I'm having trouble making sense out of this requirement, in terms of how to test for it.
I have a specification stating that for an RF power level measured in dBmi (let's call that power level S dBmi), a specific result should be obtained in a test.
As part of that test, I have a receive antenna that I must use and it is not isotropic. Not only that, it includes gain and loss internally, so its performance is just not a matter of the beam shape. A measurement at its output would include its pattern gain and its internal gains and losses.
There is a passive transmit antenna of known gain at a known distance away and a controllable signal source suitable for producing the required signal. (Let's assume it's a CW signal, to keep it simple.)
How would I set up for that test? How and where would I verify that the RF signal level is correct?
I assume the requirement means that if I had an ideal isotropic antenna, with no internal gain or loss, then the RF power measured at its output should be the specified level S in dBm (where the "i" for isotropic is now implicit in the setup). If that's the case, I could just measure the RF signal at the antenna output and radiate from a source at the power level that meets that requirement.
But where do I go from there? I can calibrate using passive antennas, like horns, but ultimately, I need to know how to set this up with the required antenna.