Ramsey_FR-220_user.pdf

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1、 220 MHZ FM RECEIVER KIT Ramsey Electronics Model No. FR220 Keep an ear on the local repeater action from your easy chair with this simple and fun to build FM receiver. Tunes the entire 220 MHz band. Ideal way to audition before buying a rig! Tunes any 5 MHz portion of the 220 to 240 MHz band. Excel

2、lent receiver for new Novice classes! Excellent performance, less than 1 uV sensitivity. Tuned input, low noise preamp stage. True Dual-conversion superhet design with 2 pole Ceramic High IF and 6 pole Ceramic low IF filters! Front Panel Volume, Squelch, and Tuning controls. Excellent receiver for b

3、eginners and seasoned pros! 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 instruction carefully guides you to a finished kit that works the FIRST tim

4、e! FR-220 2 PARTIAL LIST OF AVAILABLE KITS RAMSEY TRANSMITTER KITS FM10A FM Stereo Transmitter FM25B Synthesized FM Stereo Transmitter AM25 Synthesized AM Transmitter AM1 AM Transmitter RAMSEY RECEIVER KITS FR1 FM Broadcast Receiver AR1 Aircraft Band Receiver AA7 Active Antenna SC1 Shortwave Convert

5、er RAMSEY HOBBY KITS SG7 Personal Speed Radar SS70 Speech Scrambler TT1 Telephone Recorder SP1 Speakerphone MD3 Microwave Motion Detector TFM3 Tri-Field Meter LC1 Inductance-Capacitance Meter RAMSEY AMATEUR RADIO KITS HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer CPO3 Co

6、de Practice Oscillator 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. FR220 FM RECEIVER KIT INSTRUCTION MANUAL Ramsey Electronics publication NO. MFR22

7、0 Rev. E1 First printing: February 1992 COPYRIGHT 1992 by Ramsey Electronics, Inc. 590 Fishers Station Drive, 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 State

8、s of America. FR-220 3 FR220 FM RECEIVER KIT Ramsey Publication No. MFR220 Price $5.00 TABLE OF CONTENTS Introduction to the FR220 . 4 Circuit Description . 5 Parts List . 6 Simplified Block Diagram . 8 Parts Layout Diagram . 9 FR220 Assembly Instructions . 11 Testing and Alignment . 21 Enclosure Id

9、eas . 24 Troubleshooting Guide . 24 Notes for Advanced Users . 25 Ramsey Kit Warranty . 27 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR FR-220 4 INTRODUCTION Because all but the most expensive scanners skip over the 220 MHz band, and most Ham rigs are 144 or 440 MHz, 220 is the long forgotten child. This

10、 nifty little receiver will allow you to check out 220 at a very affordable price! When you see how uncrowded the band is, and its excellent VHF propagation characteristics, were sure youll order our 220 MHz transceiver and join in. This receiver is a good project for amateurs wishing to become more

11、 familiar with 220 Mhz FM before choosing a transceiver, or for those active on 220 who want an inexpensive receiver to take on trips, keep in a briefcase or to watch for band openings. Most Ramsey Electronics can be classified as Skill Level 1 if we use the old Heathkit guidelines for ease of assem

12、bly. That means that our kits are intended to be successful for first-time kit builders. This FR220 FM Receiver is best regarded as a Skill Level 2 project, and should not be taken lightly, even by experienced, licensed radio amateurs. Still, this step-by-step manual is written with the beginner in

13、mind, because we are well aware of the fascination with 220 MHz and its maze of repeaters holds for newcomers, which means this could be your very first kit project. The same holds true for those who just want to peek in on LOW VHF public service communications without the cost of a scanner. To be h

14、onest, wed like to see first-time builders start out with an easier kit such as the Ramsey HR-40 Forty Meter receiver before assembling the FR220, but we are confident that you can construct the FR220 successfully if you follow this manual carefully and patiently. Before beginning the project or eve

15、n studying the circuit description, it is worthwhile to develop some prior respect for how much receiver is packed onto the circuit board. The nine semiconductor devices (diodes, transistors and IC chips) give the equivalent of about 30 or more transistors and diodes. And, in addition to four induct

16、ors, a crystal and two ceramic filters, there are nearly 60 capacitors and resistors. Surely, all that should result in a decent receiver! You could easily spend twice the money plus hours of time trying to gather the equivalent parts from catalogs and still need to make your own circuit board. FR-2

17、20 5 BUILDING YOUR FR220 KIT There are just over 200 solder connections on the FR220 printed circuit board. That means your work could be 99% excellent and you could STILL have 2 or 3 cold solder points or solder bridges. Since this circuit is more sophisticated than a direct-conversion HF receiver

18、or a simple transmitter, a beginner or casual amateur could have a harder time tracing a problem due to a poor solder connection. Therefore, PLEASE take us seriously when we say that good soldering is essential to the proper operation of your receiver! ?Use a 25-watt soldering pencil with a clean, s

