Wireless Coverage Survey, measure twice, install once.
Have you heard the phrase, "Measure twice, cut once." ?
Carpenters know it's important to know that the measurement is perfect before cutting the board.
Many people skip the most important step in setting up a wireless network in the office, large home or in the warehouse.
I've surveyed over a thousand cellular communication towers in the USA and have developed a commercial process that produces a coverage map good to about 24' over a 3 mile area.
I'm going to show you how you can conduct your own coverage survey at work or at home and then we can setup and install your wireless network so you have the speeds you pay for.
If you're still reading the bars as your point of reference for signal strength you're kidding yourself on speed.
I'll list the apps that you can download and install which will generate the information we need to make your home a fast wireless instead of just wireless.
First I need to bring you up to speed on a few things.
If your wireless device claims 300Mb/s transfer cut that in half because most all wireless devices we will work with are half duplex. That means the wireless device can either send or receive but can not do both at the same time.
So let's say the top speed you can transfer over your LAN (Local Area Network within your Wireless network) is about 150Mb/s.
When we add IP transfer overhead, errors and other things we basically get 124Mb/s transfer tops.
That's fast in any measurement but it's only going to happen with good equipment and great signal. That means above -60dbm signal levels.
Ok, let's see some signal measurements...
- 40's to high 50's = full data speeds of up to about 150Mb/s.
- 60's are about 1/2 or near 64Mb/s.
- 70's on the low side can be 48 to 52Mb/s
- 70's on the high side are going to start dropping off fast 30MB/s to 18Mb/s
- 80's means you're in the Kb/s ranges and is worthless if it's in your office or home 80's.
When you see the marketing material about how much your Wireless can cover make sure you visualize 80+db in the areas the marketing material shows it covers.
You can basically do what I do and say 140Ft max and subtract 10 feet for a normal wall obstruction.
I surveyed a 3,000 sqft home last week and came up with coverage with one AP mounted in the center of the house.
Coverage doesn't mean you can do everything.
0 to 50 feet: I calculated that the connections within 50 feet of the AP could stream HD 1080 on 3 TV's and have 5 devices streaming HD Audio.
50 to 75 feet: Good audio streaming 720p video and fast surfing.
75 to 100 feet: Good web surfing.
100 to 125 feet: Spotty with dial up response for most internet surfing. Not able to stream.
When I survey a home I include the front porch and the back yard patio areas.
This home is nearly 165ft long with just enough to offer -75db inside far walls. This is my bottom line signal and makes it impossible to enjoy streaming outside on a cool evening so it's not what I've designed.
By adding a second access point and staggering the installation points I can cover inside walled rooms with -65 and outside patio and porch with the same. Now we have coverage from -42db to -65db and everything streams fine.
Have you heard, "Can you stop streaming because I'm trying to download a file for work?"
If you have then a survey like this with a AP, Router and Switch review might be in order.
I've setup my Wireless to limit the speeds to 35Mb/s even if it reads 54Mb/s it's sustained transfer rate is 35Mb/s.
This means I can stream my HD 1080 over more than 3 TV's without causing everything to buffer up and slow downloads. My slow point now is my switch which I have installed a smart switch and have given priority to select devices in the Wireless network.
Sounds complicated doesn't it?
It is, but, if you let me or any technician I've trained to do your survey I can say you'll get the best design coverage possible. The only variable to having a perfect network is your willingness to spend a few hundred to make it perfect.
Let's nail it down to the following equipment as standard for any structure 1,500 to 3,000 sqft.
- 2 Wireless AP (Access Points)
- 1 Smart Managed Switch
- 1 Router with DHCP
Most of the time I can reuse your old desktop wireless device as the router or we can add one.
The price is really not an issue. Each AP I use costs about $65.00 and look like smoke detectors so they add a "Cool" factor to your home or office. Warehouses I use a TelCo rated AP that's about $114.
Each unit in open space covers the same and I have tested many AP's from the same point for increases. The types with external antennas will increase range but often give you a false feeling of speed.
The smart managed switch might cost about $100 but this is what I use to tag my devices based on AP connection.
