Good question, the front-end attenuator is rated at 18dB return loss, for 9kHz-6GHz, so probably not reflections saving it (assuming small reflections from the connector and transition). I did wonder about reflections impacting the other power sensor, but if they do it's below the error of the cheap sensor anyway. Once again, great video!

I was going to ask the same thing!

The crazy thing is that you can get a breakout board with an SMA connector for the AD8317 for just over $5. If you're willing to use external attenuators, a DMM, and the table from the datasheet to convert the voltage into dBm, you'll get that performance for around $5.

Dodgy mounting is probably what killed the battery, too: I didn’t even know Li-ion cells could leak 😂

It's typical for this stuff to have specs beyond reality, if it sounds a little too impressive divide by two and you'll usually be close enough.

@@Broken_Yugo I wouldn't say "specs beyond reality", since most of these manufactures of cheap test equipment often just goes with whatever they can squeeze out of the components and label the product accordingly. It technically can measure power at 10 GHz, it just doesn't do it particularly accurate compared to how it fairs at more reasonable frequencies. Similar for power. It apparently "can" measure 30 dbm, I thought it would fail here honestly, but my expectation were that it would take a few seconds, perhaps a minute. Though I can also see ambient temperature play a meaningful role here. I have thus far not seen many cheap pieces of electronics test gear that makes claims beyond reality, but rather specifications that are based more on technicalities. I will though say that the claims by the manufacturers aren't honest, since technicalities is not what a buyer expects... In the end, the claims made are far from what we see in other fields where a 300 lumen flashlight is sold as 80 thousand lumen. Or a 200 foot pound impact driver being marketed as 3000 foot pounds. But yes, we should still be skeptical and point out these sorts of factual errors in claims, else electronics test gear manufactures will also stumble down into absurd performance claims.

I have bought and repaired many of things you see also.

he designed that thinf

I’m not an expert on all flavors of the ESP32, but I know EEPROM can be emulated using the on-board flash memory; not sure if there is a limit on the size. Using flash is non-ideal due to the limited number of writes, but for a calibration table which seldom if ever changes, that’s OK. With savvy programming, it ought to be possible to improve accuracy a lot. The problem is that doing the extensive calibration would take time and raise the cost of the device.

Data sheet maximums are normally "never exceed" values.

Other than the battery, which isnt really needed, what part is going to wear out?

@@stargazer7644 I agree, but they are possibly calculated on the basis of continuous operation at the highest allowable ambient temperature in this case. 1 watt of RF power is being dissipated somewhere, most likely as heat. It's not the same as a DC overcurrent case, but I think the thermal stresses will damage the chip eventually. Unless of course it's wildly underspec'd or Shahriar got a particularly robust one!

Probably the same issue as the dBm readout: It just shows the value _after_ the internal attenuator (which is used to reduce the signal level so it can be measured properly). Which doesn't make a lot of sense because the device could just calculate the actual value from the measured value and attenuator setting.

No, I do it manually to save your eyes. :)

The USB is only for charging.

@@Thesignalpath FYI, I just got one of these and under Win 10 OS, it installs a serial port and the V5 win program will read the power data around 10/sec. Pretty easy. Not sure yet how set the freq vs reading table. Seems way off on mine, but for any given frequency once set its accurate.

Yes, charging only.

The unit I have uses the usb for a serial adapter. You have to load the driver, I asked the ebay seller for the link to the software, he sent it, and I have my USB connected to the computer running the software... My unit also has the manual on/off power switch..

PE43601MLI for the attenuator? AD8317 for the log amp. The second one can be seen on the PDF.

@@jaro6985 I am probably dumb - cannot find a PDF

@@ghlscitel6714 The PDF in his video that he is looking at the schematic. PE43602 you can search and the third link in google has a datasheet, micro semiconductor.

Put an external 10 dB attenuator between them if you're concerned about that.

It doesn’t. It can’t.

Just buy one and you can see it blow up first person! :)

Of course.

The tracking error or losses of the splitter are not relevant here. We are doing a symmetric comparison between its two ports. A resistive splitter like this one has exceptionally well matched outputs.

@@Thesignalpath 0.25 dB (which is the spec for that splitter in the frequency range of interest) is not insignificant when comparing power standards with one another. As i said i agree that for your experiment it is good enough.

Yes, there is an uncertainty of 0.25dB, you are right. The VSWR of the cheap power meter also changes with the attenuation and that causes a shift.

This device can be relied at best +/- 2dB for any individual measurement.

Then why not 20 ghz? I suspect the equipment they tested it with was dodgy! The manufacturer may be completely honest but a bit unqualified.

Yes that is what he said.

It sounded like he said that microcrystalline cellulose is used in cosmetics and thats whats in the swab, its just regular cellulose that happened to have a spectral match with the microcrystalline cellulose in the library based on the Raman they are the same@@-vermin-