topic Re: minimum good -dbm for site survey? in Wireless

minimum good -dbm for site survey?

baselzind — Mon, 05 Jul 2021 18:52:23 GMT

i need to do a site survey for a warehouse to cover weak spots , my question is what is the minimum very good -dbm for the ssid where at the point it start deteriorating i know i need to add a new ap to cover this spot? -40 dbm? -50 dbm?

Re: minimum good -dbm for site survey?

Rasika Nayanajith — Wed, 18 Mar 2020 17:56:56 GMT

In a general deployment trying to keep -67dBm at cell edge. Assuming typical noise floor (~ -92dBm), you will get 25dB SNR, higher the SNR is better.

Even if you use site survey tool, it is important to check this RSSI value on devices that use in that environment (as RSSI value is relative to device you use, cannot compare different type of devices)

HTH

Rasika

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Re: minimum good -dbm for site survey?

baselzind — Wed, 18 Mar 2020 18:30:36 GMT

so on my survey tool as soon as the signal strength go higher than 67-dbm i know this area have a weak signal and need to be covered?

Re: minimum good -dbm for site survey?

Rasika Nayanajith — Wed, 18 Mar 2020 18:43:35 GMT

What are the wireless devices customer use in that warehouse environment. I would check RSSI value on that device when your survey tool shows -67dBm.

What you really look for is actual device RSSI value (for example when your suvery tool WiFi NIC will show -67dBm, where as actual device show -73dBm). In that example it is 6dB difference and you have to get cell edge to -61dBm if you are survey given survey tool

Here is a good post to refer

http://wifinigel.blogspot.com/2014/10/survey-for-your-wifi-clients.html

HTH

Rasika

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Re: minimum good -dbm for site survey?

Haydn Andrews — Wed, 18 Mar 2020 21:05:22 GMT

Having done a lot of warehouse designs this really depends on the device requirements.

Some of the devices can be 10 or more dBm different from the survey equipment (sidekick/ dongles) so you need to make sure that you look at what their requirements are.

Some devices will also have the ability to tune what dBm they start to look at roaming which is always best to look at that as well to ensure they are optimised for the wireless design.

Normally I design for -67dB but from the most significant least capable device point of view. I have also found that in the warehouse environment that utilising 5GHz if you can have a huge improvement.

If allowed also look at using directional antennas rather than Omni's

Re: minimum good -dbm for site survey?

Edu — Thu, 02 Apr 2020 13:12:52 GMT

Hi.
So, I like to use these configurations.
Signal -67 dBm
SNR 25 dB
Data Rate = depends on what kind of application that you will use.

One characteristic of the most part the warehouses is, to use a directional antenna.

Re: minimum good -dbm for site survey?

baselzind — Tue, 07 Apr 2020 07:51:20 GMT

what is RSSI and how do i find it out?

Re: minimum good -dbm for site survey?

Scott Fella — Tue, 07 Apr 2020 14:05:42 GMT

Just search Wireless Site Survey Best Practice” you should find more than enough info on that and what you searched for.