Re: LF: 137.5kHz WSPR Tuesday evening - reports appreciated

[Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>]

Hi Chris,

Yes, right. But my _expression_ is the same. 0,707 = 1/sqrt(2), so U^2/R = P =(û/sqrt(2))^2/R =û^2/2/R =û^2/2*R. Measuring 100 Vp at 50 Ohm is 100 W :-)

73, Stefan


Am 09.09.2010 10:11, schrieb Chris:

Hi Stefan,

I thought the power was the RMS voltage squared (i.e. peak voltage X 0.707) divided by the resistance.

Chris, G4AYT.

----- Original Message -----

From: Stefan Schäfer

To: rsgb_lf_group@blacksheep.org

Sent: Tuesday, September 07, 2010 9:31 PM

Subject: Re: LF: 137.5kHz WSPR Tuesday evening - reports appreciated

Roger,

For measuring the output power take a 50 Ohm dummy load (50, not 55 Ohms or so) and measure the peak voltage with an oscilloscope. Type this into the excel file and calculate the output power (P=(û)^2/(2*R)).

73, Stefan