# Questions tagged [transmitter]

Questions on a set of equipment used to generate and transmit electromagnetic waves carrying messages or signals, esp. those of radio or television.

297 questions
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I got a new HTC one m9 and it has an FM reciever in it, it picks up all the radio channels in my area really well. I am trying to make a very simple radio transmitter for the fun of it. I dot want ...
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### Is it possible to induce few volts IMPULS over 10 m distance?

I'm currently learning about electromagnetism at college, so this question is on mine mind for a few weeks. If we have on one side: 9 V battery, DC-DC converter to few kilovolts, capacitor, button, ...
204 views

Can a standard computer function as a radio receiver without additional hardware, and how? Thanks, and happy holidays.
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### strange results from transmitter radiation calculation

This table was taken from:http://www.emfwise.com/distance.php At that site a formula: Power Density = P/4Πr2 was used in order to calculate the power density(mW/m2) according to the distance from ...
108 views

I am trying to add a radio transmitter to small remote controlled airplane. I would like it to fit inside and the space I have to work with is 1.25 by 1.25 by 0.2 cm. I am wondering what sorts of ...
975 views

### IR receiver output pulsating instead of constant one('5V') or zero ('0V')

I am trying to detect the size of different bottles on a conveyor belt and for that I thought of using IR transmitter and receiver but I am not getting desired output. I want the output of IR receiver ...
333 views

### RF Transmitter and receiver circuits

I need to build a RF transmitter and receiver circuit for a class project. Size and scaleability is important. I would like it to be as close to hand held as possible for both ends. 9V power source. I'...
3k views

### How do two UARTS know which baud rate to use?

I am reading about the standard protocol for UART and I think that if the receiving UART does not have any idea on what baud rate the data was transmitted, there would be lots of problems. If the ...
1k views

### How does this FM transmitter work?

I'm an electronics student and I have been trying to understand this FM transmitter diagram (taken from electronicshub.org) for a long time. I had put efforts to learn it by surfing the web but parts ...
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### Fm tone transmitter with enable

I'm trying to make a tone transmitter that can transmit a tone at least one hundred feet in clear sight to any standard radio on a frequency where no one is broadcasting. I understand that the values ...
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### Why do receivers have a choke but transmitters don't?

Here's a receiver I found on the web: And here's a transmitter: [ Why do receivers have an inductor specifically designated as a choke (RFC) in their circuits but transmitters don't?
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### How to increase range without wasting current if possible

This is an FM transmitter that I built. I wanted to interface it with a microcontroller. The enable connection seems to work, but the range is extremely weak (about one inch), even when running off ...
619 views

### Why is the grounded capacitor smaller in a transmitter vs a receiver?

Here's an FM transmitter that I found on the web: Here's a regenerative receiver that I found: The capacitor connected to the base of the transistor in each circuit is different. Why isn't the ...
428 views

### Why do transistor transmitters not have base resistor connected to collector instead of vcc?

I was researching here on transistor amplifiers: http://www.talkingelectronics.com/projects/TheTransistorAmplifier/TheTransistorAmplifier-P1.html#Stage and they were talking about these two ...
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### What is this white device? [closed]

I know this question might sound a little silly and this is probably not the best site to ask, but I would really appreciate any answer. My neighbours installed this device just opposite to windows of ...
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### Do I need anything between a microcontroller and a basic FM transmitter to cut out EMI?

Below is my circuit of a basic FM transmitter attached to an output pin of the AT89C2051 micro controller. I haven't tested it and I might decide to connect R1 to the NPN collector instead of to VCC. ...
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### Is my bluetooth range impacted by the remaining battery on my smartphone as a scale or ratio?

Sometimes it seems my bluetooth speaker is particularly sensitive to the distance from my smartphone, sometimes it seems completely indifferent. The variable seems to the battery charge. My question ...
66 views

### UHF band repeater [closed]

I want to make a device which gets the TV antenna signals and transmits it again. Is there any module available in market which simplifies construction or i should make from scratch? Since my ...
1k views

### How to calculate telescopic antenna impedance?

I'm designing a 27 MHz transmitter for controling RC toy using TX-2B and RX-2B ICs. Thre is my output stage schematic (see attachment). Output impedance 50 Ohm. I know that antenna length on 27 Mhz ...
3k views

### Transmit a signal using RF transmitter/reciever without using microcontrol or a decoder/encoder

Objective: I am trying to build a transmitter that transmit an on signal when a button is push. The transmitter will need to be small enough to wear or hold in a pocket. I prefer not to use any ...
270 views

### can i connect two similar antennas to two ends of a cable to to re-transmit the signal received from one end?

Scenario: I've set up two wifi hot spots outside of my house at distance lesser than 20 meters as i don't get any ISP signal inside my house. But the problem is now i get very weak signal in my ...
326 views

### Encoding / Decoding solid '0' or '1' with IC (or discrete solution)

I ordered a rf 434MHz transmitter and receiver for a hobby project. It only needs to transmit a solid '0' or a '1' (this won't change more than once every 5s, probably much longer), so I thought I ...
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### Designing a matching network with biasing inductor

I'm designing a 345MHz transmitter using the MAX 7044 ISM transmitter with an electrically small antenna and need to test the matching network. I will connect the VNA in place of the transmitter using ...
387 views

### Question on replace of Inductor Coil in a FM Transmitter

I am making a 2 Watt FM transmitter. The transmitter's inductor is somewhat like this :- The resistor is part of the transmitter circuit. I am little confused with the inductor and not sure how to ...
128 views

### Complete fiber optic transmitter and receiver with standard fiber optic connector and integrated power circuitry? [closed]

