Noticed the low SN has a catch diode. Was it later added internally?
The datasheet doesn't indicate they have a diode internally. I think some of these were in a system wired in parallel. I will check for internal diode when I test them further.
If I were to sell these power meters, should I do it the Chinese way - meaning I wouldn't include any documentation or instructions? I was gaming out how I would respond to a customer and it would go down like this -
Buyer: "I connected the power meter to a 50 W ham mobile radio. It worked for about 2 seconds and now it doesn't even light up the display and it smells strange!"
Me: "Well first of all, did you read the instructions included with the unit?"
Buyer: " No! There were NO instructions included! I thought there was something amiss."
Me" "Well that's the problem right there. You admit not reading anything and you realized something was missing.
Buyer: "But why were they missing?"
Me: "Environmental waste reduction initiatives. If you already have this meter and just bought another one, you wouldn't need another set of instructions."
Buyer: "But I never had one before!"
Me: "You should have contacted me to get the instructions then. I can't be responsible for you not understanding how it operates if you didn't even want to go to the trouble to get documentation. I'm under strict controls to reduce paper waste. The documentation also includes a red warning label to be installed by the RF input so you will be advised not to go over the power limit."
Buyer: "Warning? Red label? What warning!"
Me: "However, since you reached out I will be happy to send you the instructions and warning label so you will understand where you went wrong - at no charge to you! Also a sneek preview of new upcoming products."
Buyer: "
"