[master4g]

We need to connect two buildings about 30 ft apart, but we are unable to run a wire because of what comes inbetween (staircase and elevator). How would you guys suggest bridging the two buildings? we need to be able to get speeds of 50mbits with this bridge.

we looked into powerline ethernet, but from what i read, its too slow

we thought about wifi, but i am concerned about interferences like microwave (these are two apartment buildings), 2.4ghz cordless phones, maybe the elevator?.. and anything else. the distance is very small ..do you guys think wifi would work?

my goal is to get it done for under $75, even if we have to get used parts. any suggestions?

thanks

[JohnWill]

Well, $75 puts a limit on what you can do realistically.

I'd be looking at an 802.11n setup with directional antennas for maximum reliability, since that will give you plenty of signal strength to overcome most other 2.4ghz interference. I'm assuming you have direct line-of-sight between the two buildings. I'd also use external antennas to have no barriers of any kind between the two units. Failing that, at least put the antennas in facing Windows, glass is more transparent than brick or concrete to WiFi communications.

You'd need a wireless bridge and a router or WAP and the antennas.

[metalmadness]

Originally Posted by JohnWill

Well, $75 puts a limit on what you can do realistically.

I'd be looking at an 802.11n setup with directional antennas for maximum reliability, since that will give you plenty of signal strength to overcome most other 2.4ghz interference. I'm assuming you have direct line-of-sight between the two buildings. I'd also use external antennas to have no barriers of any kind between the two units. Failing that, at least put the antennas in facing Windows, glass is more transparent than brick or concrete to WiFi communications.

You'd need a wireless bridge and a router or WAP and the antennas.

All the way with 802.11n, now uses both the 2.4 + 5 GHz bandwidth! It was officially standardized a few weeks ago (correct me if i'm wrong). $75 is not that bad, if you're gunning for the cheaper models. I've done a Google search for the router prices, and many of them fall on the $100-and-below category, lest you use the "enterprise" models.

Not really sure on how would master4g setup his network topology, but I'd probably recommend putting a main AP and use a router or two to serve as a wireless repeater. In my scenario, I have a Linksys WRT400N setup as the main AP, and a WRT300N mounted inside a small closet on the second floor of the house, serving as a wireless repeater (using DD-WRT custom firmware). Before putting that repeater in the second floor, I was getting bad reception because of the furnace blocking the path from the WRT300N. Now it's all stable

[JohnWill]

Well, since I figure he has networks on both sides of the fence here, I figured a wireless bridge and a WAP ( or router configured as a WAP ) would be the most straightforward solution. I don't see buying those two items and perhaps hi-gain antennas as well, for anything close to $75 total.

Of course, you can cut the price with 802.11g, but not that much, and you give up the bandwidth, which may be key here.

[master4g]

the line of sight is direct, but the elevator is on the side not to far away, do you guys think it would interfere with the wifi if someone summons the elevator?

[master4g]

let me give you guys some more background, maybe it will help bring up some more solutions.

we have a network with 7 hubs, all connected with about 12 apartments and providing internet. the internet goes from our central location with the router to each building via cat5 except the last building which i guess is too far for cat5 so the person who actuallly set this up decided to go with fiber optic. All wiring is under ground.

Now,we have been having problems with our network so i decided to check things out and found out that the buildings have 10mbit hubs! (but we have a 50mbit internet connection) . so time to upgrade to 100mbit switches.

the problem is that there is that the person used two 3com SuperStack II PS Hub 40 hubs with "3com TCVR Fiber module" and ran a fiber optic cable to connect the remote building to the rest of the network, but im guessing that changing the hub to this building will cost way more because i need some sort of fiber to ethernet converters.

The good news is that the second to last building isnt that far from the last one so i can just BRidge from the second to last swtich to the last one (going underground would cost too much)



what do you guys think? do you guys think i can use the existing undergound fiber optic cable by getting some sort of fiber to ethernet converter for cheaper than the wifi solution? we dont mind buying used form ebay or wherever.

[JohnWill]

Actually, Ethernet to fiber converters would probably still be the best solution. You'll need to find out exactly what type of fiber is used, but the converters will probably be around $100-150 for each end. This would obviously be the best solution.

I am curious, are these freestanding buildings? If they pulled the fiber to the far building, couldn't you pull a CAT5 cable? You can run Ethernet 100 meters with no issues, and usually get away with 150 meters easily for 100mbit.

[Frank4d]

You mentioned in your first post that the buildings are 30 feet apart and a staircase and elevators are obstacles.

But keep in mind, a CAT5 cable doesn't need to be run point to point. It can jog left 50 feet, up 10 feet, back 15 feet, back down 10 feet,right 100 feet, etc... finally reaching its intended destination (you get the idea). As long as the total run is less than 328 feet.

[master4g]

regarding the previous two posts:

@frank- we thought of that, but its outdoor and the way around to such a close building would be surprisingly long

@JohnWill- I have absolutely no experience with fiber optic. Can you give me some idea of how i can figure out how to identify which type of cable is being used.

