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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3
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2answers
706 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 ...
5
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3answers
300 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 ...
1
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1answer
51 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 ...
1
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0answers
19 views

TX7316EVM +5V DC Problem [on hold]

I have a TX7316EVM development board: http://www.ti.com/lit/ug/sbou224a/sbou224a.pdf It needs 3 bench power supplies to operate which can deliever +-5VDC(.2A) on J3 connector, +-50VDC(.03A) on J1 ...
2
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1answer
71 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 ...
0
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1answer
165 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 ...
0
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1answer
179 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 ...
0
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1answer
78 views

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

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 ...
3
votes
3answers
124 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 ...
-2
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1answer
63 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 ...
0
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2answers
56 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-...
1
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1answer
50 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 ...
18
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2answers
6k 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?
5
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1answer
4k views

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. ...
0
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1answer
68 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 ...
0
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1answer
80 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 ...
2
votes
1answer
2k views

Building a small 3-axis accelerometer mote

I'd like to build a remote device which reports its current 3-axis acceleration to a nearby (<10m) receiver. It needs to be as light and as small as possible. (I have no preference as to the ...
0
votes
1answer
26 views

Rf Module Receiver With Pt2272 always gets signal

I am just trying to on and of an led with rf module. I have tried lots of module but my works end up with same result. When I feed my receiver, with led connected to data out, it always powers the ...
1
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0answers
114 views

Low latency wireless audio transmitter

I am working on a project that requires low latency wireless point to point audio transmission at short distance using a digital transmission technique (ideally 24bit 96khz audio, 30 metre max) at a ...
-9
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1answer
105 views

How to increase frequency of my rc device? [closed]

I'm presently trying to increase the distance i can use a rc device. So I want to know how I can do it?
0
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1answer
27 views

DC Free Transmission SNR

My SNR is better with DC Free transmission. Why? Example: 1.) Datasignal with DC: Datastream consisting of 0V and 1V. 2.) Datasignal without DC: Datastream consisting of -0.5V and 0.5V. The ...
4
votes
1answer
71 views

can I use a choke 150uH inductor for my AM transmitter circuit?

I am trying to develop an AM transmitter but I am having problems with getting a variable capacitor and inductor (for the rf circuit) in my location. I was able to find a choke coil with an inductance ...
3
votes
0answers
49 views

Microphonic SAW transmitter?

I built this very simple SAW transmitter, with a simple "spring" antenna for the right frequency. To test it, I tuned a portable receiver to around 433.92Mhz and fine tuned it until I heard silence. ...
0
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0answers
30 views

Frequency Modulator with sinusoidal output

I am creating a frequency modulator, all the circuits that I have looked so far on the internet are generating a Pulse wave or a Triangular wave output, so if you guys can help me to create a circuit ...
6
votes
2answers
266 views

Tube transmitter tuning

I am trying to tune/tweak/repair this transmitter for a friend of mine. It is oscillating, and it has rf power on the antenna, but it just doesn't seem as "strong" as it should be. The diagram says ...
0
votes
1answer
60 views

Tube transmitter plate current meter question

Can I install the mA meter in this schematic directly in the circuit? This is the high voltage plate supply and there is RF on it. The diagram doesn't specify if there is any circuitry to adapt the ...
1
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0answers
33 views

What causes the fail-safe bit to be set in the SBUS protocol?

What causes the fail-safe bit to be set in the SBUS protocol? I know that the when the link between the transmitter and receiver is lost, the fail-safe bit is set, however, what constitutes a 'lost ...
0
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3answers
70 views

Wire size question

I am trying to figure out AWG from a European/German schematic. The wire is listed as 0,3mm. (That's 0 (comma) 3mm.) I can find wire for sale in this diameter, but I need a reference to AWG. Is ...
0
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1answer
49 views

Can I connect transmitter output to spectrum analyser input directly?

I have a spectrum analyser, that tolerates 30 dBm 50VDC signal on its input and has internal selectable attenuator up to 40 dB. Can I connect it directly (i. e. without any external attenuators) to ...
0
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2answers
148 views

3.5 MHz 2W AM vaccum tube transmitter [closed]

What do you think of my 80m band radio transmitter I designed? Originally I though about using an Armstrong oscillator, due to its simplicity and sine wavyness, but I heard that crystals are better, ...
43
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8answers
10k views

Can a radio transmitter somehow detect the number of receivers in its area?

