Scopes tend to have non-flat frequency response. I'd consider a precision load and something like an HP 3400A True RMS meter for up to a hunderd MHz or so.
Above 10 MHz the HP 432A would be my choice. FWIW, -John =============== > At 11:41 PM 11/30/2009, Joseph Gray wrote... >>We all have our various highly accurate frequency and perhaps time >>references. Is there a relatively simple and inexpensive method of >>making an accurate RF power level reference? >>Joe Gray >>KA5ZEC > > Since you're a ham, I'll assume you're primarily concerned with the > simple case (50 ohm source impedance, sine wave, HF-VHF). Use an > o-scope to measure the p-p voltage across a precision 50 ohm load (I > use the Caddock thick film resistors available through Digikey, which > are 1%, with minimal inductance). > > The power is then W=((Vpp/2)^2)/100 > > Not time-nuts precision, but good "bang for the buck," and you can get > better accuracy than a Bird wattmeter (which is only 5%), assuming you > have a decent scope. Without an o-scope, you can make a peak detector > and use a voltmeter, with some loss of low level accuracy. > > You asked for "simple and inexpensive." For higher frequencies, > different impedances, non-sine waves, the other more expensive > solutions are needed. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
