My Wi-Fi doesnt work!

Understanding Wi-Fi problems is straightforward if you think about the Physics!

Look at the drawing:


There is a laptop using Wi-Fi to connect to a router and then to the internet.

The direct signal (blue arrow) will give a great signal.

Now remember that you have lots of computers and the router has to transmit in every direction, not just direct to your PC.

If somebody puts a reflective item close by, for instance a filing cabinet, it might cause a second reflected signal (Orange arrow) that is also received by the PC.
The reflection travels further (two sides of a triangle) and so arrives later.

If you look at the graph, you can see that the later reflected signal is going upwards (or more positive) when the direct signal is going downwards (or more negative).

The two interfere to make a common
weaker signal at the PC.

Wi-Fi can bounce off all sorts of surfaces. These include energy efficient glass, cookers, radiators, filing cabinets, smooth walls and even ponds or fish tanks!

The important thing to remember is that Reflections = Poor Wi-Fi!

Now consider that the reflection could be your neighbours Wi-Fi! Just by having two routers in adjacent buildings you can cause poor Wi-Fi!

The solutions are often simple. Turn down power (not turn it up). This stops reflections. It also stops you reaching the neighbours.

Get high quality routers and Wi-Fi.

Wire a Wi-Fi unit in each important area (office, front room etc.) and keep power low. Short distances with low power is better than a central transmitter with lots of power!

Of course there is far more to the physics and there can be lots more questions;

  • What Frequency band (5G or 2.4G)?
  • Will the phones and Microwave interfere?
  • Will the antenna focus the power in my office or the adjacent one?

Don’t be frightened, you simply need to know that Wi-Fi needs setting up properly if you want reliability.

Andisa have invested in training and equipment so that we can measure and fix your Wireless problems!

The process is simple and normally involves a coffee with one of our engineers. 

How can I move from room to room without needing to reconnect all the time?WiFi networks are identified by a name or SSID. Computers try to connect to the transmitter with the strongest signal strength.
If two adjacent WiFi networks have the same name then a computer will get confused!
This means that its more difficult to add multiple WiFi units and still be able to move from room to room.
In a public building with lots of rooms this is more complex.

The solwap121-3ution is to install a WiFI transmitter that is designed to "Cluster". Clustering means that several WiFi Access points are installed and configured so they monitor each other. As one causes interference it is instructed to reduce its power. If a blind spot is detected the the adjacent ransmitters increase power.
As a computer Roams, or moves from one room to another, the access points automatically reconfigure so the SSID can be followed.
The end result is a network where people can move from room to room without loosing signal!
Clustering Access points start at £120. Call 01423290029 and speak to Andy to discuss.

Can I link buildings together using WiFi?rbsxtg-5hpacdkit

Many businesses are expanding into adjacent buildings. Some are spread across a wide area often across fields and want to link remote buildings. With recent inovations it is possible to link buildings using WiFi.

There are many challenges;
Distance; The further you try to link the more powerfull a transmitter you need. The law sets the maximum transmission power but you can compensate with a high gain antenna. We have tested links over 20km and successfully achieved speeds in excess of 60Mb/s! To do this reliably you need a transmitter like the Mikrotik SXT range with 16dB antenna.mikrotik logo

Cost; There are models designed to give much higher rates or work over much longer distances however the MikroTik SXT 5AC is affordable and full of features. The SXT range starts at £121 each including a basic configuration.

Optimisation; The built in router means that you can optimise the link so that only necessary traffic is sent across the link.

Management; It has built in network management, VLAN and DHCP settings so the computers at the remote sites can be automatically configured and maanged.

Simplicity; Clearly you would be better to use the services of a specialist such as Andisa to install the system but there is also a built in web page that allows you to set a basic system up yourself.

Call 01423290029 and speak to Andy to discuss.


Example One.
We have a 20km link already installed in a remote valley in Nepal. It gives a reliable 65Mb/s link between a central internet feed and a school.
Previously the network was limited by the amount of unwanted braodcast traffic. In fact up to 60% of the traffic was wasted.
We have installed the MikroTik devices with a fully router network. The management links are separated by VLAN so that the devices can be monitored and reconfigured even with users on the system.
The overall speed increase was 30 fold! Now students are able to browse the internet easily. As the system grows we are adding queues, to split the bandwidth between types of traffic. Windows updates will happen slowly without stopping other usres. Email will be transmitted in a controlled way whilst the browsing experience will get the most priority!

Example Two.

We recently installed Ubiquiti Wifi devices into two houses. The original problem was the same in both places. Lots of transmitters to cope with thick walls. People couldnt move reliably from one room to another.
The new Access Points (three in each houseset to minimum power)  talk to each other over the wired connection and make sure that computers connect to the closest Access point as they are moved from room to room. 
There is now only one set of credentials even though the users can now roam properly. Previously there were different credentials for each area of the house.

The outcome is that the house owner  can now view security cameras reliably from anywhere in teh house and feels confident to answer the door.