Home |
Search |
Today's Posts |
|
#1
|
|||
|
|||
It might be of interest to note that old time video amplifiers with peaking
coils sometimes caused ghosts on the screen that were indistinguishable from ghosts caused by reflections. Tam/WB2TT "Ian White, G3SEK" wrote in message ... W5DXP wrote: Think what would have happened if you had measured the impedance at the TX end of your o/c transmission line (very high or very low, depending on the length) and replaced it with a resistor and inductor/capacitor giving the same value of R +/- jX. There's no transmission line, so no traveling waves of anything, and no reflections - just a transmitter with a very wrong value of load impedance. The 1625s would have burned up just the same. Yes they would, but in that case reflections are not the cause of the impedance. Good... hold that thought. In the first case, reflections are the *CAUSE* of the impedance that burned up the transmitter. Correct; and the values of R and +/-jX that the transmitter sees are calculated by considering the reflected voltage and current waves. So now we have two cases, one where reflections happen and one where they can't. The transmitter suffers exactly the same problem in both cases, entirely because it sees the same wrong value of wrong load impedance. "Reflected power" simply doesn't enter into it. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Conservation of Energy | Antenna |