If I were you I would use a simple tuned circuit and high impedance RF voltmeter or oscilloscope to measure the instantaneous RF voltage into some load.
No you could notand should not use any SDR as they are designed to adjust their gain according to the received signal which will make the readings fairly useless, I'd suspect.
You could use a simple signal strength meter made with a diode, which would still be nonlinear due to the nonlinearity of the diode.. whatever it is. They all have some nonlinearity, also lack sensitivity at lower signal levels.
Detector circuits are designed to attempt to overcome these problems. Impedance transformations are used to present a detector with a high enough voltage to overcome the diode's threshold.
Hi,
I have an antenna made of a ferrite rod/coil and a capacitor that is tuned to 77.5kHz. Connecting it to the High-Z input from my RSPduo I can identify the DCF77 signal well, which also gets more or less weak depending on how the antenna is oriented.
So far all as expected.
I would like to determine the power that is received over the antenna, as in electrical power in watts (or probably microwatts). Can this be done with SDRplay or another software? Ideally I would like to know the (max) voltage of the signal as well. The spectrum and waterfall display show only dBm which vary depending on the selected RF gain. I'd like the real power and voltage the antenna receives before amplification / processing by the SDR.
How can this be done?
Linrad allows dbm measurements if the radio is pre-calibrated.
Its pretty good for this, actually. For time signals like DCF77 (and WWV and WWVH) you can use a roll of coax as your antenna, tuned to the DCF77 frequency with variable and or fixed capacitors.. like mica caps.
This is described on febo.com in the projects area.