I found this on ebay, its 25$ with shipping...do you think it will do the job?

http://cgi.ebay.com/Signamax-Gigabit...#ht_500wt_1182

http://www.signamax.com/index.php?typ=SXE&showid=368

[JohnWill]

Here's the page with the specification sheet, see if the specs for the fiber compatibility match the existing units you're using.

http://www.signamax.com/index.php?typ=SXE&showid=368

FIBER INTERFACE, MULTIMODE PN 065-1194 & 065-1195:
Type: Laser Diode
Wavelength: 850 nm nominal.
Maximum Output: - 4.0 dBm
Minimum Output Power: - 9.5 dBm
Sensitivity: -13.5 dBm
Maximum Input Power: - 13.5 dBm
Link Power Budget: 4.0 dB

[zx10guy]

The Signamax will do the job. The catch is going to be whether the devices are on the up and up from the seller. I find it extremely hard to believe that these fiber transceivers/media converters are being sold for $25 new. Those things run for about $250 or so. Even with discounting, I find it hard to believe the $25 price. Keep in mind this transceiver will only do GigE copper. It will not work with 10/100 Mbit copper. I've used plenty of Signamax transceivers and they've been very good. They do run hot so be aware of this.

What you have to determine on your existing fiber is the connector end. The one you've linked to uses SC fiber connectors.



The other type based on the vintage of when your cable was probably installed can also be this...ST



There are other types of fiber ends such as LC and MTRJ. But I doubt you have those connectors.

A particular fiber is also purchased for the distance involved. Typically you would see fiber listed as either multi mode (62.5 micron) or single mode (50 micron.) I forget the maximum lengths for either. You can find this information on the jacket of the fiber.

I agree with John. You'll be better off using the fiber there already. I would also ditch the transceiver idea and buy a switch with the appropriate ports on it. If you're willing to go used, you can find a myriad of switches out there which don't necessarily have to be managed to give you both fiber uplink capability and copper. You'll probably looking at 10/100 copper switches with a couple of GigE fiber uplinks. The type of uplink port you get depends on the fiber you're using and the distance of the fiber from end to end. You're looking at probably GBIC versus an SFP which are for LC type fiber ends.

[master4g]

thanks guys for the tips, especially the pics. some of the terms flew over my head as i am not familiar with fiber optic. Im not even qualifed for any of this networking stuff, but im trying to make it work out. The non-profit lab i work for doesn't have enough money to get some experts to come get the job done, or to buy expensive parts. I was barely able to get approval to get the money for this cheap project (trying to go for <$75).

Anyways, the cables we are running look like the second picture you attached. ST i guess. The distance we are looking at isn't too far, just barely longer than the max CAT5... so probably around 400ft.

So im assuming that linked converter wont work, any suggestions? i did a quick search and found there is a ST to SC coupler... do you guys think that would work with the above linked ethernet to fiber converter.?
http://cgi.ebay.com/NEW-StarTech-com...ht_3047wt_1069


or what about a cable like this: http://cgi.ebay.com/3M-SC-2-ST-DMM-M...ht_4712wt_1026

allowing me this : ethernet----->signamax converter------>cable above------->attaching to ST cable------->cable above------>signamax converter------>ethernet?

[zx10guy]

The cheapest way to make this work is to use the coupler in the first link. I've never used a SC to ST coupler. I have used SC to SC and LC to LC couplers. Oh and the odd occassional ST to ST coupler. From my experience, the SC to SC and ST to ST couplers work well. The LC to LCs are a mix bag. The issue you're going to have is to ensure the fiber ends are lined up adequately to allow beam transfer from cable to cable. So going this route you'll still need to buy a short run of SC to SC cable. The SC to SC cable would go into the Signamax on one end and into the coupler on the other. The existing ST fiber you have will then connec to the coupler.

A better way in my mind is to use the cable you linked above. Plug the SC end into the Signamax and then the ST end into this coupler:

http://www.cablestogo.com/product.as...=111&sku=10552

The existing ST fiber you have will mate to the other end of the coupler. This will allow coupling of similar ends instead of having coupling dis-similar terminations.

[zx10guy]

Oh and I forgot one other thing.

With fiber, there is a transmit and receive topology. Make sure the fiber that connects to the transmit side of one Signamax goes into the receive side of the other....and vice versa. With the ST cables, it's real easy to mix this up. With SC it's less likely to happen.

And you may want to get a quality fiber cable. As it becomes a real headache to troubleshoot connection issues with fiber unless you have an actual tester. I've had situations where a fresh cable sourced from a reputable company, Black Box, be bad right out of the box. The problem was compounded that I got a link light confirmation on both ends but was getting poor data flow through the cable. I replaced the cable and that resolved the problem.

Also, fiber requires special handling. DO NOT BEND, CRUSH, CRIMP THE CABLE. If you loop the cable to tuck away excess make sure any bends have a large enough radius.

[master4g]

thanks again

fortunately, in our main internet closet (which houses the head hub and the internet modem) there is a female connection for the fiber st on the Rack so i think i can skip buying one of thuse female-female connector as linked and just unplug the existing ST and plug in the SC-ST cable from the signamax converter.

Also, what would be your main concern about that seller on ebay, he has 100% feedback and the boxes seem to be new so Im thinking about going for it with him... what do you think?