Ramsey Electronics FR146 manual

2 METER FM RECEIVER KIT Ramsey Electronics Model No. FR146 Keep an ear on the loca l repeater action f rom your easy chair with this simple and fun to build FM receiver. Tune the entire 2 Meter band or the VHF high Police and Fire band. • Tunes any 5 MHz portion of th e 136 to 175 MHz band. • Excellent performance, less th an 1 uV sensitiv ity.[...]

FR146 • 2 P ARTIAL LIST OF AVAIL ABLE KITS RA M SEY TRA NSMIT TER KI TS • FM10 A FM Stereo Tr ansmitter • FM100B Pr ofessional FM Transmi tter • FM25B S yn thesiz ed FM Stereo Transmi tter • AM25 Synthesized AM Transmitter • AM 1 AM T r a n s m i t t e r RAMSE Y RECEI VER KI TS • FR1 FM Broa dcast Receiver • AR1 A i rcraft Band Rece[...]

FR146 • 3 FR146 2 METER FM RECEIVER KIT Ramsey Publication No. MFR146 Price $5.00 TABLE OF CONTENTS I ntroduc tion to the FR 146 ... ........... 4 Circ uit Descr iption ....... .................. 5 Parts List ....................... ................. 6 Simplified Block Diagram .............. 8 Parts La yout Diagram .................... 9 FR146 A [...]

FR146 • 4 INTR ODU C TION TO TH E FR 146 FM REC EI VER Most Ramsey kits can be classified as “Skill Level 1”. That means that our kits are intended to be sucessful for first-time kit builders. This FR146 FM Receiver is best regarded as a “Skill Leve l 2” project (or at least Level 1.4 6!) and should not be ta ken lightly, even by experien[...]

FR146 • 5  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 don't lodge between solder connections. FR146 CIRCUIT DESCRIPTION VHF signals from the antenna are amplif ied through the tuned in put circu[...]

FR146 • 6 PA RTS LI ST Inductors  2 small 1 1/2 turn coils (L1,L2)  1 slug-tuned 3 1/2 turn coil [orange color] (L3)  1 shield ed transf ormer coil [marked LB 53303] (L4) Semiconductors and IC's  1 2SC2498 or 2SC2570A transistor (Q1)  3 2N39 04 transistor (Q2,Q3,Q4)  1 SA602 8-pin IC (U1)  1 MC3359 18-pin FM rece iver IC[...]

FR146 • 7  3 4.7 or 10 uF el ectroly tic ( C15,30,36)  4 100 to 220 uF electrolytic (C14,32,33,35) Controls and Hardware  1 Printed circuit board  3 10K ohm potentio meter (R1,R2,R3)  1 DPDT push s witch (S1 )  1 PC m ount RCA jack (J1)  1 PC m ount subminiature spea ker jack (J2)  1 9-volt battery bracket  1 9-volt bat[...]

FR146 • 8 U2, 3359 FR146 BLOCK DIAGRAM U1 SA602 MIXER[...]

FR146 • 9 FR146 PARTS LAYOUT DIAGRA M[...]

FR146 • 10 RAMSEY “Learn-As-You-Build” KIT ASSEMBLY: We have a twofold "strategy" for the orde r of the following kit assembly steps. First, we install parts in p hysical relationship t o ea ch other, so there's m inima l chance of inserting w ires into w rong holes. Second, whenever possible, we install in an order that fits o[...]

FR146 • 11 FURTHER COMPONENT INSTALLATION All "directions" on the PC board (ie: righ t, left, above, below and so forth) assume orientation of your board as shown in the parts layout diagram. Theref ore th e rear of t he board ( conne ctors) is the lower end, and the front (controls) is the upper end. 1. ANTE NN A I NP UT AN D TU NED RF[...]

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FR146 • 14 dot, or notch. Before soldering, make su re that the IC or sock et is perfec tly fflat against the top of the PC board. Install U1, the SA602, in accord with the preceding directions. ❒ 19. Install FL1, th e ceramic filter. This component looks like a capacitor with 3 leads and may be installed either way. ❒ 20. Install jumper w ir[...]

