SPEECH SCRAMBLER / DESCRAMBLER KIT Ramsey Electronics Model No. SS70A Communicate in privacy over any audio path! Full duplex operation so this unit can scramble and descramble at the same time! E-Z hookup instructions for radio, or scanner. • Uses “state of the art” digital electronic filtering for superior noise free sound! Speech inversion type system - similar to SSB.
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Ramsey Publication No. SS70A Price $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR SPEECH SCRAMBLER / DESCRAMBLER KIT TABLE OF CONTENTS Introduction to the SS70A ............. 4 Circuit Description ......................... 5 Parts List ....................................... 7 Schematic Diagram....................... 8 SS70A Assembly instructions ....... 9 Testing the SS70A ....................... 12 Hook-up Configurations ............... 13 Troubleshooting ...........................
INTRODUCTION The Ramsey SS70A is a complete two-way speech scrambler/descrambler with suitable inputs and outputs for scanner, two-way radio, cordless telephone, or tape recorder operation. It is designed to help the user secure total privacy for communications or recorded memos.
Mixer Audio In Filter Inverted audio out OSC IN Spectral display of audio inputs and outputs. Sum components are filtered, difference components are used. AMPLITUDE Desired Filtered Dif f erence Sum Audio Osc FREQUENC Y The audio input is amplified and filtered by the IC, then "mixed" with the carrier to produce both the sum and difference frequencies.
RAMSEY Learn-As-You-Build KIT ASSEMBLY There are numerous solder connections on the SS70A printed circuit board. Therefore, PLEASE take us seriously when we say that good soldering is essential to the proper operation of your scrambler! Following, are a few quick tips to make the assembly process a bit more enjoyable. • Use a 25-50 watt soldering pencil with a clean, sharp tip. Wipe the tip often on a damp sponge to keep it clean for easier soldering.
SS70A PARTS LIST Sort and “check off” the components in the boxes provided. It’s also helpful to sort the parts into separate containers to avoid confusion while assembling.
SS70A • 8
SS70A ASSEMBLY INSTRUCTIONS 1. First, install switches S1, S2, and S3. Be sure that all legs fit through the circuit board before soldering. Solder all the pins. 2. Install the volume control pot, R11. Solder the three component connections as well as the mounting pins. 3. Moving to the back of the PC board, install connector J5, the power connector. Be careful to insert all three of the connection tabs through the PC board. 4. Install the four 3.5 mm phone jacks J1, 2, 6, and 7. 5.
without "straining" the leads. Solder all three connections securely. 16. Install R12, 1K ohm (brown-black-red). 17. Install R9, 470 ohm (what colors were those?!) (yellow-violet-brown). 18. Install C12, a 10 uF electrolytic capacitor. This component is "polarized" and must be oriented correctly before soldering. The positive or ( + ) points are clearly marked on the PC board layout diagram. Study the style and markings of the capacitors supplied in your kit.
done inside the chip, this should go fairly quickly. 32. Install C6, 22 pF disc capacitor (marked 22 or 22K). 33. Install C7, another 22 pF disc (marked 22 or 22K). 34. Install Y1, the 3.58 MHz or 10.24 MHz crystal. Make sure to mount the crystal in the proper holes. 35. Install R8, 1Meg ohm (brown-black-green). 36. Examine crystal Y1, if it is a 3.58 Mhz unit, install jumper JMP7, if your crystal is 10.24 Mhz, do not install JMP7.
51. Install C18, the last 10 uF. Watch that polarity! 52. Install VR1, the 7805 voltage regulator. Orient it as shown in the parts diagram, with the metal back facing edge of the PC board as shown. This component provides a stable source of 5 volts to the MX128 IC chip, and throughout the speech scrambler. CONGRATULATIONS You have just completed your SS70A speech scrambler/descrambler unit. Take a well deserved break now. Give your eyes a rest.
Configuring the SS70A inputs: LINE LEVEL INPUT Depress pushbutton switch S3 OUT to the LINE position. SPEAKER LEVEL INPUT Set pushbutton switch S3 to the IN position to select SPEAKER level input. Configuring the SS70A outputs: LINE LEVEL OUTPUT Install the jumper block between the pins on J4 labeled “LINE”. SPEAKER LEVEL OUTPUT Install the jumper block between the pins on J4 labeled “SPEAKER”.
Set pushbutton switch S3 to the IN position to select SPEAKER level input. Install the jumper block between the pins on J4 labeled “SPEAKER” to select speaker level output. Connect the scanner’s audio output to J7, RX IN and connect your speaker to J6 RX OUT. SS-70A TX OUT TX IN RX OUT RX IN POWER Scanner or Receiver External Speaker External Speaker or Earphone TAPE RECORDER CONNECTION In hooking up a tape recorder, we’ll make use of the SS70A’s TX and RX paths.
the message back, switch the power switch to “bypass” mode to hear the scrambled message. TYPICAL TWO-WAY RADIO HOOKUP: (SS70A required at each end) The two-way radio hookup is complicated somewhat by having to pay attention to the PTT (Push To Talk) line of the radio transceiver. This line “keys” the transmitter when the button is depressed, and cannot be excluded from your wiring considerations.
TROUBLESHOOTING INSTRUCTIONS Since this circuit contains relatively few components, problems are usually due to mental errors rather than component failures. The most common errors are in assembly, especially with the IC chips. Check for solder bridges or splashes. Check your parts placement, “Hmmm... is that resistor in the correct holes?” Have the electrolytic capacitors been installed the right way? Check also for “cold” (dull or “bumpy” looking ) solder connections.
CONCLUSION We sincerely hope that you have enjoyed the construction and use of this Ramsey Kit. As always, we have tried to compose our manual in the easiest, most “user friendly” format that is possible. As our customers, we value your opinions, comments, and additions that you would like to see in future publications. Please submit comments or ideas to: Ramsey Electronics Inc.
SS70A PARTS LAYOUT DIAGRAM SS70A • 18
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.
SPEECH SCRAMBLER SS70A Quick Reference Page Guide Introduction to the SS70A .............. 4 Circuit Description.......................... 5 Parts list ......................................... 7 Schematic diagram ........................ 8 Testing the SS70A ........................12 Hook-up configurations .................13 Troubleshooting ............................16 Parts Layout Diagram ...................18 Ramsey kit warranty .....................
