And just to keep things straight...
SWR doesn't change with power, it stays the same. The accuracy of the meter doing the SWR checking can certainly vary according to calibration and the general design of that meter.
SWR is a -ratio- of the forward power and the reverse power. If the feed line and antenna hasn't been changed, then that ratio isn't going to be changed either, so the SWR doesn't change.
If/when that power level get's to the point where it's approaching the limit of the meter, the feed line, or the antenna, meaning that any of those things start to be 'stressed' to the point where they change their characteristics, then sure, that SWR can start changing. If you are very lucky, you'll catch/see that change and stop it before something is permanently changed ('dies', pops, burns up, whatever).
Those limits are different for all those things, is typically at a higher level than most people will get to, so shouldn't cause worry for small changes. 'Large' changes? Yeah, I think I'd find out why there's a change like that. And naturally, the whole mess depends on how well the entire antenna system is impedance matched and the antenna resonant.
- 'Doc
SWR doesn't change with power, it stays the same. The accuracy of the meter doing the SWR checking can certainly vary according to calibration and the general design of that meter.
SWR is a -ratio- of the forward power and the reverse power. If the feed line and antenna hasn't been changed, then that ratio isn't going to be changed either, so the SWR doesn't change.
If/when that power level get's to the point where it's approaching the limit of the meter, the feed line, or the antenna, meaning that any of those things start to be 'stressed' to the point where they change their characteristics, then sure, that SWR can start changing. If you are very lucky, you'll catch/see that change and stop it before something is permanently changed ('dies', pops, burns up, whatever).
Those limits are different for all those things, is typically at a higher level than most people will get to, so shouldn't cause worry for small changes. 'Large' changes? Yeah, I think I'd find out why there's a change like that. And naturally, the whole mess depends on how well the entire antenna system is impedance matched and the antenna resonant.
- 'Doc
