Got a couple of cheap RF SMA Wattmeters. (both are bottom of the barrel)
One is an older USB3 fellow from China with some years on the back since I purchased it, it goes from 0Mhz to like 10 or 11Ghz, - it can both be used as a stand-alone unit with its OLED display that got a 10log frequency bank where you can have different dbm-offsets for each of the frequencies you put in.
The unit can also be hooked to a computer for graphing alongside adjustments with 3 different speed settings.
Testing HackRF signal generator output that peaks around 24.22mW at 2.445Ghz on this RF-meter..I recall the HackRF is rated as half duplex with around 25mW of max RF output-power, but got no idea at what frequency that output was rated, as the hackRF RF-power is highly variable across its output span that peaks at 7.25Ghz, though with some frequency drift from 6.9G to 7.25Ghz.. up to 6.9Ghz its spot on, but obviously with minute RF power up in those multiple gigahertz.
The other one is from this year, and got it for some cheap handhelds I purchased..
its spec-rated at max 120 watt and got a range from 125 MHz to 525 MHz according to manual.
Its this one below that costs around the same, and is not PC-compatible.. it got a few features on its screen.. shows forward & return, alongside SWR but the SWR needs some juice before the SWR reading will play along,.. the wattmeter also needs around 0.5 to 1 Watt, so not a unit for smaller values.
Wattage test on the quite popular Quansheng K5, as it is cheap as, and you can mod it with games, s-meter, pong, spectrum, and 18Mhz to 1.3Ghz span, and more or less anything under the sun.
At 17 US delivered to DK with incl.VAT (25%) and charging cradle, - Im quite impressed with this K5 unit, and its cleaner than my Jianpai8800plua which is a radio too around 300% more and around 50 bucks, though with Bluetooth app & GPS, and all that yazz.
Quansheng K5 wattage test _ low 1.55W / medium 3.43W / high 4.94W at 146.2Mhz (battery somewhat full 8.1v) with a 20W dummy load attached.. the SMA dummyload was incl. with the wattmeter. (wattmeter-price was a tad over 30 bucks with a little shipping cost on top incl. EU-VAT/danish25%)
Wattage test of the Jianpai8800Plus (if others have tested these radios with better wattmeters would love to hear the results, to put mine into perspective, though both of these radios.. seems to be highly voltage-depended and how full the battery is' and what amount they can deliver)
Low 2.04W / High 5.87W at 146.2Mhz (battery 8.0v)
Manual of the latter RF SMA wattmeter, unit is fitted in a metal box with an inbuilt LIPO cell.. (front/back page)
The manual states an SWR detection range at +3watt (highlighted in the spec box upright front page, click for increased resolution).
Haven't checked the SWR accuracy yet on this 125Mhz-525Mhz return/forward/swr-wattmeter, though my only tools for that would be either the TinySA Ultra with a sweep/CN-bridge or these older 130-2.7Ghz antenna analyzers.