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.

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573 views

IR Transmitter for smartphone

My understanding problem is as follows : on figure 1 for the signal 2 (noted: S2) . If I understand correctly, the LED cannot reach S2 signal because polarity. Carrier Frequency is 38 KHz let ...
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1answer
57 views

Which filter is good for GSM transmeter design Butterworth, Chebyshev or Bessel?

I have to select a filter design topology among Butterworth, Chebyshev or Bessel. Based on your experience, can you suggest which filter is the best for GSM transmitter design?
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1answer
80 views

Broadcasting channels per transmitter [closed]

Are television transmitters designed to broadcast two or more 6Mhz channels? Do commercial broadcasters do it in practice? If so, what are the limits (2, 3, 4... channels)?
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1k views

Can I make a homemade radio transmitter?

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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1answer
68 views

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, ...
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2answers
208 views

Can a standard computer function as a radio receiver without additional hardware, and how? [closed]

Can a standard computer function as a radio receiver without additional hardware, and how? Thanks, and happy holidays.
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2answers
108 views

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 ...
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1answer
111 views

small radio transmitter

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 ...
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3answers
1k 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 ...
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1answer
337 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'...
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3answers
4k 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 ...
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1answer
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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0answers
70 views

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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3answers
1k views

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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2answers
111 views

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 ...
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2answers
640 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 ...
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2answers
435 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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1answer
90 views

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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0answers
158 views

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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1answer
53 views

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 ...
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1answer
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 ...
2
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1answer
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 ...
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3answers
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 ...
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1answer
275 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 ...
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1answer
332 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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1answer
115 views

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 ...
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1answer
402 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 ...
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2answers
129 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 (...
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2answers
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 ...
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1answer
301 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 ...
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2answers
216 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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2answers
329 views

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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1answer
765 views

Maximum range of 27 MHz ISM band NLOS radio broadcast

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 ...
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2answers
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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1answer
46 views

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.
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3answers
342 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 ...
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2answers
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?
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2answers
458 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 ...
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1answer
121 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/...
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5answers
3k 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 ...
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1answer
430 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 ...
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3answers
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 ...
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2answers
168 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 ...
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1answer
603 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 ...
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1answer
240 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 ...
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2answers
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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1answer
729 views

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 ...
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1answer
480 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 ...
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2answers
139 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 ...
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1answer
196 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, ...