[clubjoker]

A100L2 anemometer:

"The A100L2 has a "secondary" analog/voltage output signal in addition to the "primary" pulse/frequency output signal, however the analog/voltage signal is less accurate (see specsheet) and we advise that only the pulse/frequency signal be used in applications requiring the highest accuracy (such as Wind Assessment). Please refer to the A100LK for a similar anemometer with pulse/frequency output signal only."

It uses the same  pulse output as the A100LK therefore < 5V and works on mine.

Thank you! As well as being wrong about the signal voltage, which you've pointed out is 5V and therefore fine for the Weatherduino, I think I conflated the supply voltage with the signal voltage. Do you run a higher voltage supply to the A100LK from the Weatherduino TX (9V / 12V to meet the specified min 6.5V) or does it run ok on a 5V supply?