Posted: 1/4/2016 11:48:15 PM EDT
| Is there an affordable way to measure RF power at microwave freqs? |
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Quoted:
Terminate into a resistive load, measure temp increase. Connect adjustable DC power supply to same load, match the increase and P = I * E. Quoted:
Quoted:
Is there an affordable way to measure RF power at microwave freqs? Terminate into a resistive load, measure temp increase. Connect adjustable DC power supply to same load, match the increase and P = I * E. Pretty much. You can do some fancy adjustable attenuators into a directional coupler into a resistive load, and measure the directional power each way, as long as your o-scope can measure the frequency. But then you're outside of the "affordable" constraint. |
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Quoted:
Terminate into a resistive load, measure temp increase. Connect adjustable DC power supply to same load, match the increase and P = I * E. Quoted:
Quoted:
Is there an affordable way to measure RF power at microwave freqs? Terminate into a resistive load, measure temp increase. Connect adjustable DC power supply to same load, match the increase and P = I * E. That won't work unless you account for time. Energy in heat is measured through Joules. Watts is Joules/second. So you reach the same temperature at 10W as 100W...just takes a time factor of 10 less or more either way. Add heat transfer and things will get real weird. Easier way is to measure the difference in temperature after a set amount of time (straight RF to the load), and then assume your load is built of a single material (mostly) and use the specific heat and mass of the object to solve for enthalpy (heat)...then divide that by the time to get Watts. e = m*Cp*?T P = e/t So say you have an aluminum dummy load that comes it at .25 kg. Cp of aluminium is .91 kJ/kg K if memory serves correctly (my Thermo tables are not currently in front of me). You measure change of temperature of 20 degrees (C) after 20 seconds. That's 455 J of heat which works out to 22.75 W. |
Yeah I more so just looking for something like a bird watt meter that can go to 3Ghz 
Most of the gear will need to be tested in the field and not on a lab bench so there is that too. When I said affordable I meant "microwave affordable" not "ham affordable" haha. |