TELEVISION TRANSMITTER KIT Ramsey Electronics Model No. TV6C Don’t string cables through the house! Transmit your VCR or camera signal to any nearby TV set with great audio and video quality.
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Ramsey Publication No. MTV6C Price $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR TELEVISION TRANSMITTER TABLE OF CONTENTS Introduction to the TV6C ................ 4 Building your kit .............................. 4 Parts list.......................................... 5 TV6C Circuit description................. 6 Parts placement ............................. 8 TV6C assembly instructions........... 9 Testing, adjustments .................... 12 Troubleshooting guide..................
INTRODUCTION TO THE TV6C: The answer to all your TV and VCR hook-up problems is now in your hands. Your TV6C TV Transmitter kit is the handy "wireless wire" you can use to connect up the whole house for TV of your choice! The TV6C accepts normal video and audio signals from VCRs, camcorders, or TV cameras and generates a low power TV signal that can be picked up by nearby TV sets.
TV6C PARTS LIST: CAPACITORS 7 .001 uf disc (marked .001 or 102 or 1nf) [C3,4,5,6,11,14,15] 2 39 pf disc [C7,9] 1 100 pf disc (marked 100 or 101) [C10] 2 68 pf disc [C12,13] 1 220 pf disc [bottom of PC board] 1 2.2 uf electrolytic [C2] 1 100 uf electrolytic [C1] 2 1000 uf electrolytic [C8,16] SEMICONDUCTORS 1 1N4148 or 1N914 diode [D1] 2 1N4002 diode [D2,3] 4 2N3904 NPN transistor [Q1,2,3,4] 1 2N3866 NPN transistor [Q5] 1 7808 voltage regulator [VR1] INDUCTORS 1 .
CIRCUIT DESCRIPTION: Video signals from J1 are suitably terminated by the 75 ohm resistor R6 and coupled through capacitor C1 to the clamp diode D1. The clamp forces the sync pulses on the video to a fixed DC level which will reduce 'blooming' on some video scenes. Video gain pot R3 permits you to adjust the amount of video applied to the modulator section of the transmitter, its function is similar to the contrast control on a TV receiver. The bias control R7 adjusts the 'black' level of the transmitter.
TV TRANSMITTER BLOCK DIAGRAM: TV6C • 7
PARTS PLACEMENT: TV6C • 8
KIT ASSEMBLY: Each of the following assembly steps is complete in itself. This means that you: 1) Identify the component called for, 2) Insert it into the proper location on the PC board, 3) Solder its leads to the PC board and, 4) Carefully trim away the excess lead wire. As you complete each step, check it off and proceed to the next step. 1. Install switch S1 into its six holes on the PC board and solder all six pins. Ignore the other set of six solder terminals on top of the switch. 2.
12. Install R10, 10K ohm (brown-black-orange). 13. Install L2, 2.2 uh inductor (green body marked with two red bands). Modulator Section 14. Install C1, 100uf electrolytic capacitor. Electrolytic capacitors are polarized devices with a plus (+) and a minus (-) lead. This means that you must install them on your PC board in the correct direction, with the plus lead going into the plus hole and the minus lead going into the minus hole.
28. Install C3, .001uf disc capacitor (marked .001, 102 or 1nf). 29. Install R5, 4.7K ohm (yellow-violet-red). 30. Install R4, 3K ohm (orange-brown-red) 31. Install C4, .001 uf disc capacitor (marked .001, 102 or 1nf). 32. Install Q3, 2N3904 transistor. Observe correct placement of the flat side. 33. Install R2, 1K ohm (brown-black-red). 34. Install Jumper JMP1. This is a short scrap of component lead wire bent to fit into the PC board holes and soldered into place.
assembly is completed. Be sure all excess leads are trimmed away and touch up any solder joints that don't appear perfect. You may wish to brush the solder side of the PC board with a stiff brush to make sure that no loose lead trimmings or solder drippings are lodged between connections. Final Assembly: Locate the whip antenna and matching mounting screw. Insert the mounting screw through the PC board from the solder side to the component side and thread the whip antenna on to the screw.
5. Connect a VCR or other video and audio source to the corresponding inputs on the TV transmitter. Insert a tape into your VCR and press 'Play'. 6. You should now see some resemblance of a picture on your TV screen. Now adjust channel adjust coil L4 for best picture. 7. Adjust the video gain pot R3 for best 'brightness' in the picture and bias pot R7 for best overall picture. These two adjustments interact and it is best to 'fiddle' back and forth until best picture is obtained.
Troubleshooting Hints: If your TV6C does not work at all, re-check the following: • • • • • • Correct orientation of all transistor flat sides. Correct resistor placement, "that's not a 10K where a 1K should be, is it?" Proper power source of 12 to 15 volts DC, check this by actually measuring the power source’s voltage while it is connected and powering your TV6C. Proper video and audio from your source, be it a VCR or other. Correct placement of disc capacitors. Make sure the .
Other Enclosure Recommendations: While we believe that the Ramsey enclosure and knob option is a fine value for finishing off your Ramsey kit, we're happy to give you an additional suggestion. If your first goal is economy and rugged portability, you will find that the circuit board can be mounted nicely in a standard VHS videotape storage box. It will be necessary to drill some holes for mounting and knob clearance, but a suitable enclosure will result.
Here are the primary "dos and don'ts" picked from the current FCC Rules, as of May, 1990. This is only a brief look at the rules and should not be construed to be the absolute complete legal interpretation! It is up to you to operate within the proper FCC rules and Ramsey Electronics, Inc. cannot be held responsible for any violation thereof. 1. Part 15 discusses various transmitters such as "wireless microphones" (for example, the Ramsey FM-1, FM-4, etc.), cordless telephones and the like.
APPENDIX B: UNDERSTANDING LEGAL "FIELD STRENGTH" A "microvolt" is one-millionth of one volt and designated "µV" in the following explanations. The new FCC Part 15 Rules specify a maximum "Field Strength" of your transmitted signal.
For other kinds of radio services, the FCC restricts such factors as transmitter power or antenna height, which cannot really limit the possible "range" of a transmission under good conditions. By restricting the maximum field strength at a specific distance from your antenna, the FCC clearly plans for your signal to "die out" at a specific distance from your antenna, no matter what kind of transmitter power or extra-gain antenna you are using.
SUMMARY The present edition of Part 15 of the FCC rules provides detailed guidance on all aspects of using low-power transmitters. The main point is that you may not cause any interference whatsoever to licensed broadcast services and that you must be willing to put up with any interference that you may experience.
Finally, the FCC Rules call for the posting of printed notices on devices intended for non-licensed operation under Part 15 Rules. You will find such notices written up for the front or back of the instruction manual for nearly any computer or video accessory that you have seen in recent months. Consult the Part 15 Rules for the exact wording of such notices.
rear plastic plate. Insert the plate into the grooves on the base tray. With both the front and rear panels in place, secure the PC board to the bottom base tray with 4 short Phillips screws. Place any knob or button covers on the switches and pots on the front panel. Fit the top cover on and use the two long screws to hold it in place. While the kit is flipped over, stick the rubber feet on the 4 corners of the case bottom.
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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.
TELEVISION TRANSMITTER Quick Reference Page Guide Introduction to the TV6C ................ 4 Parts list ......................................... 5 TV6C Circuit description ................ 6 Parts placement ............................. 8 TV6C assembly instructions .......... 9 Appendix A, FCC Rules ............... 15 Schematic diagram ...................... 22 Ramsey kit warranty.....................
