I measure the peak to peak value using my scope. Then power equals E
squared divided by R. This is good enough for "government work".
Looking at it another way:
100 watts across 50.0 ohms produces 70.710 volts and a current of 1.4142
amps.
1500 watts across 50.0 ohm produces 273.8613 volts and a current of 5.477
amps.
Another approach, I have a known good RF amp meter that I use with my dummy
loads. Comes in handy.
Again, This is good enough for "government work".
73
Bob, K4TAX
----- Original Message -----
From: "Williams Barry" <Bnwilliams@varco.com>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Wednesday, June 08, 2005 9:15 AM
Subject: [TenTec] Voltages on 50 ohm Dummy Load
Hello All,
I need to calibrate the watt meters on my Titan, Omni VI+ and 253 Tuner.
I have a Drake 2 kw PEP dummy load and a nice 200 mHz storage scope. In
order to measure output, should I measure RMS, or Peak voltage, (if I
use a sine wave input), and what are the voltages for 100 watts and the
legal limit?
My guess for a sine wave would be that for 1500 watts PEP out, I should
see a peak voltage of about 274 volts, and 70 volts for 100 watts, if
the dummy load is truly 50 ohms. Is this correct?
Thanks,
Barry
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