Signal Strenght Too Good

General Wi-Fi Network Observations
1

Just read the Metageek article “Understanding WiFi Signal Strength” here: WiFi Signal Strength Basics | MetaGeek. Clearly stated is that 30 dBm is the maximum limit. Attempting to assess my own LAN with inSSIDer and by Linksys EA7400 is generating a strength of -20/-22 at 2.4 GHz with some occasional blips and -22/-25 at 5GHz. I have confirmed with several other Android Apps on my Galaxy tablet.

I am new to this and question just what to trust.

Ed

2

Hey @eandjrich! I originally wrote that guide, although it’s been adapted a couple of times for various purposes around our website. When I said that -30 dBm isn’t necessarily desirable, I just meant that it’s really no better than -60 dBm. I didn’t want people to get hung up on trying to achieve “100 percent” signal strength, because there really is no such thing in Wi-Fi. Basically, anything -60 dBm and up is “good”. Don’t be concerned about seeing -22 or -20 dBm off your router. That does mean the power is probably pretty high, but in a home Wi-Fi environment… it won’t hurt a thing. :+1:

Thanks, and have fun!

3

Joel, not a question of your saying “-30 dBm isn’t necessarily desirable…” but in the Signal Strenght table "-30 dBm Amazing “Max achievable signal strengh. The client can only be a few feet from…” Mine is even stronger that the “max achievable.”

Admittedly a minor technical issue with my primary focus on determining why one WLAP in my apartment with a significantly weaker signal strength than another in the hall but closer has significantly higher down and upload speeds. Of course difficult to stay connected to the weaker access point because as you explain the setup is designed to switch at some drop in the level of output and it even starts out lower.

Ed

4

Hi @eandjrich, generally speaking, -30 dBm is around the max that you’ll ever see, but this is a classic case of “it depends”. This article is intended to give some general guidance, but not establish hard rules, as there are very few hard rules in Wi-Fi.

I hope that helps, thanks!

5

Would make it easier to trouble shoot if we had more hard rules. I have pretty much proved that connection with the closer of two access points and the one with the strongest signal yields significantly lower download and upload speeds. Of course you have to go to some trouble to connect to the weaker signal and stay connected to observe that it is actually the faster.

Ed,

6

There are a bunch of things that can make one access point slower than another:

  1. What kind of backhaul does the AP have? If your client is connecting on the same radio that backhauls to the other AP, then expect a performance hit since the radio has to rapidly switch back and forth between serving the client, and doing backhaul. If it’s a triple-radio AP, then they can dedicate one radio to backhaul. Best-case scenario, of course, is Etherent backhaul.
  2. What band is your client connecting in? 2.4 GHz is usually more crowded than 5 GHz, so if your client is associating in 2.4 GHz… you’ll likely see less performance.
  3. What are the capabilities of the AP? If it is a good, 3x3 AP, great. If it’s only 2x2 or 1x1, then you’re going to see less performance, because it can’t hit as good of data rates.
  4. What is the channel width? In 2.4 GHz, we’re pretty much limited to 20 MHz, but in 5 GHz, you can use a 40 or (sometimes) 80 MHz channel. I like to make my AP’s match across the board - I always use the same channel width on every AP.
  5. Is the second AP on a worse channel? Maybe it’s a congested/crowded channel, so it performs worse than your first AP.

I hope that helps!

7

Joel,

#1 about backhaul is right now over my head and will do some reading and check with the local tech that from the IT division that takes care of our WiFi.

#2. “What band is your client connecting in? 2.4 GHz is usually more crowded than 5 GHz, so if your client is associating in 2.4 GHz… you’ll likely see less performance.” Client is connecting to 5 GHz for both these ACs

#3. “What are the capabilities of the AP? If it is a good, 3x3 AP, great. If it’s only 2x2 or 1x1, then you’re going to see less performance, because it can’t hit as good of data rates. What is the channel width? In 2.4 GHz, we’re pretty much limited to 20 MHz, but in 5 GHz, you can use a 40 or (sometimes) 80 MHz channel. I like to make my AP’s match across the board - I always use the same channel width on every AP.” These are ExtremeWireless AP 410C’s with 5GHz 4x4:4 spec. Both display that they are using an 80 MHz channel width

  1. Is the second AP on a worse channel? Maybe it’s a congested/crowded channel, so it performs worse than your first AP. Very improbable as my apartment is at the end of hall and for since this new WiFi building coverage was installed I have had no neighbors in the two adjacent apartments that are actually opposite each other. I do pick up two other access points with slightly less strength but better than -70 which must be on the floors below and above. However remember this is a continuing care facility and in these apartments reside us older folks with most very uncomfortable with technology let alone change. Most were using Comcast or Verizon as their ISP’s and I few have yet changed to the “free” new service :slight_smile:

I will spend some time with the tech tomorrow and post what I learn.
Ed

8

Local tech for our Continuing Care Facility was not familiar with backhaul. I do know our LWAP’s throughout the building are connected by Cat6 in wire closets on each floor to what must be either a WLC or a switch. Glass carries the signal back to some central point where we our connected to the Internet via a Comcast cable. Interesting, Ethernet to Glass to Coax to the Ethernet Internet.
Ed

9

dBm values are usually negative, and the closer the value is to 0, the stronger the signal. For example, -20 dBm is a very strong signal, while -60 dBm is still good, and -80 dBm may be considered fair. The -30 dBm limit you mentioned in the MetaGeek article might be related to avoiding overpowered signals that could cause interference.
Regard,
tindermodapk.pro

10

Interestingly, even if the signal from access points is strong, this does not always guarantee high speeds. There are several factors that can affect performance.

If one AP is connected via Ethernet and another via radio, this can create asymmetry in data transmission. Hybrid configurations often require fine-tuning of QoS (quality of service). I recommend checking how the roles of the points are distributed in the network and possibly putting one of them in mesh repeater mode.

Even seemingly “clean” channels can suffer from hidden interference, such as from Bluetooth devices or microwave ovens. Tools like Ekahau Sidekick or professional solutions such as Managed SOC as a Service (more information: SOC-as-a-Service: Andersen's Security Operations Center) not only analyze the spectrum, but also automatically optimize network parameters in real time.

11

You said it right: a strong signal doesn’t always mean high speed.

Besides, there are a lot of reasons why the speed may be low. For example, the channel may be congested or the equipment may not be very good.

Even if you have a wide channel (80 MHz on 5 GHz), there can be problems if there are devices nearby that cause interference.