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150mW FM Transmitter: (electronic Circuit added 03/06) |
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1W portable PLL transmitter: PLL oscillator with audio limiter. (circuit added 8/06) |
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2 Transistor FM Transmitters: (electronic Circuit added 03/06) |
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3 Transistor FM Transmitters: While re are a plethora of similar 2-transistor schematics available, this one is above
average. A major improvement over little 1-transistor circuit that we've discussed previously, this transmitter consist of two stages. first transistor is used to amplify audio,
which means that microphone is now much more sensitive to sound. second one acts as an oscillator. All in all, this is an interesting project for beginners and more
experienced hobbyists alike. Use any stiff wire or telescope whip antenna, just make sure that it's not too long. Range should be about 100m or even more in open. Stability is still a
problem, though. (added 3/06) |
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400mW VCO FM transmitter: BF199, BFR91, BFR96, varicap diode BB109. (circuit added 8/06) |
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Add a signal strength display to an FM Receiver IC: 09/05/02 EDN Design Ideas / (added 3/06) The Philips
(www.semiconductors.philips.com) TDA7000 integrates a monaural FM-radio receiver from antenna connection to audio output. External components include one tunable LC circuit for
local oscillator, a few capacitors, two resistors, and a potentiometer to control variable-capacitance-diode tuning.... |
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AN-543 - Monaural FM Transmitter (DSP, 20,641 bytes): AN-543-MonauralFMTransmitter-Analog Device Application Notes
(app note added 3/06) |
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AN-543 - Stereo FM Transmitter (DSP, 26,085 bytes): AN-543-StereoFMTransmitter-Analog Device Application Notes (app
note added 3/06) |
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BA1404 HI-FI Stereo FM Transmitter: Simple BA1404 HI-FI Stereo FM Transmitter (88 |
| Battery operated FM
rebroadcast transmitter: This implementation is adapted to rebroadcast the output of a CD player, television receiver, or radio receiver. I use it so that I can move about the house
and listen to my favorite programs without disturbing others. Within and the house, I find that I can get 10 to 20 meters away from the transmitter with the small pocket FM receiver I carry in
my shirt pocket. Your mileage may vary. The transmitter as built and pictured below (the transmitter is in the blob of hot melt glue on the end of the battery holder) does not have an on-off
switch. I put a 1.5 AA cell . (added 6/07) |
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BH1417 Stereo PLL FM Transmitter: Frequency is selected with a DIP switch with 200KHz increments. Transmitter needs a
7.6MHz crystal. (circuit added 8/06) |
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Crystal Controlled FM Transmitter: (electronic Circuit added 03/06) |
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FM Radio Transmitter: (electronic Circuit added 03/06) |
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FM Transmitter (rf/2bjttx): (electronic Circuit added 03/06) |
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FM Transmitter with Opamp: L1 is 0.112uH (this tunes to the middle of the FM band, 98 MHz, with VC1 at its centre value of
33pF). L1 is 5 turns of 22 swg enameled copper wire close-wound on a 5mm (3/16") diameter former. Alternatively, you can have a fixed 33pF cap instead of VC1 and have L1 as an adjustable
molded coil (eg UF64U from Maplin). VC1 will give you a tuning range of 85 125 MHz, and a possible choice is the Philips type polypropylene film trimmer (Maplin code WL72P). Two sets of
oscillator bias resistors are given, the ones in the brackets give about 20% more RF power. Mike is our favorite Omni directional sub-mini electret (Maplin code FS43W). Ant is a (lambda / 4)
whip monopole (eg 76 cms of 22 swg copper wire). Q1 is configured as a Clapp oscillator. Frequency modulation results from the audio voltage changing the transistor's base-emitter capacitance.
(added 3/06) |
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Long Range FM Transmitters: (circuit added 8/06) |
