Measuring ultra-low output power is not easy

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Measuring ultra-low output power is not easy

Be careful before claiming DX using very low power levels.

To transmit 100 microwatts, you could arrange for the RF output stage to be supplied just 100 microwatts of power. It is difficult to design a circuit to function with so little power applied, unless your job is to design electronic watches. I don't know of any commercial rigs that can be dialed down to 100 microwatts.

Another approach is to attenuate the output of a low-powered rig. For example, my IC-703 can make 10 watts. If I dial that down to 1 watt, then place a 30 dB attenuator in the antenna feedline, you might assume that 1 milliwatt is now being radiated.

There could easily be more than a milliwatt of stray RF leaving via the mike cord, power cord or computer interface cable. An installation might even be radiating from the unshielded ground wire which connects the rig's body to the earth. We've all heard stories about the problems getting a good RF ground on the second floor of a building.

How to actually radiate 100 microwatts? That would be a good research article for an amateur magazine. Persons claiming such low radiated power levels are encouraged to share their methods.