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Re: Experimental Help - Terry?
Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> The hot wire sensor is one commom way to measure RF power. I have some
> literature on it. I'll try to dig it up.
> > Might be a 'hot wire' (second gen) type sensor.
I'd say that a thermal detector is THE way that RF power is measured
(accurately)... Whether a bolometer or thermistor... The fancy detectors use
balanced circuits that hold the detector at constant temperature with a DC
current. The amount the DC current decreases (and the resistance..) tells
you how much power is being dumped into with the RF. Uncertainties in this
sort of sensor are:
1) How accurately you measure the DC current
2) How accurately you hold temperature (this one's easy, because it's
basically a nulling to hold it at a zero, rather than actually measuring
3) RF mismatch.. The RF power has to really get into the load, and not get
reflected back. The connectors are a problem here..
But, in any case, all those HP power meters use thermistor heads...