topic Re: RSSI low even when really close to an accesspoint in Wireless

RSSI low even when really close to an accesspoint

Bartvdm — Mon, 05 Jul 2021 17:26:05 GMT

After a survey we placed 12 access points in our warehouse. 3802's with 4x AIR-ANT2535SDW-R dipole antenna's each. In the WLC (2504 wlc) antenna gain is set to 6x0,5dBi for each accesspoint.

We are using 2.4ghz only, 5ghz has been disabled (but when I enabled it I saw simular results)

I walked around in our warehouse checking the WLC client page and noticed that I never got a better RSSI then -60 dBi at best (8 meters from the accesspoint hanging on the ceiling) this is more or less the same for every accesspoint.

I manually adjusted powerlevel for the 2.4ghz antenna's to 2 (it was 4,5 or 6 for all accesspoints), so I expected a huge increase of the RSSI, nope.. -55dBi at best from that 8 meter of those accesspoints.

I then got into a forklift and got close to 1 meter of that accesspoint (powerlevel still set to 2), RSSI went up to -45dBi, still far from what I expected. (I was expecting something in the area of -35 or even -30 when being so close to the AP)

any idea where this problem is coming from?

Thanks a million!

Re: RSSI low even when really close to an accesspoint

fdharmawan — Mon, 20 May 2019 02:01:53 GMT

Hi Bartvdm,

When you said "I manually adjusted powerlevel for the 2.4ghz antenna's to 2", did you mean the power is 2/7 (17dBm)?

Re: RSSI low even when really close to an accesspoint

patoberli — Mon, 20 May 2019 08:29:39 GMT

Why do you want such a strong signal strength in 8 meters distance?
Do you have coverage issues?
I've barely ever seen more than -40dbi, but I also haven't really measured that a lot of times.

Re: RSSI low even when really close to an accesspoint

Bartvdm — Mon, 20 May 2019 09:33:15 GMT

Hi fdharmawan That is correct

Tx Power Num Of Supported Power Levels ............. 7

Tx Power Level 1 .......................... 18 dBm

Tx Power Level 2 .......................... 15 dBm

Tx Power Level 3 .......................... 12 dBm

Tx Power Level 4 .......................... 9 dBm

Tx Power Level 5 .......................... 6 dBm

Tx Power Level 6 .......................... 3 dBm

Tx Power Level 7 .......................... 2 dBm

Tx Power Configuration .................... MANUAL

Current Tx Power Level .................... 2

Re: RSSI low even when really close to an accesspoint

Bartvdm — Mon, 20 May 2019 09:34:20 GMT

because I did a survey, and the results where dramatic, coverage would not go below -60 is 95% of the warehouse

Re: RSSI low even when really close to an accesspoint

Jurgens L — Mon, 20 May 2019 11:30:43 GMT

When using the AIR-ANT2535SDW-R at 8meters you won't get the optimal performance out of it as it's not designed to be that high.

In warehouse environments where AP's normally need to be installed higher than 6m, directional antennas is a better option.

Re: RSSI low even when really close to an accesspoint

fdharmawan — Tue, 21 May 2019 02:13:04 GMT

Hi Bart,

Any reason why did you raise the tx power level to such high level? If you complain about the RSSI around -60dBm, may I know what is wrong with that? I guess -60dBm falls on good-to-perfect signal. The WiFi signal meter is still full bar, right? Do you have any connectivity issue such as ping over 10ms or traffic performance?

If I were you, I would not set the power manually and let the RRM does the job. Besides, sometimes the greater the power might not equals to better WiFi signal.

Re: RSSI low even when really close to an accesspoint

fdharmawan — Tue, 21 May 2019 02:15:05 GMT

And one more thing. RSSI is client stand point. The AP might 'see' your laptop but your laptop wireless NIC might not 'see' the AP. I forgot the term in this but your laptop's wireless NIC have a range too.