Calibration readings for a germanium diode 4.7M resistor .01 cap RF probe
like the one at http://www.io.com/~n5fc/rfprobe2.htm
If you compare the observed voltage readings at low power levels to the expected readings given at
http://www.minicircuits.com/pages/pdfs/dg03-110.pdf
you can see significant departures below 100mW
or below RF probe observed voltages of about 2.0 volts.
Calibration was done with a K2,a switchable attenuator, a 50 ohm load and
a W7ZOI/W7PUA AD8307 power meter with 40 dB tap.
KL7R Jan 2007
| Power Meter Reading (dBm) | Power (Watts) | RF Probe Reading (Volts) |
| -20 | 10u | 0.002 |
| -10 | 100u | 0.013 |
| -6 | .25m | 0.030 |
| -3 | .5m | 0.051 |
| 0 | 1m | 0.100 |
| 7 | 5m | 0.270 |
| 8 | 6.4m | 0.350 |
| 11 | 12.5m | 0.560 |
| 14 | 25m | 0.930 |
| 17 | 50m | 1.350 |
| 20 | 100m | 2.200 |
| 26 | 0.4 | 4.500 |
| 27 | 0.5 | 5.000 |
| 30 | 1.0 | 8.000 |
| 32 | 1.6 | 10.400 |
| 33 | 2.0 | 11.000 |
| 34 | 2.5 | 12.750 |
| 36 | 4.0 | 14.500 |
| 37 | 5.0 | 16.250 |
| 38 | 6.4 | 18.900 |
| 39 | 8.0 | 20.300 |
| 40 | 10.0 | 22.500 |