G0MJW wrote:
>> That's a very important point. No amateur "power" meter actually
>> MEASURES RF power.
>
>Not strictly true. There are some amateur meters that measure power directly
>by absorbing it in a load. I think SSB produce one and there are several
>home made designs.
>
The test is whether the instrument can be calibrated directly from other
non-RF physical standards. If so, it's a true measurement of RF power.
If it needs another RF wattmeter or voltmeter for calibration, then it
isn't an absolute measurement.
Many instruments use heat sensors such as thermistors/thermocouples/
bolometers to detect RF, but cannot be calibrated by non-RF means.
On the other hand, some instruments do measure RF power by substituting
DC power, to achieve the same heating effect. I guess those count as
true measurements.
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.demon.co.uk/g3sek
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