As shown in Can you Hear Me Now? we have installed a WiFi repeater aboard Viking Star. The primary purpose of this repeater is to reach out and connect to a distant WiFi station, one MUCH further than could be done using just our laptops themselves. And the 2nd purpose of this 'repeater' is to allow more than one computer to share a distant connection.
There are several ways to get long distant WiFi connections, starting with external USB dongles-- often augmented by empty Pringles Cans or wire cooking colanders. Hey, don't laugh, they work rather well. Google up: "Poor Mans WiFi" and see what folks have done! More elaborate (and better range) systems use Ethernet-based external WiFi receivers, or even more elaborate repeater systems like we have here on Viking Star.
And there is also a wide range of prices, from as low as $15 for an external USB Dongle + Wire Basket, to approaching $1,000 for a proper repeater system like shown here.
But if you all know me, you know I did not pay $1,000 for our system. (And no one should, there are well-designed, pre-configured systems out there for under $400).
www.ubnt.com/bullet. These low cost devices are wonderful radios, featuring high power and good sensitivity, mounted in an all-weather case with Power-over-Ethernet -- so only one wire needs to be routed to the device. In the simplest form using one of these units, an antenna, some CAT-5 cable and a POE injector and you can be up an running on one computer for just a bit over $100. Add a simple router and you get the complete repeater system for under $150.
There are a few companies who will pre-bundle these kits for you, and to be honest I kind of like this one: www.wavewifi.com. For about $375 you get a complete kit with all the parts, including a router! One of the other reasons I like these folks is they have gone in and simplified the Bullet firmware, making it simple to setup and use this system. Almost all other 'kits' out there leave the default Ubiquit firmware in place, which can be a bit overwhelming. WaveWiFi has done a great job in simplifying everything. Another provider that gets a lot of good comments is: www.islandtimepc.com/marine_wifi.html. Their offering is the basic stuff, no extra firmware and is no different than what you could purchase independently - ala below. But it does all come at once, and they have some creative antenna mounting solutions as well. Starts at $250, more for different antenna mounts and optional router.
Now if you want to save some $$$, know a little about setting up IP routers and such, keep reading!
WiFi repeater used on Viking Star
- Bullet M2-HP, ala: www.invictuswireless.com/M2-HP....... $78
- 9dbi Omni-directional Antenna, ala: www.invictuswireless.com/24_9OD_p. . . . $43
- CAT-5 Patch Cable - long enough to match your installation
- 12v 'Router' of your choice (I used a Linksys WRT54G V5)
- PoE Injector - Easy way, or modify the Router (Free way - see below) $5 (?)
- 3M Supper88 Plastic Electricians tape
- 3M SCOTCH 2210 VINYL MASTIC Water-proof seal
And do NOT skimp on the Super88 plastic tape. It does cost more, but is well worth it. The 2210 Mastic is the key to making waterproof enclosure between the Bullet and the Antenna, as well as the Cat-5 cable. (And why I do not think the Titanium bullet is needed - its all going to get wrapped up anyway). It might be available at a Big-Box store, or mail order. It comes in 10' rolls for around $50, so unless you are going to do a LOT of these you might see if someone wants to go in with you. I ended up being able to purchase some by-the-foot at an electrical supply house.
Power to the Bullet! - The Easy Way
|Spend the $5 and get a PoE adapter, trust me!|
Power to the Bullet! - The Hard Way. . . .
Sadly, when I put this together these low cost PoE adapters were not available, so I modified the inside of the WRT54G to provide the PoE function. And even today it is a free solution!
|Remember, you need only to solder on one set of wires.|
Make sure to mark on the outside some way which of the RJ-45
connectors you soldered the wires to. (I used a Sharpie)
Connections to the WRT-54G
Making it Waterproof
- Use the Supper88 tape to make 'Courtesy Wrap's directly over the antenna connection and the place where the CAT-5 wire comes out the bottom. This is just a couple of turns of the tape which will aid in un-gunking things if (when) you need to open things up in the future for servicing Do not go wild on this, just a single layer a couple of tape widths wide is sufficient Some folks even put the tape on Backwards (sticky side out) to work even better.
