Measuring WiFi EVM

Thread Starter

Mayur_sarode

Joined Aug 26, 2020
1
Hello all,
I am looking for opinions on learning Wifi EVM when it is sending TCP packets . I have a WiFi board but it doesn't have any RF test mode .
Has anyone done it before ?
Looking forward to any tips or experience.
 

slackguy

Joined Feb 11, 2016
67
if you mean "the number of bars", there are articles showing the "bars lie". signal strength does not mean the "packets are received", and some units just plain lie about the number of bars, some units need more bars than others to hear something.

don't car about bars, care about speed. plenty of online articles about getting a better signal

there are two types of boosters: "signal level boosters" (sold in PC stores - one i tried was bumpkiss and i returned it) and "digital repeaters which use appropriate time delay so as not to damage nearby cell signals" (cell towers)

i think a building in my area has an illegal booster: the telco tells me they have the area covered but whenever i'm near the area my phone doesn't work. some government offices i think, some IT staffers, installed illegal boosters i bet ? :)
 

Janis59

Joined Aug 21, 2017
1,227
As the even meaning of EVM is still under disputes (https://en.wikipedia.org/wiki/Error_vector_magnitude) I am not doubt is there a good meaning to measure it. If the aim was measure the maximum distance then better probably is to measure the distance at which the algorythm of to send the telegram again and again when packet parity control flags wrong parity checksum become unable to repair it. Actually, both existing options (Lora and Nordic) uses this algorythm, thus the caching the teegram are many times repeated means this distance is overstepped. So, take a good Picoscope with larger memory and listen the line. It allows to analyse signal bit by bit in it`s memory. Or contrary - send something from comp to it back and compare the received/translated packets by computer.
 
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