Ramsey Electronics Model No. FR1 Build your own FM Broadcast receiver. Radio covers 70 to 110 Mhz, ideal for tuning in out-of-band FM wireless mikes, ‘bugs’ and other transmitters that exist where ‘others’ can’t find them! An added feature of the FR1 is its SCA output, which allows easy connection of SCA decoders - for commercial -free music, stock quotes, sports, etc.
RAMSEY TRANSMITTER KITS • FM100B Professional FM Stereo Transmitter • FM25B Synthesized Stereo Transmitter • AM1, AM25 AM Transmitters • TV6 Television Transmitter RAMSEY RECEIVER KITS • FR1 FM Broadcast Receiver • AR1 Aircraft Band Receiver • SR2 Shortwave Receiver • AA7 Active Antenna • SC1 Shortwave Converter RAMSEY HOBBY KITS • SG7 Personal Speed Radar • SS70A Speech Scrambler • SP1 Speakerphone • WCT20 Wizard Cable Tracer • TFM3 Tri-Field Meter • LC1 Inductance-Capacitance Meter • WEB1 Walking Electron
Ramsey Publication No. MFR1 Price $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR FR1 FM RADIO RECEIVER KIT TABLE OF CONTENTS Introduction to the FR1 .................. 4 FR1 Circuit Description .................. 5 Parts List ........................................ 6 Building your kit.............................. 8 Testing and Alignment ................. 12 Troubleshooting Tips ................... 14 Other Hook-ups............................ 15 SCA output...................................
INTRODUCTION TO THE FR1 FM RADIO RECEIVER Why you may ask does Ramsey sell a 'plain old FM radio' receiver? No better person to ask than yourself! The FR1; teaches radio theory, allows you to tune outside of the standard broadcast band (great for bugs, FM mikes and other goodies!), has easy hook up for SCA adapters, small size and is just plain fun.
CIRCUIT DESCRIPTION FM broadcast signals captured by the whip antenna or from the input jack are applied to the RF amplifier Q2, a high gain, low noise microwave style transistor. Signals are amplified about 20 dB, that's 100 times! After being boosted, these signals are routed to the SA602 mixer-oscillator chip for conversion down to the 10.7 Mhz Intermediate Frequency (IF).
RAMSEY FR1 FM RADIO RECEIVER KIT PARTS LIST CERAMIC DISC CAPACITORS: 4 .001 uf disc (marked .001 or 102 or 1 nf) [C4,5,15,27] 12 .01 uf disc (marked .01 or 103 or 10 nf) [C2,3,7,8,16,18,20,21,23,24, 28,29] 1 .1 uf disc (marked .1 or 104) [C25] 1 4.7 or 5 pf disc (marked 5 or 5K) [C1] 2 22 pf disc (marked 22) [C11,12] 2 100 pf disc (marked 100, 101, or 101K) [C6,14] ELECTROLYTIC CAPACITORS: 4 4.
HARDWARE & MISC: 1 Printed-circuit board 1 9-volt battery hold-down bracket 1 9-volt battery connector 2 RCA-style jack (antenna connector) 1 subminiature earphone jack 1 PC mount pushbutton switch REQUIRED, NOT SUPPLIED: 9-volt battery (alkaline or "heavy duty" type required) Earphone, or small speaker Antenna (whip or wire style) OPTIONAL: Ramsey Case, knob and whip antenna set, Model CRR1 or, Your own choice of enclosure and hardware.
BUILDING YOUR KIT Check off each step as understood and completed. Examine the schematic circuit diagram and PC-board X-ray illustration as you proceed. In all steps, "install" means to insert the correct component in its correct PC board holes, solder properly, and cut or "nip" away any excess wire.
13. Install R11, 47K ohm (yellow-violet-orange). 14. Install D1, varactor diode. It has a black body with green and red bands. Observe the correct positioning of the banded end by following the silkscreen. The green band is positioned as shown on the silkscreen. 15. Install C17, 4.7 or 10 uf electrolytic capacitor. Observe polarity. 16. Install C14, 100 pf disc capacitor (marked 100, 101, or 101K). 17. Install slug tuned coil L1. Time for a breather...