19、harp tip. ?Use only rosin-core solder intended for electronics use. ?Use bright lighting. A magnifying lamp or bench-style magnifier may be helpful. ?Do your work in stages, taking breaks to check your work. ?Carefully brush away wire cuttings so they dont lodge between solder connections. FR220 CIR

20、CUIT DESCRIPTION VHF signals from the antenna are amplified through the tuned input circuit (L1,C3 and L2,C4) by Q1, a microwave bipolar transistor. Q1s output is fed to the input of the SA602 IC, an efficient single-package (8- pin DIP) mixer-product detector-oscillator. The tunable oscillator sect

21、ion of the SA602 is aligned to operate at 10.7 MHz higher than the signal fed and amplified by Q1. For example, to receive 222-227 MHz signals, the oscillator must tune 232.7 to 237.7 MHz in order for the SA602s mixing capability to produce a steady 10.7 MHz output signal to the rest of the circuit.

22、 The oscillator frequency is determined by L3 and its associated capacitors, and varied by the varactor tuning network using D1 and varied by R1. The output from pin 4 of the SA602 passes through a ceramic 10.7 MHz filter, amplified by transistor Q2 and applied to input pin 18 of U2. Q3 provides AFC

23、 (automatic frequency control) by keeping the local oscillator of U1 from drifting away from an incoming signal. This is accomplished by tuning the varactor circuit in the direction opposite the drift. FR-220 6 The MC3359 IC has an internal oscillator controlled by the 10.245 MHz crystal. The 10.245

24、 MHz signal is mixed with the 10.7 MHz input from U1 to convert down to the low IF of 455 KHz. The 455 KHz IF is filtered by FL2 and then amplified by a limiting amplifier in U2. Audio demodulation takes place in the quadrature detector, with L4 adjusting the detector. The audio modulation is detect

25、ed in U2, and the background noise is used to control the squelch. U3 amplifies the audio output from pin 10 of U2 to a practical level for speaker or headphone operation. Pin 16 of U2 will ground the input of U3 when the squelch is closed. L4, a 455 KHz IF coil, permits adjustment of the 90-degree

26、voltage- current phasing (quadrature) of FL2s output to the FM detector demodulator (pin 8 of the MC3359). PARTS LIST Inductors 2 small 4 turn coils (L1,L2) 1 slug-tuned 3 turn coil (L3) 1 shielded transformer coil marked LB 53303 HK (L4) Semiconductors and ICs 1 2SC2570A or 2SC2498 transistor (Q1)

27、3 2N3904 transistor (Q2,Q3,Q4) 1 SA602 8-pin IC (U1) 1 MC3359 18-pin FM receiver IC (U2) 1 LM386 8-pin audio amplifier IC (U3) 1 Varactor diode, BB405 small black body with white band (D1) 1 1N914/1N4148 signal diode (D2) Special Components 1 10.245 MHz Crystal (Y1) 1 10.7 MHz ceramic filter brown,

28、molded, 3 leads (FL1) 1 455 KHz ceramic filter black, square (FL2) FR-220 7 Fixed Resistors 1 2 ohm red-black-gold (R22) 3 270 ohm red-purple-brown (R6,9,20) 1 470 ohm yellow-purple-brown (R5) 2 1K ohm brown-black-red (R11,12) 3 10K ohm brown-black-orange (R7,17,19) 1 18K ohm brown-gray-orange (R18)

29、 1 33K ohm orange-orange-orange (R14) 4 47K ohm yellow-purple-orange (R4,8,13,21) 1 100K ohm brown-black-yellow (R16) 1 470K ohm yellow-purple-yellow (R15) 1 1 megohm brown-black-green (R10) Capacitors 1 2 or 2.2 pf (C2,12) 4 4.7 or 5 pf (C1,5,9,10) 2 10 pf (C3,4) 1 22 pf (C19) 1 27 pf (C11) 2 100 p

30、f marked 100 or 101 (C6,22) 1 220 pf marked 220 or 221 (C18) 6 .001 uf marked .001 or 102 or 1nf (C7,8,20,23,24,25) 8 .01 uf marked .01 or 103 or 10nf (C13,16,17,21,26,28,29,31) 1 .1 uf marked .1 or 104 (C34) 1 1.0 uf electrolytic (C27) 3 4.7 or 10 uf electrolytic (C15,30,36) 4 100 to 220 uf electro

31、lytic (C14,32,33,35) Controls and Hardware 1 Printed circuit board 3 10K ohm potentiometer (R1,R2,R3) 1 DPDT push switch (S1) 1 PC mount RCA jack (J1) 1 PC mount subminiature speaker jack (J2) 1 9-volt battery bracket (B1) 1 9-volt battery snap-on clip REQUIRED, NOT SUPPLIED 1 9-volt alkaline batter

