Home |
Search |
Today's Posts |
#2
![]() |
|||
|
|||
![]()
In rec.radio.amateur.antenna gareth wrote:
Taking one's cue from the Alford Slot Antenna, let us propose the use of the fields in the air gap of a parallel plate capacitor as the source of RF radiation. Slot antennas get added to the list of things Gareth doesn't understand. A parallel plate capacitor is nothing like a slot antenna of any kind and does not radiate like an antenna. To do this, we will terminate our 50 ohm coax Slot antennas are fed with waveguide. with a series LC circuit of 50 ohm resistive impedances (so one will be 25+jX and the other 25-jX) at the operating frequency. That would be two 25 Ohm resistors, one of which is slightly capacitive and the other slightly inductive. Very little of the energy supplied to our antenna will be radiated, This part is correct; it will mostly be heat dissipated in the two 25 Ohm resistors in series. and most will be stored as energy in the resonant LC circuit, Nope, dissipated as heat in the resistors. until such time as the stored energy outdoes the incoming energy,and the LC circuit will now act as an energy source, sending it back down the coax. Series LC circuits get added to the list of things Gareth doesn't understand. So, we'll have a short antenna, matched to its feeder, that is not radiating all the power fed to it, and is returning some of that power back down the coax. Gibberish. (An even simpler case, although it would give a reactiv match, would be the capacitor alone, but think for one minute, why do you get the 90 degrees phase relationship between the volts and current in a capacitor? Because it acts like an energy source in its own right! For a quarter cycle for AC. Capacitors get added to the list of things Gareth doesn't understand. -- Jim Pennino |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Short antenna = reduced power | Antenna | |||
ANTENNA TWINLEAD FEEDER | Antenna | |||
Emergency power source | Equipment | |||
Source for power transformer | Homebrew | |||
Another source for $9.95 Bell & Howell Short wave radio | Shortwave |