Enhancing the Ramsey AM-25

Build an AM radio transmitter Did you know that on the AM band you can broadcast over power lines in your neighborhood? You can’t do that on the fashionable FM band, which is 100 times higher in frequency. The AM-25 is a commercial Ramsey kit selling for under...

Vacuum Tube Turns 100

Vacuum Tube in 100th Year Same Old Challenges But what is a cold-cathode multipactor? (Nuts & Volts, November, 2006) The engineering challenges of the hot-cathode vacuum tube are the same today as when it was invented back in 1906: cathode heat, demanding power...