32、y 1 VHF antenna with cable terminated in RCA-style plug or adapter 1 Speaker or headphones FR-220 8 U2, 3359 FR220 BLOCK DIAGRAM U1 SA602 MIXER FR-220 9 FR220 PARTS LAYOUT DIAGRAM FR-220 10 NOTE CONCERNING THE AUDIO OUTPUT JACK Your receiver kit is supplied with a standard subminiature 2.5 mm (3/32”

33、) audio jack, which mates with commonly available earphone plugs and adapters available at Radio Shack, such as 274-290 (plug) or 274-327 (adapter for 1/8” mono plug). If you prefer to use another size and style jack, we suggest that you still install the original jack and then wire your own jack in

34、 parallel with it rather than rough up the PC board to accommodate your jack. SEMICONDUCTOR REPLACEMENT DATA U1 SA602 Contact Ramsey Factory U2 MC3359 (Motorola) ECG860 or SK7731 U3 LM386 (National) available at Radio Shack, other suppliers Q1 2SC2498 or 2570 ECG10 or SK9139 Q2,3 2N3904 available at

35、 Radio Shack, other suppliers D1 BB405 contact Ramsey Factory D2 1N4148 available at Radio Shack, other suppliers FR-220 11 RAMSEY “Learn-As-You-Build” KIT ASSEMBLY: We have a twofold strategy for the order of the following kit assembly steps. First, we install parts in physical relationship to each

36、 other, so theres minimal chance of inserting wires into wrong holes. Second, whenever possible, we install in an order that fits our Learn-As-You Build Kit building philosophy. FOR EACH PART, OUR WORD INSTALL ALWAYS MEANS THESE STEPS: 1. Pick the CORRECT part value to start with. 2. Insert it into

37、the CORRECT PC board location. 3. ORIENT it correctly, which means: PLEASE follow the PC board drawing and the written directions for ALL parts where theres a right way AND a wrong way to solder it in. (Diode bands, electrolytic capacitor polarity, transistor shapes, dotted or notched ends of ICs, a

38、nd so forth.) 4. Solder ALL connections unless directed otherwise. Use enough heat and solder flow for clean, shiny, completed connections. Dont be afraid of ANY pen-style soldering iron having enough heat to damage a component. 5. Trim or nip excess wire lengths after soldering. NOTE: Save some of

39、the longer wire scraps nipped from resistors and capacitors. These will be used to form wire jumpers (JMP1, etc.) to be soldered in just like parts during these construction steps. Now, lets start building! 1. Press S1 firmly into its six holes and solder all six pins. The switch fits the board only

40、 one way. Ignore the other set of six solder connectors on the switch. 2. Install J1, the RCA-style antenna jack. Solder all 4 points. 3. Install J2, the subminiature phone jack. Solder all three points. Be gentle and patient in inserting, so as not to damage the solder tabs. 4. Install controls R1,

41、 R2 and R3. Insert the three PC mounted controls into their positions. Check that the controls are 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 connection. FR-220 12 Also, if

42、you plan to use an enclosure other than the custom Ramsey enclosure and knob kit, you may wish to locate the controls differently than provided by the PC board. In this case, the control lugs are wired to the PC board using your own insulated hookup wire, kept as short as possible for neat installat

43、ion. FURTHER COMPONENT INSTALLATION All directions on the PC board (i.e.: right, left, above, below and so forth) assume orientation of your board as shown in the parts layout diagram. Therefore the rear of the board (connectors) is the lower end, and the front (controls) is the upper end. 1. ANTENN

44、A INPUT AND TUNED RF PREAMPLIFIER 5. Install C1, 4.7 or 5 pf disc capacitor. 6. Install C2, 2 or 2.2 pf. 7. Install C3, 10 pf. 8. Install L1, a small 4 turn wire coil. Gently stretch the coil just enough so that its two wire leads fit firmly into the PC board holes. Solder both leads securely. This

45、coil is designed to permit additional stretching or compressing as part of the alignment process. 9. Install C4, 10 pf. 10. Install L2, the other 4 turn coil just like L1 above. 11. Install C5, 4.7 or 5 pf. 12. Clearly identify Q1, the 2SC2498 or 2SC2570A transistor. Do not confuse it with the other

46、 transistors supplied. 13. Position Q1 as shown on the PC board layout, with the flat side facing to the right, toward the middle of the board. Press the transistor snugly into the PC board so that only a minimum amount of wire lead is exposed above the board. In soldering, dont be afraid to use eno

47、ugh heat to make good clean connections. 14. Install R4, 47K, just to the left of Q1 yellow-violet-orange. 15. Install C6, 100 pf (marked 100 or 101). FR-220 13 16. Install R5, 470 ohms yellow-violet-brown. 2. SA602 OSCILLATOR-MIXER and VARACTOR TUNING 17. Install R6, 270 ohms red-violet-brown. 18. Install C7, a .001 uf bypass capacitor (marked .001 or 102). In installing the SA602 IC, you may wish to use an 8-pin DIP socket rather than soldering the IC directly to the board. Reasons for d