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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0
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1answer
26 views

Need a help with 3D Low Frequency Wakeup Receiver AS3933

I am software developer and I am totally new to circuits field. Can somebody help me to understand how the 125 kHz transmitter and AS3933 receiver works? This is the link where it says how it ...
0
votes
0answers
76 views

How to switch a transistor when a radio signal is received?

I have a circuit which switches on by sending current to the base of one of its transistors. I'm trying to make receiver which can receive signals from a AM transmitter and send current to base of ...
0
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0answers
25 views

Can we capture and reproduce the bluetooth signals

Are there any devices that can capture bluetooth signals and reproduce them? Or is it simply possible to capture bluetooth signals if we have any bluetooth device? Does a bluetooth device have ...
-1
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1answer
114 views

Trying to figure out the distance my computer is from my Bluetooth peripheral via RSSI. Is it possible?

I'm having a great deal of trouble figuring it out. I know it's far from exact, but I would like to have a reasonable estimate in meters. Right now my device is reporting back to my the RSSI value ...
0
votes
1answer
100 views

Power LED's using RF transmitter and receiver with Arduino

I'm working on a project that I have two sensors, two Arduinos (a YUN and an UNO), two LED's, and an RF transmitter/receiver It's a pretty simple procedure: Activate a force sensor, send it via RF ...
0
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1answer
220 views

FM transmitter main output frequency

please tell me the output frequency of this circuit,its work and has about 10 watt power with using C2101 as output stage,thanks It's working,and has high power in so far as I turn it on close to ...
2
votes
1answer
152 views

Amplifying the signal from a transponder detection loop

Transponder I have a simple powered transponder which sends data using binary phase-shift keying (BPSK) on a 5Mhz carrier with a required range of 6-12 inches. It is used to time laps of remote ...
2
votes
1answer
87 views

How does a cube sat communicate with ground station with a 1w antenna

I heard that cubesat signals can be received with a hand held radio. Its confusing me that how a 1 metre antenna radiating 1watt energy can simply be received using hand held radios. I am designing a ...
1
vote
1answer
57 views

Can I estimate Wi-Fi's power transmission in function of the amount of data transmitted?

For a specific device connected to specific AP. Can I estimate the differences in radiation power (mWh) depending on the data transmitted (2KB/s vs 200KB/s)? If so, how?
1
vote
2answers
137 views

Hardware advice for simple wireless embedded application

Now, I am going to learn embedded programming in microcontroller. I am going to create a device that will receive signal from wireless transmitter. The range will be less than 30 meters. So, I have ...
3
votes
1answer
954 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. ...
2
votes
0answers
54 views

Bluetooth receiver from multiple transmitters

I need a bluetooth receiver to receive a signal from few transmitters. There is extremely little information about bluetooth on the internet. Google gives a lot of topics about android and iPhones, ...
0
votes
3answers
79 views

Linear potentiometer for suspension travel

I am working on a project for university measuring the extension of a cars suspension. I have a potentiometer available to me, but have a few questions regarding how to use it. I understand that it ...
1
vote
1answer
78 views

Using RF Link Transmitter/Receiver - ADC vs Microcontroller?

I have a sensor that gives off 4 volts when actuated and I would like to transmit it a distance to a light. So I found these RF Link Transmitter/Receiver at 434MHz: ...
0
votes
2answers
64 views

How to increase frequency modulation index?

I'm thinking of making a low power FM transmitter. Here's a diagram. It seems an absolute pull range of a VCXO will limit the modulation index. Is there possibly a way to extend it?
3
votes
3answers
478 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 ...
0
votes
1answer
62 views

Can a smartphone transmit over the 902-928MHz bands? [closed]

I came across a remote control that uses the 902-928MHz band. Can a smartphone transmit WiFi/Bluetooth over those frequencies? If yes, is there anything special about it? Thanks
3
votes
2answers
122 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 ...
1
vote
2answers
1k views

Is it possible to use 2-way walkie talkie to locate position?

Basically, given no GPS is allowed, can we use walkie talkie to locate the position of a car / a person? I am assuming the walkie talkie is using radio, not GPS-based. What equipments will be ...
1
vote
2answers
112 views

Why is it so hard to get waves through the earth and ocean?

Quoted from the source Crystal sets to Sideband, the author said if you have an ohm meter measuring across the whole earth, the meter would display only 300 ohms. A while ago, I asked about earth ...
0
votes
1answer
223 views

UHF Transmitter - Arduino - How to

I am planning to do a near space balloon project with my son. I want to do something special. I don't want to just send up a camera I want to broadcast live video and other metrics. I have a strong ...
8
votes
6answers
8k views

ultra low power mini wireless transmitter / receiver?

I'm looking for suggestions for a wireless transmitter & receiver combination. I'm basically just trying to bridge several buttons over a wireless signal(s) (i.e. send a 1 bit signal) in as small ...
2
votes
1answer
90 views

How to debug a transmitting configuration?

I'm using a CC1101 radio to communicate with an existing protocol. The settings I've used to configure the radio seem sound, as I'm able to receive messages from the 'other end' without errors. My ...
0
votes
1answer
259 views

Using 27MHz car with 49MHz remote control

I managed to do something like this guy here, but after I connected the Arduino to the 49MHz remote control, I figured out that I have another car which works on ...
2
votes
2answers
68 views

Wireless signal reflection

When two devices are connected via wireless, one device sends a character using its TX line, and the character is received by the other device on its RX line, and vice versa. My question is, RF ...
1
vote
2answers
107 views

Re-broadcasting a wideband satellite television signal over a short distance?

