6 METER FM RECEIVER KIT Ramsey Electronics Model No. FR6 Check out the 6 meter action with this simple and fun to build FM receiver. Receive crystal-clear signals from thousands of miles away! Six meters is a fascinating band! Tune the entire 6 Meter band or the VHF low Police and Fire band. • Tunes any 5 MHz portion of the 40 to 60 MHz band. • Excellent performance, less than 1 uV sensitivity. • Tuned input, low noise preamp stage.
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Ramsey Publication No. MFR6 Price $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR FR6 6 METER FM RECEIVER KIT TABLE OF CONTENTS Introduction to the FR6 .................. Circuit Description ......................... Parts List........................................ Simplified Block Diagram .............. Parts Layout Diagram.................... Schematic Diagram ....................... FR6 Assembly Instructions ........... Testing and Alignment................... Enclosure Ideas...........................
INTRODUCTION FM and repeaters on 6 meters? You bet! There's not a lot to say about using the FR6 receiver once its been correctly built and aligned. If 6 meters is "dead”, it resembles the usual 2 meter action. If 6 meters is "hot", you’ll find an amazing variety of crystal-clear FM signals from many thousands of miles away! If there are local 6 meter repeaters in your area, the FR6 will be just as active as the local repeater gang.
BUILDING YOUR FR6 KIT There are just over 200 solder connections on the FR6 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 or a simple transmitter, a beginner or casual amateur could have a harder time tracing a problem due to a poor solder connection.
practical level for speaker or headphone operation. Pin 16 of U2 will ground the input of U3 when the squelch is closed. L4, a 450 KHz IF coil, permits adjustment of the 90-degree voltage-current phasing ("quadrature") of FL2's output to the FM detector demodulator (pin 8 of the MC3359). PARTS LIST Inductors 2 .
4 4 1 6 8 1 1 3 4 62 pF (C3,4,9,10) 100 pF [marked 100, 101, or 101K] (C6,11,12,22) 220 pF [marked 220 or 221] (C18) .001 uF [marked .001 or 102 or 1 nF] (C7,8,20,23,24,25) .01 uF [marked .01 or 103 or 10 nF] (C13,16,17,21,26,28,29,31) .1 uF [marked .1 or 104] (C34) 1.0 uF electrolytic (C27) 4.
FR6 BLOCK DIAGRAM U2, 3359 FR6 • 8
FR6 PARTS LAYOUT DIAGRAM FR6 • 9
FR6 • 10
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 other, so there's 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.
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 installation. All "directions" on the PC board (ie: 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. ANTENNA INPUT AND TUNED RF PREAMPLIFIER ❒ 5. Install C1, 10 pF disc capacitor. ❒ 6.
improper socket insertion than from soldering heat damage to IC's. Even if this is your first IC, don't be afraid to use enough heat to make 8 clean connections, but DO be sure to correctly orient the end marked by a band, dot, or notch. Before soldering, make sure that the IC or socket is perfectly flat against the top of the PC board. ❒ 19. Install U1, the SA602 in accord with the preceding directions. ❒ 20. Install the FL1 ceramic filter.
❒ 37. Install jumper JMP1. ❒ 38. Install jumper JMP3. PROGRESS SUMMARY So far, you have wired the tuned input from the antenna, the RF preamplifier, and the SA602 mixer-oscillator, including the varactor tuning circuit. The work you have done so far 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 output to be amplified by Q2. This is a good time to review the steps completed so far before proceeding.
❒ 50. Install C28, .01 uF [marked .01, 103, or 10 nF]. ❒ 51. Install R19, 10K ohms [brown-black-orange] ❒ 52. Install jumper wire, JMP2. ❒ 53. Install C34, .1 uF [marked .1 or 104]. ❒ 54. Install R21, 47K ohms [yellow-violet-orange]. ❒ 55. Install C35, 100 to 220 uF electrolytic, observe polarity. ❒ 56. Install R20, 270 ohms [red-violet-brown]. ❒ 57. Install Q4, 2N3904 transistor. 4. MC3359 FM IC and ASSOCIATED COMPONENTS ❒ 58. Install R17, 10K ohms [brown-black-orange]. ❒ 59.
❒ 70. Install C19, 22 pF. ❒ 71. Install Y1, the 10.24 MHz. crystal. No special procedure is required. Simply press the crystal firmly into its holes as far as it will go, and make good solder connections. ❒ 72. Install FL2, the 450 KHz filter. Its three leads are delicate and fit in only one way. ❒ 73. Install C23, .001 uF [marked .001, 102, or 1 nF]. ❒ 74. Install C27, 1 uF electrolytic, observe correct polarity. ❒ 75.
❒ 83. Install the battery snap terminal in the two holes below S1, making sure that the positive (red) lead is inserted into the (+) hole on the PC board. ❒ 84. The battery bracket may be attached in a variety of ways. A wire jumper can be passed through the two holes on the PC board, then both ends soldered on the underside of the board. You may prefer to use very small screws or even a double-sided mounting adhesive strip or glue.
TESTING, ALIGNMENT AND ADJUSTMENT To prepare the FR6 FM VHF Receiver for reliable monitoring operation, you will need these basic tools: 1. A useful 6 meter signal source. 2. Hexagonal, non-metallic coil slug alignment tool for L3. 3. Small screwdriver to adjust L4. 1. Signal source: This signal can be from your test bench equipment or from a "live" source such as a local repeater.
7. Turn the power ON. 8. Turn R2 (Volume control) until you hear some noise. 9. Adjust L4 for maximum noise in the speaker. Further alignment now consists of adjusting the oscillator coil L3 to permit the tuning control (R3) to cover the 5 MHz. segment between 50 and 54 MHz of primary interest to you. Assuming you wish to adjust for the Six Meter Amateur Band, adjust L3 until you hear your intended test signal.
Study the PC traces between the positive battery supply wire and the on-off switch. The unused connectors on top of your switch are an ideal point to get the + DC voltage needed for the anode (longer lead) of the LED. Plan where and how you wish to install the LED in your enclosure. 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 just slightly smaller than the diameter of the LED.
suited for Ramsey amateur kit boards is Radio Shack No. 270-253A. This metal utility cabinet can accommodate both a receiver and transmitter board, plus speaker, with room for various refinements you might like to add. FR6 TROUBLESHOOTING GUIDE The Ramsey FR-series FM receivers are among our most widely-used and popular kits. The circuit itself, assembly and use are "cut-and-dried." If your receiver does not work, there is probably either an error in assembly or a defective part.
SOME NOTES FOR ADVANCED USERS Unlike Ramsey HF receivers and transmitters, the FR-series of VHF receivers do not offer much PC board space or real need for customization or other modifications. These receivers do what they are intended to do at the lowest price that we are aware of for a tuneable VHF FM receiver with squelch, AFC and generous audio output. Therefore, while we are certainly interested in hearing about significant performance improvements, we do not recommend casual modification attempts.
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.
FR6 6 Meter FM Receiver Kit Quick Reference Page Guide Introduction to the FR6 ..................... 4 Circuit Description ............................. 5 Parts List ........................................... 6 Simplified Block Diagram .................. 8 Parts Layout Diagram ....................... 9 FR6 Assembly Instructions ............... 11 Testing and Alignment ...................... 18 Enclosure Ideas ................................ 20 Troubleshooting Guide .....................
