I'm not ready for "power nuts" yet, but thanks to all for the suggestions. I was considering the o'scope method, but thought I'd see what others had to say. It's always interesting to see how different people tackle a problem.
Joe Gray KA5ZEC On Tue, Dec 1, 2009 at 5:00 PM, J. Forster <[email protected]> wrote: > 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. > > _______________________________________________ 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.
