pin DIP IC (U1) ?1 LM358 8-pin DIP IC (U2) ?1 LM386 8-pin DIP IC (U3) HARDWARE AND MISCELLANEOUS ?1 SR-1 printed circuit board ?3 10K potentiometers (R1,2,3) ?1 DPDT PC-mount push button switch (S1) ?1 RCA-type PC-mount jack (J1) ?1 Subminiature phone jack (J2) ?1 9-volt battery snap connector ?1 9-volt battery hold-down clamp REQUIRED, NOT SUPPLIED: ?9-volt alkaline or heavy-duty battery ?Earphone, small speaker, or external amplifier with speaker ?Antenna or suitable cable, connector, grounding OPTIONAL SR-1 9 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 parts 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. ?Trim or nip all excess wire lengths extending beyond each solder connection, taking care that wire trimmings do not become lodged in solder connections. You can see that this circuit board, the center portion in particular, is fairly well-filled with components. Theres more to this receiver than the average beginners radio or even our popular Amateur Band receivers. Follow the assembly instructions IN SEQUENCE and check off each step as understood and completed. Some of the components require modification! Examine the schematic circuit diagram and PC Board parts layout diagram as you proceed. Use good soldering techniques! Let your soldering iron tip heat both the component lead wire and PC board trace enough so that the wire itself AND the foil trace BOTH become hot enough TOGETHER to melt a bit of solder so that it flows smoothly from the pin to the PC board trace. Enough said. Lets get building! ?1. Install J1, the RCA antenna jack. Solder all 4 points. ?2. Install S1, the DC on-off switch. It fits only one way. Ensure that the white plastic switch extends out over the edge of the printed circuit board. ?3. Install C1, a .01 F (marked .01 or 103) signal coupling capacitor, which brings the antenna signal up to the front of the PC board. Notice the long PC trace from J1 through C1 to R1. ?4. Install potentiometer R1, the RF gain control. ?5. Now, its time for a little destruction! (If you jumped ahead and installed L1 and L2, weve got bad news for you). Before these two SR-1 10 shielded transformers can be installed, their internal capacitors need to be removed. Looking at the underside of these two transformers, youll 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). Youll find these capacitors will easily disintegrate into particles. DO NOT do anything to the larger dual IF transformer, L3. ?6. Install L1, which peaks or preselects the signal input from the antenna through C1 and R1. ?7. Install U1, the NE602 IC mixer oscillator. The marked end of the IC (band or dot) must face the FRONT of the PC board (the end with the switch and dials.) If you wish, install an 8- pin DIP socket, still remembering to orient and install correctly. Please dont be afraid to solder U1 directly to the PC board, as we have seen more repair problems associated with DIP sockets than from direct soldering of IC chips! ?8. Install C2, .01 F (marked .01 or
