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I have just had several glasses of Australian Zonte's Footstep wine.
I can recommend it. Its name can be traced back to a marsupial which replaced the dinosaurs. Transmission lines, which even the dinosaurs knew nothing about, are associated with losses of one sort and another. But there is one sort of loss which is never mentioned in discussions on this newsgroup. It is reflection loss. Reflection loss is sometimes known as mismatch loss. It is that loss which occurs in the load impedance because it is not matched to the line impedance Zo. When the line is not matched there is a reflection of amps and volts back towards the generator. The reflected volts and amps, in conjunction with the existing volts and amps, present to the generator an impedance which causes it to deliver to the line exactly the power in the load plus the power lost in the line. That this occurs is quite obvious. When calculated, the power lost in the line automatically takes into account the increase in loss due to SWR which occurs on the line due to the mismatch of the load. But the most important parameter is not the SWR but the reflection coefficient, Gamma. Gamma = ( Zt - Zo ) / ( Zt + Zo ). The loss in the load due to reflection is given by Reflection Loss = 4.343 * Ln( 1 - Square( G ) ) decibels. where G is the magnitude of the reflection coefficient which is easy to measure. ---- Reg. |
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