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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18 views

Which 433MHz transmitter module can be used for battery operated wireless communication having vey low current consumption (less than 5mA)

Im designing a wireless water level controller. The WLC detects water between overhead and underground tank. The transmitter will be situated at each of the tanks. After water level sensing , the ...
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1answer
142 views

How to drive a HFBR-1541 optical transmitter?

I want to drive a HFBR-1541 optical transmitter (see page 7; 60mA output current), and I want the driver to have extended operating temperature range (at least starting from -20 degrees Celsius). The ...
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2answers
56 views

Calculating capacitor capacitance between collector and emitter in radio circuits

In many radio transmitters and receivers there is a capacitor between emitter and collector. As shown in this answer this capacitor gives positive feedback to prevent decay. My question is that, how ...
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1answer
1k views

FM Transmitter Circuit

I'm trying to make a FM transmitter work properly. I built the following circuit : I can synchronize with 94.8Mhz channel on any FM radio, I know that because the original sound from that radio is ...
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59 views

Short range FM transmitter

I made this FM transmitter from this video (https://youtu.be/joFourugXvs) but it has a very short range (30 cm). Where's my mistake?
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1answer
170 views

Friis transmission equation (log scale calculation)

I am trying to understand the Friis transmission equation. My scenario: I consider transmit antennas (\$T_x\$) and receive antennas (\$R_x\$) at a distance R [km]. f [GHz], \$G_{T_x}\$ and \$G_{R_x}\$...
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1answer
37 views

How to make the HT12E transmit (TE to low) only when one or both buttons are pressed?

I followed this video: https://www.youtube.com/watch?v=-xK0B_bM-yk and made these circuits: Transmitter: Receiver: And they work as I want them to. I have 2 pushbuttons so when one or both of them ...
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1answer
43 views

pulse transmitter operation

I'm trying to get a better understanding of how this 1.5v pulsing transmitter works. I found it on Youtube and modeled it up with some success. https://www.youtube.com/watch?v=aLS9DsF2ilg The ...
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6answers
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How to end sending data over I2C by Slave or Master?

Let us say a Slave or Master is sending multiple bytes to the receiver on I2C bus and the number of bytes is not defined before hand. So then how will the sender tell the receiver that it has no more ...
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1answer
67 views

FM modulation, amplitude problem

I'm trying to make an FM modulation with a Hartley oscillator that oscillates at 45MHz. The problem is that it's supposed to have an unitary gain. I can't find a good adjustment between a really low ...
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4answers
69 views

FM Transmitter oscillation problem

I've been trying to get this simple FM transmitter to work over the past few days and I could use some help in a few areas. First iteration was on a breadboard with all parts included. The ...
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1answer
21 views

RF modules flickering

I have an rf transmitter and receive set up on a basic circuit so that when I connective data pin of the transmitter to the 5v, the receiver should detect it and the LED turns off. This mostly works ...
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2answers
206 views

4g transmit from a tv antenna to an indoor antenna

We have a TV antenna on the roof, works on 5-2600 MHz. Its cable runs from roof to my room, connected to the TV. I am wondering if I could transmit 4g signal using another antenna, by connecting a ...
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3answers
159 views

Schematics RF transmitter

I'm attaching a schematic of an RF transmitter made by Synoxo. Chip is the SYN115. The schematic is found in the datasheet. I do not understand why L3 which is the PCB antenna (pointed with the red ...
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2answers
137 views

How to transmit a 125kHz signal?

I want to transmit a 125 kHz signal. The square wave signal is generated by the microcontroller (just transmitting no data and no receiving,) the transmitting and receiving antennas are tuned to ...
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24 views

What code rate is required for cellular transmission?

