Realistic Expectations of OmniBox and other WiFi Solutions

Sitting on your boat connected to the Internet, having free telephone with Skype and being online whenever you want is the dream that we had that brought us to develop the OmniBox.
The OmniBox has fullfilled our dream but may not fullfill you dream, so let me tell you why, so that you can have realistic expectations and understand whether the OmniBox, or any other solution will help you.
A basic requirement for a good WiFi connection is 2 way communication between the 2 devices. The Access Point (AP, Hot Spot or whatever you want to call it) and the OmniBox (or your computer's WiFi modem).
Without this 2 way communication it simply won't work.
Lets take a few example situations which are actually real and were contributed by our customers.

1. You are in the vicinity of tens of Access Points, most secured but a few unsecured showing signal strengths (RSSI) of -80 to -140dB. You want to get online, especially as these unsecured AP's will probably be free. You have a powerful OmniBox with 35.5 dB. Will this work? Probably not, why?
The low signal strength you are seeing is probably from residential WiFi routers that typically have a maximum of 70mW (18dB) transmit power through a maximum of a 5dBi antenna. The unit is indoors and the signal is attenuated by walls or you are picking it up through a door or window which means the signal will vary as you move around. So you don't have much to work with unless you can get really close. You are limited by the AP and there is little you can do about it. So you are trying to connect to an AP having 23dB transmit power in ideal conditions with an OmniBox that has 35.5dB. Remember, every 3dB doubles the power so the OmniBox is at least 12 times stronger!
Typically  the folks who leave their routers unsecured are not knowledgeable and have low cost and weak WiFi routers. If you can get close enough, have a line of sight and have a good WiFi modem in your computer you may even be able to communicate without the OmniBox as your WiFi modem probably is of similar strength to the AP.
So the dream of a free connection "borrowing" unsecured routers is unrealistic as well as probably being  illegal.
Also, don't waste time on signals with less than -70dB which is equivalent to a RSSI of 10 with a noise of -94dB. Even if you do connect, it will be very slow and flaky. The signal is so weak that even a very sensitive receiver will have difficulty separating the signal from the noise.

2. You anchor or moor in the vicinity of a marina. You get a pretty good signal from the marina's access point on your computer but cannot connect. You go ashore with your laptop and connect successfully. When you browse, a marina web page comes up asking for a user name and password. The marina sells or gives you a login and you are online!
You go back to the boat and try again. You manage to connect sometimes, but as the boat moves you disconnect. The connection is slow and you can't use Skype. But you have a good signal strength, whats wrong?
Simply, you are receiving well, but the AP is having difficulty hearing you. Every time the AP sends a packet, it waits for you to acknowledge. If you don't acknowledge it resends the package. So if you do connect, the connection will be slow and flaky. So how far can I be from the AP? Well, it depends on line of sight, whether you are on deck or below, how you are swinging on the mooring, the WiFi modem in the computer. In our experience, anywhere from less than a 100 feet to up to 1000 feet.
Will the OmniBox help here. Certainly! The OmniBox has about the same strength as a good external AP. Your limitation will really be only line of sight. You could be miles away and still have a reliable fast connection.

3. You are at a slip. The AP is 6 feet from your bow. You cannot connect via the OmniBox nor directly to this AP nor any other AP's at the marina. All the marina's AP's are on channel 6. Using the OmniBox you can connect to a weak unsecured AP where you have a slow connection, good enough for email but not Skype. The next day the Marina's AP's work fine, both directly and via the OmniBox. Why? Its hard to know exactly but firstly, having overlapping AP's on the same channel is not ideal. It appears that the marina's setup had a problem which someone resolved.

4. You connect to an unknown unsecured AP with the OmniBox that has a good signal strength but although it shows connected, you cannot browse or use the Internet. The AP happens to be called MAC_secured. You go ashore with the laptop where the signal strength is even higher and get the same results. There is no encryption yet you cannot get online! What happened? Well, it's likely that a savvy user has a powerful router that they probably use outside. They have probably chosen to setup the router without encryption so that they don't have to bother with keys, but have configured the router so that it will only communicate with devices with known MAC addresses. So can you use this AP? Only if you ask the owner to add your MAC address to his list. The MAC address of your OmniBox is conveniently listed on the labels, one on the lid and one inside the lid. Use MAC1. The AP's name is rather apt.

Conclusions

• Two way communications are required for a usable connection.
• Although you may think you are connected, you may not have Internet access dependent on signal strength, encryption and access control.
• If you are close to your AP with your laptop, have a good signal strength and still can't get Internet access, the Omnibox will not help. There is an access problem or an AP problem that needs to be resolved.
• If you are distant from an AP, have a receive signal greater than -70dB, your OmniBox will make access possible when your computer cannot connect.

Atheros Link Quality(SNR)/Signal level association table:

Link quality (RSSI)	Signal level (dBm)	Link quality (RSSI)	Signal level (dBm)	Link quality (RSSI)	Signal level (dBm)	Link quality (RSSI)	Signal level (dBm)
60 /94	-35	45 /94	-50	30 /94	-65	15 /94	-80
59 /94	-36	44 /94	-51	29 /94	-66	14 /94	-81
58 /94	-37	43 /94	-52	28 /94	-67	13 /94	-82
57 /94	-38	42 /94	-53	27 /94	-68	12 /94	-83
56 /94	-39	41 /94	-54	26 /94	-69	11 /94	-84
55 /94	-40	40 /94	-55	25 /94	-70	10 /94	-85
54 /94	-41	39 /94	-56	24 /94	-71	9 /94	-86
53 /94	-42	38 /94	-57	23 /94	-72	8 /94	-87
52 /94	-43	37 /94	-58	22 /94	-73	7 /94	-88
51 /94	-44	36 /94	-59	21 /94	-74	6 /94	-89
50 /94	-45	35 /94	-60	20 /94	-75	5 /94	-90
49 /94	-46	34 /94	-61	19 /94	-76	4 /94	-91
48 /94	-47	33 /94	-62	18 /94	-77	3 /94	-92
47 /94	-48	32 /94	-63	17 /94	-78	2 /94	-93
46 /94	-49	31 /94	-64	16 /94	-79	1 /94	-94