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DL-QRP-AG thermal power meter, 20 dB/10Watt attenuator, dummy load all in one

The special features of the thermal wattmeter QRP  are its
ease of construction, its low price, easy calibration and its short
response time. Very accurate power measurements are possible with
this wattmeter, even minor errors can be detected when constructing PAs.
Without measuring technique, even small errors can sum up and the fun
of constructing your own equipment is replaced by frustration.

The measurement is done with a miniature lamp coupled to a photo-diode.
The SP126 (P104) are housed in a black opaque plastic case. If You
intend to use a diode with clear case, the slope of the display will
be different. Calibration is done applying a DC voltage to the input.
The calibration data can be glued to the case of the wattmeter.

Experimenting gets even easier, if you use the pcb LAA98 (power meter,
dummy load and attenuator). In that version an ultra-micro lamp coupled
to a BPW34FS infrared detector  is used. The 20dB attenuator is usable up to 500MHz.

The usefulness of the wattmeter above 52MHz could not be tested, however,
due to lack of suitable test equipment.

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