- Using the SCOTT 2210 mastic to cover everything up. Starting about 2 inches above the top of the Bullet antenna connector to a couple of inches below the CAT-5 cable. It is a self fusing tape, pull it firm, make about 2 layers, and then mash it all together into a fused ball.
- Cover it all up with two wraps of the Super88 electrical tape. Making sure to go a bit higher on the antenna and the CAT-5 cable with each wrap.
Configuring the Router and Bullet
- Configure Bullet
- Configure Router
- Fine tune the Bullet
- Attach Bullet to external WiFi network.
- 192.168.1.1 = Linksys WRT54G
- 192.168.1.20 = Bullet
First Step: Configure the Bullet.
* Yes, I know the words Transmitter and Receiver are not being used properly here, but I though it might better explain things. The correct words are: Access Point and Station. And being truthful - Router is a word that is not totally correct when referring to the WRT54G, but it is in common usage. . .
- In Network Role, change the Network Setting setting to Router.
- In the WLAN section, change the DHCP address to something like I have. We will be moving everything away from the common 192.168.0.x or 192.168.1.x. Not doing so might make it more difficult to manage your new WiFi repeater when it is connected to an external network. You can pick lots of different addresses, just make sure it is one of the 'protected' local-only block of numbers. I selected to use 192.168.37.x for all my setups.
- In the LAN network section, put in a new IP Address, and then check all the NAT boxes as shown.
- Still in the LAN section, check the Enable DHCP box and fill in the appropriated start and end ranges. This is where we will pick up the DHCP and NAT functions we disabled in the WRT54G
Next step: Configuring the 'Router'
- Change the Local IP address to something unique within your new selected block of addresses. (I selected 192.168.37.6)
- Disable the DHCP server - the internal NAT server will automatically be disabled as well.
Fine tune the Bullet
Attach Bullet to external WiFi network.
Big Ears and Big Mouth
The repeater is doing the same thing. Using a more powerful transmitter in the Bullet, we have a much bigger mouth than the laptop, and the gain of the antenna gives better ears. But this is not always enough. One situation we have found where the repeater does not work very well is in a crowded city. When we were in Portland at the Blues Fest we were able to 'see' over 200 stations. But even though we were only a couple 100 yards from an access point we were not able to connect to it. I liken it to being at two sides of a room at a very crowded party. Even though we are yelling at each other (Big Mouths), and cupping our ears (Big Ears), there is just too much noise around to be able to effectively communicate. WiFi was designed to work at a range of 100' or so, and as such, when there are a LOT of stations in place there is really no method for coordinating all that yelling . . . . of course using a highly directioned antenna would solve this. But for us, we just grab the laptops and walk up to the coffee shop.
Why LAN and not WAN connector?Someone asked me why I connected the Bullet to the LAN port and moved the NAT and DHCP functions from the WRT54G to the Bullet, as opposed to the more 'traditional' setup of plugging the Bullet into the WAN port. IIRC, I had tried several configurations (hence the PoE wires to the WAN and LAN port) and decided on this approach for two reasons:
- Using the WAN port I could not 'see' the bullet at its default 192.168.1.20 address. This was because the WRT54G had reserved the whole 192.168.1.x address space for its 'local' use and would not pass out anything in that space out via the WAN port. Moving the WRT54G to a different address space (ala 192.168.0.x) solved this problem.
- But - with the NAT not being enabled in the Bullet I found that if I attached to a remote WiFi network which had also been setup in the 192.168.1.x address space, I could no longer gain access to the bullets setup and management screen as the remote WiFi had assigned a new address to the bullet. I COULD have hard-coded its address, but that would raise the potential of address conflict. This was a pain, and required 'remote resetting' the bullet to regain control.
Final Thought - the other way to remotely reset the Bullet
I like to use these 'power' Bridge Rectifiers for things like Voltage Dropping They are relatively low cost (as long as you do not purchase them at Radio Shack!). But mostly I like them because due to their physical mass: they have a sufficient level of heat-dissipation capability all by them self without the need to extra heat-sinks. (For this application! We are only drawing perhaps 1-2Amps MAX).
Just run the battery power to the '-' terminal on the bridge-rectifier, and then the '+' terminal to the WRT54G. We will not use the '~' terminals in this application. You can even clip those off if you want, but do make sure to cover them with some electrical tape, to reduce the change of stray wires shorting.