During conversation, a colleague proposed that over-the-air television and radio broadcasters can determine the number of viewers or listeners based on the "load" on their signal. This seems to me ...
0
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1answer
169 views

Can Pulsed DC be used in a radio transmitter?

I'm building a small radio transmitter based on a 555 timer. In my circuit a 555 timer in astable mode is used as an oscillator. kind off like : http://www.instructables.com/id/555-AM-Transmitter/ ...
0
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2answers
95 views

How to make the receiver send signal back to the transmitter with wireless RF 433MHz module

I want to buy a RF transmitter & receiver 433MHz on the internet for our research project which deals with radio frequency. I badly need the concept of having the receiver notify the transmitter ...
1
vote
4answers
141 views

How to radiate a positive oscillating voltage?

I am trying to build a simple AM transmitter, transmitting only a carrier wave and thus silencing the noise on my radio standing next to my circuit. I built this circuit on a breadboard. It's a ...
0
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1answer
98 views

How to increase range of AM radio waves? [closed]

As a personal project, I made a very simple AM transmitter with an idea from an online tutorial, using a 1 MHz crystal oscillator (plus power source, antenna, breadboard, etc.). However, when using ...
0
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2answers
241 views

Explain this circuit

I know this circuit is an oscillator circuit and it senses another signal of same frequency, but I don't understand the calculation behind it, and the reason for emitter inductor, 3.9k collector ...
-1
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1answer
238 views

FM Transmitter (Modulator) Circuit Simulation Problem [duplicate]

I've asked my question before, and I am writing this new question with some edits based on my previous problem. I am building a small FM Modulator ( Transmitting ) simulation on (Multisim). I've used ...
2
votes
3answers
675 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, ...
0
votes
1answer
68 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}\$...
1
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1answer
43 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 ...
0
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3answers
127 views

Why does the voltage induced in the receiver coil of this WPT circuit decrease when a load is added (in parallel)?

The following is a circuit that wirelessly transfers power via inductive coupling. The circuit is supposed to power a 12 V 0.15 A DC fan and a typical smartphone, which requires 5 V DC across it. The ...
0
votes
1answer
56 views

How can I make a voice transmitter receiver? [closed]

How can make a system which have two circuit. And one is place at ground floor and another is in roof. We send voice (like call) one from other by pushing a switch and vice versa. It may be wired ...
0
votes
2answers
200 views

Need help understanding simple FM transmitter

I made a simple FM transmitter following https://maker.pro/custom/tutorial/how-to-make-an-fm-transmitter and it worked! Now I need some help to understand how. My coil is made of 1 mm copper wire has ...
2
votes
1answer
818 views

Merging right & left signals to mono with op amp?

Sorry for my english i'm a young french. I want to design an audio transmitter to connect my pc to my Hi-Fi without Jack cables. For now i just want to send a mono signal because sending a stereo ...
0
votes
2answers
541 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 ...
0
votes
1answer
430 views

Low noise electret mic circuit

i wanna make a FM microphone for my guitar but the problem is that the electret mic itself output a lot of background noise even before amplifying its signal. so obviously i need a preamp circuit ...
0
votes
2answers
114 views

How to design and build RF amplifier, that work in 450Khz [closed]

I have a schematic, that is a sine generator and mixer that does AM modulation. How to design and build an RF power amplifier and build a compact antenna. The goal is to transmit signal up to 50 ...
2
votes
2answers
322 views

Is it possible to broadcast FM radio up to 500 metres? [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 ...
-1
votes
1answer
78 views

need to make a simple burst transmitter [closed]

i am looking to build a simple transmitter that will transmit on 433mhz automatically every 20ms or less. would this even be possible to make? the transmitter only needs to be simple and set off a ...
1
vote
1answer
171 views

Transmitter and Receiver antennas in mobile phones

I understand that in old cellular systems where FDD were employed, we used to have same antenna at the mobile phone (User equipment) for transmission and reception.Moreover, a duplexer was used to ...