Re: Measuring SSB RMS Power

Posted by Don Wilhelm on Jun 20, 2019; 3:10pm
URL: http://elecraft.85.s1.nabble.com/Measuring-SSB-RMS-Power-tp7653233p7653237.html

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 <[hidden email]> 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 <[hidden email]> 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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