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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195 views

Adjusting 300Mhz FM transmitter values for max legal power/range in canada

I read a law for canada and it states: Industry Canada permits transmitters that have an output lower than 100 µV/m at 30 meters (approximately 1 microwatt output). Now what fools me are these ...
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1answer
312 views

Will a RF IC transmitter work without any antenna?

The IC is this one - https://www.silabs.com/documents/public/data-sheets/Si4012.pdf It seems i have set it up correctly according to its I2C dialog with the MCU, but nothing gets received by my SDR. ...
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1answer
152 views

Smaller ultrasonic transceiver

I am a beginner working on my Arduino-based proximity sensor array project, like this one. I have already tested the functionality with single HC-SR04 transmitter/receiver and now I would like to ...
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2answers
178 views

Microprocessor & sub 2.4GHZ transmitter for underwater application

I am looking for a device that has following properties: Can transmit data underwater (sub 2.5GHz,1-2m below surface) Very small (max. 15mmx15mmx2mm) In-built microprocessor Able to read sensors So ...
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4answers
696 views

practically how to estimate the exact distance between transmitter and receiver in wireless network [closed]

I want to know the estimation of exact distance between transmitter and receiver in wireless networks. Can the distance be calculated? What would I have to do to find the exact distance?
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1answer
107 views

Multiple antennas vs signle antenna

I have a radio transmitter (for my quadcopter) and I wanted to improve its range. So for now I removed its integrated antenna and I soldered a male sma connector so I can plug in any antenna I want. I ...
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1answer
517 views

How to design a 10GHz PCB antenna

I am a newbie in antennas generally, although I have a good grasp on electromagnetism and the physics involved around the topic. What I want to do is to build a system that will be emitting a wave ...
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2answers
560 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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2answers
6k views

What is the advantage of differential Manchester

I can see the advantage of Manchester code over NRZ: you get clock and data in one signal combined. But what does differential Manchester add to that?
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1answer
97 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
318 views

Best communication option for multiple arduinos?

My father and I want to develop a cow pedometer to measure a cow's activity. The idea is that if you can measure a cow's activity you can detect when she enters heat. Detecting heat with sensors will ...
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1answer
163 views

Stability of crystal and crystal-less oscillator transmitters

I have stumbled upon this very cheap so called "crystal-less" RF transmitter: http://www.mouser.com/ds/2/368/Si4012-35123.pdf It says there on page 5 the Carrier Frequency Accuracy is 250 ppm while ...
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2answers
879 views

Can I use a DAC to tune a VCO?

I found some FM transmitter circuits with the MAX2606 VCO. Example: Can I replace R1 with the DAC output from an AVR microcontroller? Or can I connect the DAC directly to Pin 3 of the MAX2606?
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1answer
625 views

High Frequency Oscillator

I have been experimenting with the BiPolar Transistor transmitter circuits. They worked well on the 88 - 100 MHZ Range. I am now looking to increase the frequency to about 1-2 GHZ. I cant find a ...
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2answers
596 views

On/Off Transistor Switch by pulses of Voltage

So I have a remote switch to control a light bulb. The transmitter circuit basically consists of: -transmitter IC ( RF 433M Hz) -DC power supply -Switch ( turn on/off by applying voltage, ...
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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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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
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
67 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
793 views

Separate antenna for radio transmitter and receiver

I am building a HAM radio. Do I need a separate antenna for transmitter and receiver? I will be using 20m band and voice communication (No Morse code). My primary requirement is that I should be able ...
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2answers
206 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
6k views

What technique can I use to focus a Bluetooth 4 transmission (or at least shield it)?

I'm actually trying to focus an iBeacon that uses Bluetooth 4.0 LE. These transmit in the ISM band from 2.4 to 2.485 GHz. Normally these things radiate in a spherical, or half spherical pattern, but I'...
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1answer
330 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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2answers
107 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
108 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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2answers
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 ...
2
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3answers
982 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
336 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
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 ...
3
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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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2answers
25k views

How do I calculate the frequency of an FM transmitter circuit?

Below is an FM transmitter circuit I found on the web that I would like to build from scratch: How I would calculate the carrier signal frequency so that I know where to tune my FM radio? If I want ...
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0answers
69 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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5answers
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 ...
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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
624 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
431 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
157 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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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
52 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
271 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
114 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
394 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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1answer
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 ...
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3answers
3k views

Changing frequency on RF Link

I am using these RF link modules for a project since I need a cheap, small, and simple wireless link between two microcontrollers. The data being sent is a single integer and can be spam sent to ...