FR146 • 15 PROGRESS SUMMARY So far, you have wire d t he tuned input from the antenna, the RF preamplifier, and the SA602 mixer- oscillator, including the vara ctor tuning circuit. The work you have done has actually formed a simple receiver capable of tuning in VHF signals of all kinds and converting them to a low-level 10.7 MHz ou tput t o be a[...]

FR146 • 16 4. MC3359 FM IC and A SSOCIATED COMPONE NTS ❒ 55. Install R17, 10K ohms [brow n-black -orange] ❒ 56. Install R14, 33K ohms [ora nge-orange-orange] ❒ 57. Install C24, .001 uF [m arked .001 , 102, or 1 nF]. ❒ 58. Install C25, .001 uF [m arked .001 , 102, or 1 nF]. ❒ 59. Install C2 6, .01 uF [m arked .0 1, 103, 10 nF ]. ❒ 60. [...]

FR146 • 17 ❒ 73. Install R16, 100K ohms [brown-black-yellow]. ❒ 74. Install R15, 470K ohms [yellow-violet-yellow]. 5. FINAL CONNECTIONS: THE LM 386 AUDIO IC STAGE You now have a wo rking FM receiver ready for adjustment. The output of the MC3359 FM IC simply needs to be boosted to listening level. A few more connections, an d your re ceiver w[...]

FR146 • 18 TESTIN G, ALIG NMEN T A ND AD JUSTMENT To prepare the FR146 FM VHF Receiver for reliable monitoring operation, y ou will need these basic tools: ❒ 1. A usef ul VHF sign al source. ❒ 2. Hexagonal, non-met allic coil slug alignment tool f or L3. ❒ 3. Small screwdriver to adjust L4. 1. Signal source: This signal can be from y our t [...]

FR146 • 19 Further alignment now consists of adjusting the oscillator coil L3 to permit the tuning control (R1) to cover the 5 MHz . segm ent betw een 135 and 175 MHz of primary interest to you. Assuming y ou wish to adjust for the Two Meter 144-148 MHz Amateur Band, adjus t L3 until you hear your i ntended test signal . If you are a beginner wit[...]

FR146 • 20 Locating the LED immediately above the on-off switch is logical and ideal. The simplest way to make a good installation is to drill a neat hole ju st slightly smaller than the diameter of the LED. Then, en large the hole a little bit at a time just enough to let the LED be pressed in and held firmly . The resistor may be connected to e[...]

FR146 • 21 FR146 TROUBLESHOO TING HINTS Ramsey FR-series FM receivers are among our most widely-used and popular kits. The circuit itself, assembly and us e are "cut-and-dried." If y our receiver does not work, there is probabl y either an error in assem bly or a def ective part. Following is som e help in ca se you experienc e dif ficu[...]

FR146 • 22 hearing about significant performance i mprovements, we do no t recom mend casual modification attempts. Howeve r, there is one practical custom ization which could be un dertak en by experienced VHF experimenters w ho wish to take advantage of the NE602's ability to accept a cr ystal resonator inst ead of the exi sting L-C tank c[...]

FR146 • 23 The Ramsey Kit Warranty Ple ase read caref ully B EFORE ca lling or writ ing in abou t your k it. Most prob lems can be solv ed w ithout contac ting the f acto ry. Notice that thi s is not a "fine print" warranty . W e w ant you to u nders tand your righ ts and ours too ! All Ramsey kits w ill work if assemble d properly. The[...]

R146 • 24 FR146 2 Meter FM Receiver Kit Quick Refer ence Page Guide I ntrodu ction to th e FR146 .......... ..... 4 Circ uit Descr iption ....... ................... 5 Parts List ................................... ..... 6 Simplified Block Diagram ............... 8 Parts La yout Diagram .................... 9 FR146 Assembly Instr uctions ........[...]