Example: AP-01 that handles the streaming to my HD 1080 TV needs bandwidth priority over my tablet so I tag all packets so the switch knows what device gets a bit more push when it comes to wait time. It's all so fast you might never notice but when you do, you want your tablet to stall a millisecond not your HD TV.
Let's get Surveying.
Apps you need installed in your tablet or your phone.
- KaIBits software Network Signal Info (WLAN Signal dBm measurements.
- OpenSignal Wi-Fi dBm measurement
- OOKLA Speedtest
- MetaGeek inSSIDer signal measurements in motion / graphical. (optional)
Sight Survey Process
- Draw or sketch out a general map of your home, office or warehouse.
We will be noting the -dBm measurements in each location.
- Mount the AP on the ceiling as close to the center of the building or space as possible.
- Measure directly under the AP and note that point.
- Measure out 10 to 15 feet and make another note.
We need to identify how your antenna inside the AP covers.
You should do a 15ft circular walk around the AP to identify any weak antenna fields.
- Next we measure 1 wall obstruction and / or 25 feet from the AP.
Note the measurements. You don't need to be 25ft by measurement just general. But don't kid or lie to yourself to make your AP look better. It is what it is and I'm going to help you make your WiFi PERFECT!
- Next move to 50' and repeat at 75'.
- Depending on how large your space is I want the last measure on all exterier walls but from the inside. Measure every 10ft of your outside walls from the inside.
- Go outside your home or office and measure the signal 5 to 10 feet from the outside wall away from windows that are in direct line of the AP.
- Increase your distance in areas that you use outside as a patio or porch.
- Stop your survey when you are below (or above) -78dBm in any signal measurement.
Once you have your map you can either take a picture of it and send it to me via the portal.mysmallcloud.com service ticket system or by email. My service account at my small cloud . com.
The -42 to -55 dBm range is your center points and your -55 to -65dBm are your outer circles of signal.
If you draw a circle using a string and pencil showing your 0 to -65dBm points you can move the center point around to see where you need to mount your AP.
You may need to mount more than one AP which is standard in most all homes I have surveyed. You can have overlap of signal because we will be setting the channels or frequencies to work with overlapping singles. We can even device the networks by different SSID's but that's in select cases. I typically use a single SSID and Passphrase so the devices can roam from one AP to the Next based on Signal strength at the time. Some drawbacks are in those overlapping areas. I'll give you some good processes to handle this type of issue.
Once you have all your AP locations mapped let's make sure we can mount them within a few feet of your determined locations.
I like to use POE or Power over Ethernet devices because it makes it a bit easier to run a single network cable that handles data and power. But due to costs most of the newer AP's are AC adapters which makes it a bit more of an installation than just a simple mounting. In fact, the smoke detector type of AP's come with 4 foot cords on the AC adapter. I found this to be poor product design because most all ceiling start at 8' in height. I use Zip cord or 24gauge low power low voltage cord to extend the cable length to reach the first outlet. I try to go with the Ethernet cable but in most cases that's not an option.
With all your AP's mounted it's time to repeat the survey and measure your success in dBm. Remember, you're only fooling yourself if you say, "That's good enough". The time you need full bandwidth and look for the signal that's wasn't there when you had your tools out the only person to blame for poor wireless installs is yourself or that technician that I didn't train.
That's it for the AP survey, easy if you ask me. But it's not done, you now need to mount the equipment and start measurements again so you know the coverage is perfect like I promised.
If you like HDTV video streaming or plan on using a DLNA server to distribute all your purchased digital media to your home or office connected devices we need to setup a managed switch to make sure your giving bandwidth to the bandwidth hogs and enough for the others so they don't even notice a reduced transfer rate.
We'll do all of the following LAN tests between fixed hard drive devices of equal transfer rates.
Example: Transfer from two computers that offer 3Gb/s or 6Gb/s not IDE devices that are closer to 50Mb/s. We need to flood large files over the LAN to multiple wireless devices to seriously measure the sustained transfer rates.
In English, we need to know if everyone in your home or office can stream what they need to stream without taking down your LAN network or having people complain about speed issues or buffering.
Check back here for the Managed Network Configurations and Design.
Hope my information has helped you setup a better wireless network.