Ramsey Electronics SP1, Manual

Page 1: ...he trick and doubles as a hands free intercom too Completely Hands free talk and listen at will Needs no battery runs off the phone line Sensitive pick up throughout the room Excellent speaker volume...

Page 2: ...plifier RAMSEY AMATEUR RADIO KITS DDF1 Doppler Direction Finder HR Series HF All Mode Receivers QRP Series HF CW Transmitters VLF1 Low Frequency SWL Converter CPO3 Code Practice Oscillator QRP Power A...

Page 3: ...S Introduction to the SP1 4 Parts list for the SP1 5 Parts layout diagram 6 Assembly instructions 7 Schematic diagram 12 Initial testing 15 Optimizing your set up 16 Understanding Speakerphones 17 Opt...

Page 4: ...ild and to customize for your own needs and decor The Ramsey Speakerphone is designed to let you stay in charge of your time on a budget Think about the difference between that call you wish or plan t...

Page 5: ...2 47K ohm yellow violet orange R7 R12 4 100K ohm brown black yellow R11 R15 R16 R17 1 68K ohm blue gray orange R5 SEMICONDUCTORS 1 MC65118 28 pin DIP speakerphone IC U1 1 LM386 8 pin DIP audio amplif...

Page 6: ...SP 1 6 SP 1 PARTS LAYOUT DIAGRAM...

Page 7: ...g out before soldering The part is then soldered securely to the board and the remaining lead length is clipped off SP1 ASSEMBLY INSTRUCTIONS We have a twofold strategy for the order of the following...

Page 8: ...only two pins are actually used in the circuit 5 Examine the subminiature jack J1 supplied for speaker connection It fits into the PC board position easily Notice that the tab nearest to the edge of...

Page 9: ...panel and therefore requires soldering the MK1 element s terminals to three short bare wires nipped from a previously installed component so that the three wires are at right angles to the MK1 lugs No...

Page 10: ...r step and go back to it after you ve built up your scrap wire supply Jumpers act as electronic bridges carrying signals over PC board traces underneath 23 Near R3 install JMP11 24 Install JMP5 25 Ins...

Page 11: ...RESS SUMMARY The schematic diagram makes it clear that building the kit consists largely of providing the supporting components for the many functions of the MC65118 IC Much of that has been done alre...

Page 12: ...SP 1 12 SP1 SCHEMATIC DIAGRAM...

Page 13: ...re that all 28 pins are visible on the solder side of the board Slightly bend the 4 outermost pins to lock the socket in place Make sure the socket is flush against the top of the board Solder all 28...

Page 14: ...umper Wire from point A to point C near D3 2 Set both S1 and S2 to their out or off position Set the volume control to a mid range point 3 Next test the modular phone cord you intend to use with the S...

Page 15: ...thing above checks out you re ready for your first Speakerphone conversation Ask someone to call you When you hear the ring on any other phone you can answer the call by pressing S1 You should be able...

Page 16: ...ents OPTIMIZING YOUR SPEAKERPHONE SET UP There are three variables to be considered in any line powered Speakerphone installation 1 Positioning of speaker in relation to the microphone 2 Your distance...

Page 17: ...our head or on a sketch pad Both stations must have speakers and sensitive microphones and be interconnected by two wires only and there can be no manual talk listen switches You must be able to turn...

Page 18: ...ovides background noise monitors which make the circuit insensitive to room and line noise hybrid amplifiers for interfacing to Tip and Ring i e the phone line the microphone amplifier and other funct...

Page 19: ...cted to the line or loop The phone line carries both audio energy AC and DC voltage T1 and T2 couple the audio signals to U1 s hybrid amplifiers pins 5 and 6 In telephone terminology hybrid is a circu...

Page 20: ...nd C21 15 Supplies bias to volume control filtered by C24 16 Time constant for TX BNM set by R11 and C16 17 Input to TX level detector on mike speaker side 18 Output of TX level detector and input to...

Page 21: ...one or more SP1 s you probably already have some handy switching ideas We ll leave those to your ingenuity To set up two SP1 s for hands free intercom service just do the following 1 Solder a jumper f...

Page 22: ...SP 1 22 PARTS LAYOUT DIAGRAM SP1 SPEAKERPHONE KIT...

Page 23: ...sistors you can pretty much be assured that the 1K ohm resistors are actually the missing 10 K parts Ramsey Electronics project kits are packed with pride in the USA If you believe we packed an incorr...

Page 24: ...AL SOLDER POINTS 242 ESTIMATED ASSEMBLY TIME Beginner 4 0 hrs Intermediate 2 5 hrs Advanced 1 5 hrs REQUIRED TOOLS Soldering Iron WLC100 Thin Rosin Core Solder RTS12 Needle Nose Pliers MPP4 or RTS05 S...