I am having a very difficult time trying to find a simple, completely self-contained module to convert digital signals (<2Mbps) to fiber optic, that uses a robust, standard fiber optic connector (...
1k views

### How can I operate two ASK RF Transmitter modules(433 MHz) simultaneously without jamming each other?

Transmitting using this transmitter seems to jam many wireless devices (possibly using the same frequency) like car keyless entry remotes, garage door openers etc. Moreover, two such transmitters ...
300 views

### RF Transmitter and Receiver circuit controls

I'm trying to build a Radio controlled TX and RX circuit (using a 2.4 GHz chip and MCUs), to control a robot with four DC geared motors. I plan to use four momentary on-off-on switches on the TX ...
214 views

### How did four-course LF radio navigation ranges have their beams other than at 90° / 180° angles?

The four-course Low Frequency Radio Range system used for aircraft navigation (in the US and elsewhere) in the 1930s and 1940s used a pair of directional antenna (with figure-of-8 shaped radiation ...
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### Transmitter and receiver problems [closed]

Hi I am a construction site manager with very little knowledge in electronics. I have recently invented a new site safety device which involves the use of multiple transmitters and receivers. I ...
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What is the maximum range of a 27 MHz ISM band when transmitting at full power? I am interested in general situation for US and EU but that will go back to the power limits allowed. My country (CZ in ...
2k views

### Boost the signal of an FM transmitter using an “emitter follower” transistor [closed]

EDIT: I've seen an alert under my question: “Please clarify your specific problem or add additional details to highlight exactly what you need. “ Maybe this is due to the fact that I'm not very good ...
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### FCC cert - inactive transciever

Does the product on USA market with inactive transmitter (2,24 GHz) need the FCC certification? We are going to use Tx/Rx module, but the transmitting function will be software disabled.
336 views

### How can I reproduce ambient EM fields inside a Faraday enclosure?

I am part of a research team looking at the possible effects of EM fields on psychological function. The experiment calls for participants to perform a series of tests while inside a Faraday tent that ...
1k views

### Difference between ultrasonic transmitter sensor and ultrasonic receiver sensor?

What is the difference between ultrasonic transmitter sensor and ultrasonic receiver sensor? Can an ultrasonic receiver sensor be used as an ultrasonic transmitter sensor or vice versa?
442 views

### Turning LED lights on/off based through any wireless means

I've spent several hours researching this website for an answer to my question. The problem is i don't know the terminology or anything. So if you know the answer please treat me as an individual with ...
120 views

### Does thhis crystal circuit works?

I need a tiny oscillator circuit for testing an application. Now I haven't much experience in creating oscillators so I would like to use this Collpits-circuit: fig1 http://fs5.directupload.net/images/...
2k views

### Building an fm transmitter broadcasting simultaneously to all fm frequencies [closed]

I would like to build an FM transmitter that transmits a signal to all fm frequencies simultaneously, so that any nearby radio tuned to any frequency can receive this signal. Is it possible to do this ...
421 views

### Switching on Power to 433MHz chip

I have this 433 MHz transmitter attached to my Arduino 5v Vcc pin. I asked this question so I could deliver 12v to the transmitter chip, effectively boosting the transmitted power output, allowing me ...
2k views

### Are the same type of antennas used for receiving and transmitting?

Short version: Is the same antenna type used for transmitting as is used for receiving if the frequency is the same? Long version: My garage door opener uses 433 MHz to receive signals from the ...
162 views

### Transceiver and RF Emissions (Unintentional)

My question is simply what is RF emissions (unintentional) and how does it relate to a device (such as a smart phone) which contains a transceiver or transmitter (baseband IC) ? Which part of a RF ...
597 views

### Hacking an RC car controller to implement a joystick (PWM)

My RC car controller (transmitter) has only 4 buttons (left wheel forward /backward, same for right) I want to implement a joystick using Arduino. The Arduino will use PWM on the transmitter ...
235 views

### Questions about FM Mic Kit Schematic

I'm currently building an FM Microphone kit and I'd like to understand its operation before physically putting it together. The documentation only provides an overview of some aspects and provides no ...
2k views

### 315 MHz Reciever/Transmitter Raspberry Pi

I bought a receiver and transmitter (I can't find the link, but it says FS1000A and LR1 315.00 on it). I also have a set of remote controlled wall outlets that operate on 315MHz according to the FCC ...
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### RS232/RS485 Converter Circuit Receiving Problem

I'm trying to make an RS232/RS485 converter circuit. I used a circuit from http://airborn.com.au/layout/232cnv/232to485.html site and i changed some components on that circuit. Then I established my ...
477 views

### Wiring the antennas together in RF link 315Mhz RX and TX

I am using a 315Mhz Transmitter and Receiver RF link kit between two arduino. What happens if I wire the antennas of both RX and TX to both ends of a 1 meter long metal wire? Will using a conductor ...
136 views

### Common-Mode Voltage

I have an application which is using a differential transmitter to transmit a video signal(PAL).Transmitter is placed in a remote device which is connected through a long cable.The device is powered ...
187 views

### Locating the Origin of 2.4GHz RF Transmissions

Is it possible? How would it work? Consider IEEE 802.11 (aka.Wi-Fi); for instance. There's such an incredible amount of devices out there, measuring and reporting WLAN AP signal strength (RSSI, RCPI, ...
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### Is there anyother way to construct an FM transmitter

I recently built an FM transmitter that uses a combination of coil and capacitor as an oscillator to generate the carrier frequency. I built this transmitter: Now my problem is that I find it ...