Normally a coax cable connects a satellite dish to the receiver. I'm in a situation where I can't easily install a coax cable, but a wireless signal ought to be possible because it's only 10 meters ...
4
votes
1answer
171 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?
4
votes
2answers
717 views

Wireless transmission/reception through 100 feet (30m), including concrete wall

I have an electrical engineering degree, but little experience in building wireless equipment. I need to transmit a signal through about 100 feet of distance, including a concrete wall. I need ...
1
vote
2answers
635 views

Using one RF transmitter to send an On/Off signal to multiple receivers

I want to create a system where I can send an On/Off signal to multiple receivers, to say, tell them to turn on an LED. Would I need to have a transmitter/receiver pair for each LED, or can I just ...
0
votes
1answer
39 views

Calculate transmitting power of the Transmitter

I cannot get a hold of my professor and I'm stuck tyring to understand how to solve this problem. It's not homework or an assignment I'm preparing my self for a test. So as the title states I need ...
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2answers
422 views
1
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2answers
721 views

Any wireless technology to find the distance between transmitter and receiver

I have a static transmitter and a mobile receiver. Is there any wireless technology to find the distance between the two in real time. Apart from using gps!
0
votes
1answer
88 views

GPS SOS Signal Device

Is there a way to send GPS coordinates from one device to another, without the use of any kind of cell service? What I'm attempting to design is a device that connect to a motorcycles' tip-over ...
2
votes
3answers
139 views

High Powered Radio Transmitters

What kind of radio transmitter would be used on an data collection unit to transmit telemetry over long distances? For example a weather station in a remote location, or in a buoy just off the coast ...
3
votes
3answers
335 views

Does an RF receiver constantly consume power?

I'm building a battery operated robotic arm and would like to use a cheap, short distance RF transmitter/receiver kit to trigger it. However I would like to know whether the receiver will constantly ...
3
votes
2answers
125 views

Designing a Morse code transmit/receive shoe

Thank you for considering my general question, which I assure you is serious! I want to build -- or have built -- a magnificent shoe that can convert taps (front of the shoe) into Morse code and ...
-4
votes
1answer
90 views

Mapping Temperature Transmitter Range: 4-20 mA to temperature Range: 0-100C [closed]

I want to know as to how do you subdivide the above range 0 C To 100 C into 4 to 20 mA.? Each mA will be of what Range in degree C.
-1
votes
1answer
190 views

Question about transmitter/reciever

I have built a transmitter/receiver with an antenna and crystal. I am wondering if it is stable. Here is my transmitter: simulate this circuit – Schematic created using CircuitLab Here ...
-5
votes
2answers
456 views

How to make a Transmitter/Receiver [closed]

I am trying to make a transmitter and a receiver, I have two crystals and two antennas (basically a straight piece of metal with plastic covering), how could I make a transmitter and receiver with ...
0
votes
2answers
143 views

Checksum done without microcontroller

How could I transmit data from a device such as a distance sensor or quadrature encoder with an RF transmitter and also transmit a checksum or will I have to use a microcontroller such as the Arduino? ...
2
votes
2answers
543 views

Is there any circuit like “Burglar alarm ” or “Proximity dector” with a range of 100 meters

I am in search of a circuit which works with IR or RF wave with a range of 100 meter to detect proximity or burglar. I need this to detect the presence of human or animals One thing important is i ...
3
votes
1answer
217 views

How do I determine the proper FM transmitter strength?

I want to build an FM transmitter that will transmit (on an unused frequency) from my laptop (near my video projector) to my receiver (about 20' away on the other side of the room). Then, I thought ...
3
votes
1answer
487 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 ...
5
votes
4answers
173 views

Digital Compass identifying direction of travel for use with trains

I work in a control center for a train company in the UK. Our trains work in either direction but only one end has first class carriages. Because trains on our network reverse quite a lot it is ...
1
vote
1answer
131 views

Spark Transmitter with flyback driver and good arcs

I recently built a Fly-back Driver with a fly-back transformer and a primary voltage input of 12 volts and the arcs are about an inch long ( i don't know the exact output voltage because I don't have ...
0
votes
2answers
559 views

Transmitting GPS data to Raspberry Pi

I am trying to figure out a way to get GPS data from a remote source to a Raspberry Pi. The remote source would be a helmet mounted GPS receiver so it would need to be small and preferably ...
0
votes
1answer
165 views

What kind of Transmitter and receiver would I need? [closed]

I am trying to figure out exactly what it is I am needing, I am wanting to protect my chickens from my dog killing them! I want to place a small transmitter onto a leg band which will be placed ...
0
votes
1answer
308 views

How to make a cw transmitter with a crystal oscillator (A0645147)?

I am trying to make a very basic cw transmitter, so far i got a 5V crystal oscillator: A0645147. Whenever I apply voltage to it i can pick up the signal on my handheld however i am not hearing the ...
1
vote
1answer
76 views

Power and decibels

In one of the examples in a engineering textbook, I noticed that the decibel value for the Power of a transmitter (also known as modulator) was 20DB and this was said to be equivalent to 100W. ...
1
vote
1answer
1k views

How to measure distance from moving object using RFID?

I want to make a project on an anti-collision system using RFID. I'm facing many problems selecting RF reader and tag: the required UHF generator, tags and reader are expensive. Any suggestions on ...