Does this seem logical?
1. The signal strength (example in dBm or mW) from a transmitting source is measured.
2. Assuming most of the attenuation is due to free space loss, the free space loss factor is "added" back to the measured signal to get the ERP of that specific radiation lobe (it could be main, side, or back lobe).
3. The transmitter output is a known value (example 2 Watts).
4. Using the calculated ERP for a specific lobe, I can use the following to determine the loss / gain due to the antenna & cable: loss/gain = 10 log (transmitter output / ERP specific lobe).
5. If I rotate the transmitting antenna to 360 degrees, then I should be able to have a rough picture of its azimuthal radiation pattern at a certain elevation angle.
I'm probably using the terms the wrong way because I think ERP is synonymous to the main lobe of the antenna (right?). But I'm just treating the ERP as specified only to a certain lobe without knowing if its the main, side, or back lobe.
I'm really not sure if this is right. I just want a confirmation whether my logic is wrong, and if so, why? Thanks!