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In an interview recently, someone asked me what is the major hardware level difference between a WiFi module (ESP8266) and RF module (nRF24L01+) that I had used in my projects.

I mentioned that both use the 2.4GHz spectrum but the actual frequencies within that spectrum are different in both and also that the WiFi is a more optimized version of RF due to techniques such as beam-forming. The interviewer rejected my answer and said that the major difference is in the range of both, with RF having the greater range.

I believe that range is not the difference and RF’s range is only greater with an external RF amplifier which can also be used for WiFi to increase its range.

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    \$\begingroup\$ Was the interviewer specifically referring to the nRF24L01+, or just "RF"? It doesn't get much more generic than "RF". In the context of WiFI, RF is merely anything that isn't WIFI. Plus who is to say that one gets better range than the other? That would depend on the antennas, protocols, and usage. \$\endgroup\$ – Bort May 21 '19 at 23:33
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    \$\begingroup\$ Yes we were specifically talking about the nRF24L01+ module as I had mentioned that in my CV. I couldn’t stand the interviewer saying that it has a greater range as it has nothing to do with this module rather a RF power amplifier and antenna that just amplifies that signal for greater ranges. \$\endgroup\$ – Marry35 May 22 '19 at 5:57
  • \$\begingroup\$ Both of you were wrong, alluding to specifics which could be true in other contexts but were false in the context actually under discussion, while entirely missing the many things that were actually true. And labelling an nRF24 "RF" hints at a real lack of familiarity with the breadth of that term and lacking knowledge of the specificity of what an nRF24 is. \$\endgroup\$ – Chris Stratton Dec 12 '19 at 20:55
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Sorry about the bad experience you had, that sounds frustrating and not too productive. I think it's important to have discussions like these as if you're disagreeing with a co-worker, not with an interviewer. If the interviewer disagrees in a way that's problematic, that will tell you something about the team, but if you're faced with a difference in understanding it can be useful to try and unpack it.

I know if I were faced with the question I'd have said something to the effect that: "the nRF24L01+ is proprietary and usually requires the designer produce both ends of the communication channel like a wireless keyboard and dongle, while Wifi is a standard that allows designers to build things that interact with other wifi devices." Mostly I think if you speculated responsibly and spoke coolly to your experience you probably did all-right on that part.

Either way, send a thank you message and take some notes on what you learned about the team or position in case it went better than you thought.

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    \$\begingroup\$ With all respect, most of this answer seems like it belongs on workplace.SE \$\endgroup\$ – Bort May 22 '19 at 2:26
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    \$\begingroup\$ I think I handled the interviewer well. He looked very confused for a second after I gave my rebuttal to his answer as I was not willing to take his weak argument against my answer but then, he would’ve assumed that I only had the surface knowledge of the topic. \$\endgroup\$ – Marry35 May 22 '19 at 6:01
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    \$\begingroup\$ But then again, your Interviewer is not some wizard and he/she could be wrong and it’s important to let them know to show that you know your stuff well. \$\endgroup\$ – Marry35 May 22 '19 at 6:05

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