I've been doing some reading about various error correcting codes in wireless communications such as Hamming and LDPC. Since there is a trade-off between code rate and robustness, I am curious how ...
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2answers
102 views

AM modulation stage for small transmitter

I am trying to build an AM radio transmitter. I have built a Colpitts oscillator with a 7 Vpp output and an audio stage with a 1 Vpp output. I am trying to build the amplitude modulation stage I am ...
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1answer
245 views

Power transformer question in vacuum tube circuit

I am having trouble wrapping my brain around this power transformer circuit. I must be missing something very fundamental, so I apologize in advance for that. Can someone explain to me why the center ...
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1answer
35 views

Maximum transmit power allowed for 802.11g

I'm learning about the 802.11 regs. In a book I'm using, "CCNA Wireless 200-355 Official Cert Guide (Certification Guide) 1st Edition by, David Hucaby (Author). Page 53", it has the following clause ...
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2answers
39 views

Fast Ethernet transmitter structure

Does anyone knows internal structure of a typical Fast Ethernet 100BASE-TX transmitter? I wonder how MLT-3 voltage levels are formed and what can cause abnormal voltage levels at the PHY output? ...
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3answers
74 views

In Amplitude Modulation transmission, why do we need to mix (multiply) rather than just add the carrier and base-band?

Why is it necessary to mix the carrier with the message signal to create the sum and difference of the frequencies when you can just add both signal? Not only is it much easier to achieve but it would ...
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1answer
139 views

Making a Remote Control for My TV from Scratch

This might seem silly to many of you, but I lost my TV remote when I moved awhile back and instead of buying a universal remote for cheap, I want to make a remote for my TV from scratch myself. I'm ...
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2answers
611 views

Broadcast range of an FM radio station with given transmit power [closed]

I'm buying FM transmitter 0.2 watt at Lazada to broadcast for my village community at my area. Not a normal small FM transmitter for car or portable low watt (about 10mW-100mW) which broadcast up to ...
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2answers
91 views

Relationship between radio transmitter output power and its input electrical power?

Given a radio station of a given licensed effective radiated power, is it the case that the transmitter requires at least that much mains power to run it? E.g., if a radio station says it's 100,000 ...
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10answers
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Best practice in transmitting sensor analog signal over longer distances (approx. 100') — in cost sensitive products for microcontrollers

I'm looking for best practices for transmitting an analog sensor signal over long distances to a microcontroller such as the Arduino running at 3.3v or 5v. Keeping costs low is imperative. SPI and ...
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4answers
777 views

What are the basics I need to know to power LEDs with RF at a range of 30 feet?

I would like to light up a path in the woods with hundreds of LEDs using RF. The idea is that I would carry a RF transmitter powerful enough to light LEDs. As I approach the LEDs would get brighter, ...
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1answer
287 views

Building a telephone spy

I am implementing the following circuit but I am stuck at one point. How can we input the wires in IN1 , IN2, OUT1, OUT2? I don't know which wire to insert because there are almost 4 or 5 wires ...
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3answers
257 views

Best way to amplify 3.3V square wave at 1MHz to 10V square wave at 1MHz

I am trying to build a bus transmitter complying to 1553 standards. Its input is a 3.3V square wave at 1MHz (CMOS data) and it has to be amplified to 10V or higher at the same frequency. The load ...
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3answers
1k views

How does this fire alarm system transmit data on two-wire?

In the fire detection industry, analogue addressable systems use control panels and detectors (and devices such as interfaces) which communicate with each other by means of a protocol. What protocol ...
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1answer
254 views

Creating a wireless transmitter/receiver for off-the-shelf siren

Since I oddly enough haven't been able to find a suitable off-the-shelf product that's reasonable priced (less than 50-60 EUR/USD) and somewhat good looking with Google, I'm about to try a small ...
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4answers
5k views

Can a RF 433.92 Mhz transceiver communicate to a RF 433.42 Mhz Receiver?

I am working on automating my Somfy Blinds. The idea is to avoid using the remote control which works on 433.42 Mhz and use a simple RF transmitter and an Arduino. The thing is that I can not find any ...
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53 views

RFID spoofer with extended range

I have recently found this tutorial online about making a simple RFID spoofer, using only Arduino, used paper roll, coil wire and some passive components. I thought it was pretty neat and decided to ...
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1answer
7k views

How can I modify the frequency of a simple 433mhz transmitter module?

