Ken,

The DL1 is a 50 ohm load. I did specify that the formula was applicable for a 50 ohm load.

For other loads, the formula is Vpeak squared divided by 8R.

It saves the trouble of converting to RMS and then using the more familiar Vrms squared divided by R.

If you wish to derive the formula yourself, you can do that, but represent the RMS voltage as V time sqrt 2 rather then the approximation of 1.414 (or 0.707) which is normally shown. The sqrt will cancel out when it is squared.

73,
Don W3FPR

On 6/20/2019 10:50 AM, Ken Roberson via Elecraft wrote:
  Don , That may be peak to peak voltage squared decided by 400 for a 50 ohm 
load.
Thanks 73 Ken K5DNL

     On Thursday, June 20, 2019, 9:30:46 AM CDT, Bob McGraw K4TAX 
<[email protected]> wrote:
Here is a paper on the topic. This covers the correct procedure.

http://www.eng.auburn.edu/~troppel/courses/TIMS-manuals-r5/TIMS%20Experiment%20Manuals/Student_Text/Vol-A1/a1-12.pdf

73
Bob, K4TAX


Sent from my iPhone

On Jun 20, 2019, at 8:38 AM, John Oppenheimer <[email protected]> wrote:

Using DL1 with Oscilloscope to measure KX3 SSB RMS power:

https://www.kn5l.net/ssbpower/

Question, is this technique correct?

John KN5L
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