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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51 views

PIC16C54 used as signal generator from 100 KHz to 180 MHz

I have a PIC16C54 used as a DDS which generates 100 KHz to 180 MHz sine waves, model #80-035 datakit , I need source code but company is out of business. I purchased this as the early model called ...
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1answer
49 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 ...
1
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1answer
85 views

How do I sniff this RF Transmitter Gate Opener Circuit?

What piece of hardware am I looking for to observe the transmitted radio signal? Would an oscilloscope come in handy here? is this a 2-channel RF remote, a 3channel RF remote, or something else? My ...
1
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4answers
91 views

How do multiple transmitters and single reciever work?

I have multiple digital transmitters sending packets to an receiver, and packets from different transmitters may arrive at the same time, how can the receiver differentiate multiple packets at the ...
1
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0answers
290 views

Audio + Video Transmitter + Reciever With 5 - 10 KM Range Circuit Diagram [closed]

I'm looking for a circuit diagram for a audio (doesn't have to be stereo) with video transmitter and reciever that has a range of more that 5 kilometers. I don't really have any limits on power ...
1
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3answers
112 views

Radio frequency signal transmitter

I lost the remote of an RC helicopter. I want to make a remote and know about the circuit. I am searching for this component which has three legs beside the LED in the pic. Would someone help me ...
1
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1answer
121 views

How to find out what radio frequency is being emitted?

Let's say I have something akin to a garage door clicker. How can I discover the frequency and message it sends with no other information on the device? I want to decode this to the electrical ...
0
votes
1answer
87 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 ...
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0answers
109 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 ...
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1answer
60 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 ...
0
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1answer
408 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 ...
2
votes
1answer
157 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
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1answer
72 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?
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2answers
155 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 ...
1
vote
0answers
77 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
131 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
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1answer
170 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: ...
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votes
1answer
342 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 ...
0
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2answers
85 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?
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1answer
159 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
72 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
137 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
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2answers
113 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
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1answer
290 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 ...
0
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1answer
367 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
77 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 ...
2
votes
1answer
109 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 ...
2
votes
1answer
232 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 ...
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2answers
127 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
276 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?
0
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1answer
41 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
997 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 ...
1
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2answers
1k 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
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1answer
113 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 ...
3
votes
3answers
425 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
128 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
112 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.
2
votes
3answers
143 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 ...
-1
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1answer
229 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 ...
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votes
2answers
525 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
147 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
660 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
268 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 ...
5
votes
4answers
182 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 ...
3
votes
1answer
541 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 ...
1
vote
1answer
137 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
594 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
175 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
346 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
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1answer
80 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. ...