How can I change the frequency of a simple RF transmitter? These are the transmitters in question: Background Research On this question s3c says: To change the ...
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1answer
41 views

ensuring transducer (transmitter) and receiver polarity

I am trying to implement a simple phased array of 7 transmitters rated 40 kHz. I have a few receivers to measure the acoustic field generated to validate if it works. What is a simple way to measure ...
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1answer
15k views

Creating a home made ultrasound transducer

I don't know how ultrasound transducers (transmitters) are made, is it possible to create a home made ultrasound transmitter with a custom specific range 1MHz or more? If it is not, would a 3D ...
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79 views

How can we actually use PPM output from a RC receiver

I'm using FS-CT6B transmitter with R6B receiver. I have seen many code examples and tutorials for reading PPM output from R6B using Arduino Uno. In some of them, only one pin is used (external ...
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1answer
155 views

How to transmit complex numbers from USRP B210 using two antennas simultaneously? [closed]

I am using one USRP B210 board with two transmission antennas as my transmitter and another USRP B210 with single antenna as my receiver. My goal is to transmit a file such that I am using both the ...
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1answer
70 views

Can long-range radio waves from an RTV tower penetrate thin plastic composite material next to its source?

We are currently developing a conceptual design for the renovation of Croatia's main RTV tower located on 1033 meter tall peak Sljeme at the Medvednica mountain north of Zagreb. The idea is to ...
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2answers
755 views

Determining type of modulation

The circuit below is a radio transmitter circuit of a typical RC car. The circuit makes use of IC TX2 encoder. The output of IC ("SO" pin) is a series of pulses at low speed (84 Hz). This signal will ...
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3answers
380 views

Strange-looking FM transmitter circuit

I found this simple FM transmitter circuit: I built it an it works rather nicely. There are many simple FM transmitter circuits on Google, most of which look basically like this: These work by ...
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1answer
172 views

Collector-Base capacitance in simple FM transmitter

Here is a schematic of a simple FM transmitter. I understand that this work in the following way: the sound picked up by the mic is translated into a voltage at the base of the Q1 transistor. As the ...
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1answer
406 views

Tube Transmitter Issues

I'm back working on my friend's 807 tube transmitter. I've had some previous posts on this and I'd like to thank all the people who responded for your help! I bought an oscilloscope and a dummy load ...
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3answers
165 views

Improving the quality of an optical audio transmitter

I wired up a very simple device in which I use an audio signal transformer (EI14) to modulate the intensity of a laser beam (a cheap 650nm, 5mW diode) according to the audio output of my phone. The ...
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1answer
68 views

How to transmit a signal to a point [closed]

I have a signal generator (Digital Dual Channel Funktion Signal Generator) and want to generate two signals (530 and 550 Khz signal) and want to transmit these generated signals to the points on a ...
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2answers
142 views

Is a coil FM transmitter frequency affected by my body static?

I've built this coil FM transmitter following these guides which are essentially the same: https://maker.pro/custom/tutorial/how-to-make-an-fm-transmitter https://www.instructables.com/id/The-...
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1answer
56 views

Transmission of serial data characters

On a serial data link characters are transmitted data rate of 9600 baud. if characters are 8 bits and there is one start bit and one stop bit per character, then what is the number of characters ...
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9k views

Can I break a radio tranceiving device by operating it with no antenna connected?

People tell me I shall not use my CB-radio station without an antenna connected or it will result in damage of the device. Is this true and why is this?
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FM Transmitter Modulation

I am designing an FM transmitter as a learning experience and for fun, but I am having some difficulty with FM modulation. I am using a VCO with a Colpitts topology and common emitter configuration. ...
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1answer
78 views

How frequency is modulated in FM transmitter circuit [duplicate]

I am new to looking at FM transmitter and have a few questions regarding the FM Transmitter circuit below. Please break down your answers as simple as possible as I am not as well versed in circuits ...
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1answer
162 views

Trouble using a generic 4-20mA to 0-5V board to connect transmitter to Arduino

I'm doing a big project, where I will connect a lot of sensors to my Arduino Mega 2560. Eagerly, I bought boards of this type, but I can't get them to give me any voltage output! I've connected them ...

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