31. Install C5, .001 uf disc capacitor (marked .001 or 102 or 1 nf). Time for another break. We've now assembled the whole 'front-end' of our receiver. Front-end means the beginning of a receiver up to where it converts to the IF (Intermediate Frequency). 32. Install C25, .1 uf disc capacitor (marked .1 or 104). 33. Install R19, 2 ohm (red-black-gold) 34. Install U2, the LM386 audio amplifier IC chip. The LM386 is a very popular part, and with good reason.
52. Install jumper JMP3. How about another break? Everything is done except for the demodulator section. The front-end is bringing in the signal, the IF amp and filter are amplifying the converted intermediate frequency signal and the audio amplifier is waiting to drive a speaker. The only thing missing is a demodulated audio signal to amplify. 53. Install C9, 4.7 or 10 uf electrolytic capacitor. Observe polarity. 54. Install C23, .01 uf disc capacitor (marked .01 or 103 or 10 nf). 55.
TESTING AND ALIGNMENT A Hex head alignment tool is required to tune up your FR1. If you do not already have a set of plastic or nylon coil alignment tools and expect to build other radio or transmitter type kits, such tools are well worth having and can be found at any electronics store, including Radio Shack. While a hex style Allen wrench will fit the coil slug, the metal itself will drastically change the coil's inductance while it is in the slug.
8. Using your alignment tool, slowly rotate L1's slug gently so that the slug is even with the top of the coil form. (Do not force the slug; if it binds, rotate the slug back and gently 'rock it' to-and-fro as you would a thread forming tap. Slugs are by nature very brittle and will crack easily). Now carefully rotate the slug into the coil form seven turns. The slug will be in about 1/4 of an inch. Rotate the tune control until you hear an FM broadcast signal. Adjust L2 for best sound. 9.
SPEAKER SELECTION A fifty-cent' speaker, lying naked on your workbench will not give you a fair test of your FR1 audio quality or volume. Speaker quality and well-designed enclosures have their clear purposes! A reasonable speaker in a box delivers a pleasant listening volume as well as significantly improved fidelity. ADDING A POWER-ON INDICATOR Adding a simple LED power-on indicator to your Ramsey kit receiver is easy. All you need is the LED itself and a small 1K ohm resistor.
different adapter or a well designed and filtered DC power supply. PROBLEM: Signals have unpleasant distortion. SOLUTION: Quadrature coil L2 is not adjusted properly. PROBLEM: Oscillator inoperative or wrong frequency. SOLUTION: In addition to checking solder joints, be sure that L1 is tuned correctly, and the frequency determining capacitors, C11,12 are the correct values. PROBLEM: Unit receives when L1 is adjusted, but not able to be tuned with Tune control.
On weak signals it may be possible to hear the counter's busy humming action in the background, but not to a serious degree. If you decide to add such a counter connection to your receiver, remember that the coax as well as the coupling capacitor becomes part of the oscillator circuit. Make the coaxial cable connecting the counter to the receiver as short as possible. You will experience a frequency change of several hundred KHz when connecting or disconnecting up the counter.
IN CLOSING... Finally, we remind you that modifications of the kit put you on your own, voiding your Ramsey limited warranty, making your unit ineligible for factory repair. Make sure the receiver is working properly and that you understand how to use and repair it BEFORE making any changes in the original design. If you’ve enjoyed building this Ramsey kit, there are plenty more! Our nifty FM25B Stereo FM Transmitter is especially popular.
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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.
FR1 FM BROADCAST RECEIVER Quick Reference Page Guide Introduction to the FR1 ...................4 FR1 Circuit Description ...................5 Parts List .........................................6 Building your kit ..............................8 Testing and Alignment ..................12 Troubleshooting Tips ....................14 Other Hook-ups ............................15 SCA output ...................................16 Schematic Diagram ......................18 Ramsey Kit Warranty ....................
