transmitter

  1. C

    Need help with FM Radio Transmitter / Amplifier

    So I purchased this : (HanRongDa HDR-831) HanRongDa HDR-831 It's working great but the practical range is about 15 meters. I'm looking to upgrade this. The thing is, I know very little about radio frequencies and antennas. Can something like this work ? Ebay Amplifier The device I purchased...
  2. serhiip

    How to send sensor signal to 5-10km?

    Now I detect motion with my Arduino Nano and 3pin motion detector: When detector triggers, I need to send signal (distance at least 5km) to another Arduino Nano and catch it. As far as I understand, 433Mhz is the optimal frequency for this. Please suggest me what should I use? Which circuit...
  3. reyfonal21

    How you know to choose BJT transistor or MOSFET for you Tesla Coil circuit

    Hello, people! Thanks for the dropping. I made a Tesla Coil with oscillator circuit on it for project in school and it work well. But I want know how to choose ideal BJT/MOSFET transistor for the transmitter. Is there any reason, formula, or theory that I should know? Because Youtube and other...
  4. A

    Looking for some help to build an RF Modulator schematic from 1985 I found online :)

    Hey all, I am looking for some help to build an RF Modulator schematic from 1985. I was searching for a way to wirelessly transmit a UHF/VHF TV signal to an old portable TV I have and found a schematic on a website called Petlibrary (https://petlibrary.tripod.com/rfmod.htm). My idea was to use...
  5. K

    Battery choice for wildlife VHF transmitter refurb

    Hi All, This is my first post at AAC; it looks like a great place to come for advice about battery selection for my project. I'm trying to refurbish some wildlife radio transmitters. The manufacturer wants $165 to refurbish each one, when all they need is a new battery. I've not been able to...
  6. jpf88

    proximity sensor up to 200metres for outdoor application

    Hi, I have a project that i would like to complete. i need to activate an LED light outdoors, whenever a designated vehicle comes within 200-300metres of the LED light. i was thinking of using a simple 12v FM radio transmitter on the vehicle. the LED would have an FM radio reciever tuned to...
  7. C

    How do PKE keyless remotes work (inductive data transmission) and how would I "hack" one to make a transceiver?

    I'm wanting an undersea short-range remote (wireless button for dive thrusters) and induction seems perfect, so I bought a passive keyless car alarm to see how they work. I do understand that the car transmits an inductive signal, which the remote picks up (and then the remote does it's own...
  8. Denis Molodtsov

    Can you spot a transmitter in this device? Can I add an antenna to this device?

    I have puchaed a wireless Bike Alarm and wanted to figure out how to extend its range. I want to try to extend its reach to 50 meters from the default 20 meters. There is wireless "fob" (KS-WL09C) that I disassembled. The photo is available below. Question: Can someone, please, spot a...
  9. G

    Questions about a design for transmitting and receiving a pulse over 100 meters or less (Measure distance to within 1 mm)

    Note: I've dabbled in electronics for many years, but I'm a newb when it comes to radio circuitry, so please forgive me for anything dumb I may say/ask. I'm trying to design a system where I can send a single radio pulse (no complex information, just a single pulse) periodically. This pulse...
  10. Enrique Garcia Mainieri

    Low Voltage Signal T/R switch

    Hello Forum, I am designing an Ultrasonic Reciever and Transmitter circuit, in which the Reciever and Transmitter Transducers are connected with the same cables. That means that the Excitation signal and the Received signal will be transported by the same medium. The Excitation signal is a...
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