What's the cheapest way to mesure power of RF output(such as wifi router) ?

[youta556]

I want to compare output power of 2 wifi routers.
Both 2 routers have sma antenna ports.
I have no professional power meter such like keysight V3500A,bird 43.
What's the cheapest way to mesure power of RF output(such as wifi router) ?

[cdev]

Hi! Welcome to eevblog!

A wifi router's power output is very small and high enough in frequency (2.4 GHz ) that measuring it is likely fairly difficult.

A directional coupler might help. I was able to get a field strength meter to deflect.. It used an 1N34 diode as its detector.

A dummy load might help.. a non-reactive 50 ohm resistive load..

Which router has an SMA jack for its output?

[Ice-Tea]

Decent chance you'll find they are the same or very comparable. There's a regulatory limit. Unless you're taking bottom dollar units, you can be pretty sure they're turned up as far as allowed.

[cdev]

MiniCircuits sells power detector modules that may be exactly what you want, giving you what is in effect a sensitive RF power measurement device.

[dcarr]

Search eBay for "crystal detector sma" and "diode detector sma".

These accept RF on the input SMA and produce a voltage proportional to the power in dBm on the output connector.  You can read them out with a voltmeter for steady signals or with a oscilloscope for pulsed signals.  It looks like there are options from $30-70 that would work at 2.4GHz.

[ledtester]

Two "out of the box" ideas...

1) a "wifi signal strength" phone app; I have one that shows dBm -- might be good enough for at least a comparison

2) look up the test results filed with the FCC; go to https://fccid.io/<FCC ID>, e.g.:

https://fccid.io/W5HSBG6580

[dcarr]

2) look up the test results filed with the FCC; go to https://fccid.io/<FCC ID>, e.g.:

This is clever.  I like it.