Page 2 of 2

Re: meshlium code

Posted: Tue Mar 07, 2017 7:44 am
by engmayarkamel
Dear Libelium


IS RSSI in dbm or just indicator? regarding the values i get all readings in positive except one reading which is -1. the -1 value is not from far access point its near so how come im getting -1.
how it is dm and the values are +ve as far as i know the values in dmb should be -ve.

thanks

Re: meshlium code

Posted: Tue Mar 07, 2017 10:21 am
by engmayarkamel
so i understood from you that RSSI unit is in dbm and if the value increases ex(70,80,100) it means that its closer to the device if the values ex(-1,-2) means they are far away, right?

Re: meshlium code

Posted: Tue Mar 07, 2017 11:11 am
by libelium-dev
Hi engmayarkamel,

Yes, this device with a -1 value is very far, or in other case, this device has not enouth power to determinate signal quality.

Best regards

Re: meshlium code

Posted: Sun Mar 12, 2017 7:35 am
by engmayarkamel
Dear Libelium


what is the range of RSSI?

Thanks and regards

Re: meshlium code

Posted: Mon Mar 13, 2017 1:28 pm
by libelium-dev
Hi engmayarkamel,

Sorry for the misunderstanding of the previous posts. Let's explain the RSSI limits and measure units in Meshlium 3.

WiFi: usually go from 0 to 60. -1 indicates that the device is very far or it has not enough power to determinate signal quality.
In WiFi, the value is an arbitrary integer established by the microcode on the adapter and by the device driver. In Meshlium the chipset is Atheros, and the RSSI conversion found is:
Unlike the other vendors described, Atheros uses a formula to derive dBm.
RSSI_Max = 60
Convert % to RSSI
Subtract 95 from RSSI to derive dBm
Notice that this gives a dBm range of –35dBm at 100% and –95dBm at 0%
from viewtopic.php?f=4&t=14833&p=43520

Bluetooth: usually go from -40dBm (nearest nodes) to -90dBm (farthest ones).

Hope this can solve all your doubts about the RSSI in Meshlium. Do not hesitate to ask any other question you may have.

Best regards,

Re: meshlium code

Posted: Tue Mar 14, 2017 7:32 am
by engmayarkamel
Dear Libelium


1) regarding the range of the wifi you mentioned that it goes from 1 to 60, but im getting 75.

2) can you please write the conversion of RSSI in a formula because i didn't get the steps

3) what do you mean by (Convert % to RSSI) , is RSSI in %?



thnaks and regards

Re: meshlium code

Posted: Tue Mar 14, 2017 10:50 am
by libelium-dev
Hi engmayarkamel,

The information we gave you is the information we have. Why are you getting 75 if the limit is 60? We do not know, according to Atheros, they usually use this range of values. Other companies like Cisco uses from 0 to 100.

We don't have any formula to convert WiFi RSSI. What we posted, is the information we get googling or seeking in this forum. If you want to convert this RSSI in meters, for example, we recommend you making some tests in the real location.

Best regards,