Thread: SWR - wtf?
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Old June 29th 05, 07:13 PM
Roy Lewallen
 
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Buck wrote:

I believe he is right. Radios drop power when they don't like the SWR
and raise it when it does.


This is an illustration of a common problem. It's really improper
*impedances* presented to the radio that disturb it; it doesn't know or
care about the actual SWR on whatever transmission line may or may not
be connected. Transmitters typically specify and show this load
impedance as "SWR". But they can't tell the difference between a half
wavelength 50 ohm line with 100 ohm load, which has a line SWR of 2:1;
any length of 100 ohm line with a 100 ohm load, which has a line SWR of
1:1; a quarter wavelength of 300 ohm line with a 900 ohm load, which has
a line SWR of 3:1; or a 100 ohm resistor. All these and an infinite
number of other combinations will present 100 ohms to the rig, all will
cause the rig's SWR meter to read 2:1, and all will have exactly the
same effect.

Roy Lewallen, W7EL