1. M

    Wireless energy transfer

    If you build a long range wireless energy transfer device, why can't you use a lower frequency than the microwave range to transfer energy? Why does it have to be microwaves? Why not say 10 megahertz?
  2. A

    Type 807 Tube RF amplifier with transistor a pre amp

    Hi all, I have a 807 vacuum tube and I want to make a CW RF amplifier with it. I am thinking of using transistors in pre amplifier and 807 as final power amp. I have only one tube so I cannot make push pull amp. First of all I need to know if it will be possible to make such RF amplifier. If...
  3. AttacK

    LW/MW and FM antenna suggestion for old car radio (25 years old)

    First of all, i want to listen in my house, you can forget a car. It has been in the warehouse for a long time. Yesterday i tried it. Although I haven't connected an antenna yet, it still works. Because of it has 10-12 cm antenna plug cable probably. As it stands, FM is listened almost...
  4. V

    Change frequency of PCB

    Hi, I have some speakers I love, they have a PCB RF reciever inside. I bought more speakers but they are a different frequency.. I'd like to change them so they all match but have no idea what I am doing. Can you help?
  5. 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...
  6. A

    Identification of components in old radio

    Hi. I have recently gotten my hands on what I think is a very old radio: I am interested in how this device works. Inside the case is, among other things, a black cylinder containing some circuitry and on its side is a schematic: I have tried making a hand drawn copy: I am having a hard time...
  7. A

    Documenting a TRF Radio build

    Greetings, I'm new to electronics and am interested in the field just as a hobbyist. I've read the Complete electronics self teaching guide by Boysen and Kybett and am now moving to Basic Antennas ARRL and Building your own transistor radios by R. Quan. To be honest im attracted to RF...
  8. G

    RF Amplifier Query

    Hi everyone I have a RF Long wave transmitter (broadcasts only to 10ft diamater). However there are no rf amplifier products available on the market to purchase. Does anyone know where I can get schematics to build one? (I know what transformers, diodes, transistors, capacitors, and resistors...
  9. macsaba

    Car radio with external bluetooth module only mono

    Hi! I have a 6006E CD RDS EON car radio and I build Bluetooth function into it. There are two 0R resistors in the wires from the radio module to the mixer module (it mixes the signal from the radio receiver and CD player and does a lot of stuff, which I don't know about). I removed these...
  10. I

    Master thesis question

    Hey guys! I’m a EEE student and will be a finalist next year! I need to chose a project for my master thesis and I’m sort of unsure. I’ve always loved wireless/RF communications, specially microwave systems, but I am unsure about what to do for my thesis. I shortlisted 3 main things: -Anti...