[Milsurplus] A Ham Radio Math Quiz

[J. Forster]

Let me guess. You calculate that you are getting far too much power?

Your P-P to RMS calculation is off. 1 / 1.414 = 0.7 is Peak to RMS. You
have to divide by 2 * SQR (2) = 1 / 2.828, so the RMS voltage the scope is
seeing is about 35.36 VRMS.

-John

================



>
> ----- Original Message -----
> From: "Peter Gottlieb" <nerd at verizon.net>
>
>> What's the intent and application of this?
>
> I'm working with a 1930s MOPA transmitter,
> which is speced to deliver about 3 watts out.
> 100 pFd in series with 5 Ohms is the "phantom antenna"
> designed for it.   Scope says 100 Volts PtP or about
> 70 Volts RMS across the load at 3870 KC.
> Z of the load should be about 411 Ohms.
> I know the output is low and I'm not finished looking
> for the cause, but I don't believe the solutions I'm
> getting, so I'd like to see how the many people
> smarter than me solve this problem, so I can
> find my errors.
>
> Thanks,
> Dave S.
>
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