Measuring rf power around 300 MHz

Thread Starter

mj3

Joined Apr 19, 2016
2
Hi all,
I'm trying to measure the power of an rf signal that frequency ramps over 200-400 MHz. My signal strength as measured on a spectrum analyser is around 0 dBm (into 50 Ohms) post-amplification (expects 50 Ohm load), but I'd like to know the total power in this band without requiring the analyser. Ideally I'd be able to measure Vrms or an associated quantity.

Naively I considered rectifying the signal and charging a capacitor, but given the high frequency and (relatively) low amplitude of the signal I'm not sure this would work. Is there any "obvious" solution to this besides purchasing test equipment?

Cheers
 

Kermit2

Joined Feb 5, 2010
4,163
If you can measure then get rms value with either a scope or a high impedance volt meter you will get a very close approximation of power levels
Most of the error between theory and practice will be due to inefficiency of antenna matching. High SWR is a real Watt killer.
 

Thread Starter

mj3

Joined Apr 19, 2016
2
Unfortunately I don't have a scope with high enough bandwidth to directly see the rf, which is why I'd like to convert it to a power measurement. I'll check out the Wattmeter, but would something like the AD8361 or MAX2014 be a cheap solution?
 

MikeLogix

Joined Mar 1, 2016
4
I don't think a Bird watt meter can measure the small amplitude signal (0 dBm) as stated by mj3. The Bird meter requires at least 100mW.
 
Top