campus network scheme

davepenney · 03-24-2005

I plan to hack the MN-710
(http://forums.netstumbler.com/showthread.php?t=11051)
to add an extenal antenna, however

I need to run a pigtail for about 10-15 meters along the ground tucked just under the grass, so that i can reach round the side of the building and then situate my antenna (hidden in a bush). At this same point someone three floors above me uses a can type antenna, and recieves a medium signal.

Will I be able to recieve a signal if I use low loss RG58 50 ohm Cable such as

(http://www.maplin.co.uk/Module.aspx?...ldID=&doy=24m3)

thanks for any advice

theprez98 · 03-24-2005

Why do you call what you're doing a "scheme"?

Why do you have to hide your antenna?

If what you're doing is legal, you shouldn't have to hide anything...

What does this have to do with NS?

Standby...

The Others · 03-24-2005

In complete agreement with the post above, I would also like to point out one thing... The point of hacking that Microsoft adapter is that it is a USB adapter. USB cables have surprisingly less loss than microwave cables. Think it through...

davepenney · 03-24-2005

scheme, plan, method, idea, proposal, design

It’s not illegal in anyway since the wireless network is there for everyone in my halls to use, however i just don't live on the right side of the building.
I will have to hide the pigtail and antenna since along both side of the building run footpaths to the rest of the 3000 student housing, which means a lots of pissed people walk passed my window, maybe unlikely maybe not, but if I see a wire coming out of someone's window and disappearing into the ground i would probably have to investigate especially if i had a couple of drinks!

I thought this was a forum for all things wifi related, since all my searches and antenna designs usually lead to some part of this forum.

Sorry if I have posted in the wrong place.

davepenney · 03-24-2005

Quote:

Originally Posted by The Others

In complete agreement with the post above, I would also like to point out one thing... The point of hacking that Microsoft adapter is that it is a USB adapter. USB cables have surprisingly less loss than microwave cables. Think it through...

good point! always assumed it needed power supply aswell, but if its powered by the usb...

although maybe more likely to get stolen than a tin can

The Others · 03-24-2005

I'd sugest you buy your mate upstairs a WRT54G or similar, plug his cantenna into that and put it into client mode. I would have thought it would be easier to run CAT5 from his window to yours rather then placing stuff outside. As someone who has enjoyed the pleasures of university residences, I can understand why you may not want to make your scheme too obvious.

davepenney · 03-24-2005

Will probably have to stick with putting something outside, as the building manager gets a bit funny with wires going from people windows accross distance. I heard they stopped someone's private network when someone did that last year, there reason was that the CAT5 cable interfered with the fire alarm system...?

I think I will do the mod, then construct a watertight box and either paint on camouflage, or put the box underground. Then the long usb cable can just be tucked under the grass along the side of the building back to my room.

cheers for the ideas

davepenney · 03-24-2005

just read max length for usb 2.0 is 5 meters.... just when i thought i had sorted it out

The Others · 03-24-2005

Quote:

Originally Posted by davepenney

just read max length for usb 2.0 is 5 meters.... just when i thought i had sorted it out

Nah, a USB adapter doesn't draw much power, you can get away with longer cables:

http://forums.netstumbler.com/showth...=usb+parabolic

Airstreamer · 03-24-2005

Quote:

Originally Posted by The Others

Nah, a USB adapter doesn't draw much power, you can get away with longer cables:

http://forums.netstumbler.com/showth...=usb+parabolic

USB2 @ 480mb/s is where the problems lie with the length, I believe. At slower data rates you should be able to pull it off. (And if the device on the end doesn't pull much in the way of current from the pc.)

Maybe you should look into the fake rocks like they use to cover up the small satellite dishes?

Steve

Scruge · 03-26-2005

Quote:

Originally Posted by davepenney

just read max length for usb 2.0 is 5 meters.... just when i thought i had sorted it out

I've seen this on USB cable packaging as well. USB 2 is 5 meters and USB 1 is 3 meters max. Been meaning to explore the facts behind the lengths. I've been curious as to how a hub factors into the length.

streaker69 · 03-26-2005

Quote:

Originally Posted by Scruge

I've seen this on USB cable packaging as well. USB 2 is 5 meters and USB 1 is 3 meters max. Been meaning to explore the facts behind the lengths. I've been curious as to how a hub factors into the length.

It would depend upon if the USB hub is a Bus powered hub or a self powered hub.

Scruge · 03-28-2005

Quote:

Originally Posted by streaker69

It would depend upon if the USB hub is a Bus powered hub or a self powered hub.

hmmm, I assumed it was function of signal propagation, provided the USB device was self powered.
Went ahead and plowed through the USB 1.1 specs, 7.1.19 addresses Maximum end-to-end delays http://www.poweredusb.com/pdf/usb11.pdf. From the looks of the spec, it appears hubs are allowed a 70ns max delay and USB devices (functions) are allowed 30ns. Assuming a signal propagation of .3 meters per nanosecond / 2 (for round trip) x 70ns = 10.5 meters max (assuming a 0 ns turnaround delay). Then when you factor in a max 44ns hub delays 7.3.2 table 7-8 your are left with only 26ns for cable. Which works out to be approx 3.9 meters or 3 meters after you factor tolerances.

Without looking at the USB2 specs, I gather they probably have faster signal processing and shorter turnaround requirements which allows for a greater length of cable.

davepenney · 04-01-2005

just got 3 x 5m cheap ugly usb extension cable, connected them up and it works fine! no difference when using 15m or 1m, the computer recognises the adapter and doesn't loose it.

Scruge · 04-01-2005

Quote:

Originally Posted by davepenney

just got 3 x 5m cheap ugly usb extension cable, connected them up and it works fine! no difference when using 15m or 1m, the computer recognises the adapter and doesn't loose it.

Great! Your equipment must have been designed well, which is why you're going further. The USB specs only address the minimun requirements.

03-24-2005	#1 (permalink)
davepenney Registered Member Join Date: Mar 2005 Posts: 6	campus network scheme I plan to hack the MN-710 (http://forums.netstumbler.com/showthread.php?t=11051) to add an extenal antenna, however I need to run a pigtail for about 10-15 meters along the ground tucked just under the grass, so that i can reach round the side of the building and then situate my antenna (hidden in a bush). At this same point someone three floors above me uses a can type antenna, and recieves a medium signal. Will I be able to recieve a signal if I use low loss RG58 50 ohm Cable such as (http://www.maplin.co.uk/Module.aspx?...ldID=&doy=24m3) thanks for any advice

03-24-2005	#2 (permalink)
theprez98 SpoonfeederExtraordinaire Join Date: Jan 2005 Location: Maryland Posts: 3,709	Why do you call what you're doing a "scheme"? Why do you have to hide your antenna? If what you're doing is legal, you shouldn't have to hide anything... What does this have to do with NS? Standby... Last edited by theprez98 : 03-24-2005 at 08:36 AM.

03-24-2005	#3 (permalink)
The Others PeaceDriver Join Date: Apr 2002 Location: Dos Palabras, Mandoras Posts: 2,920	In complete agreement with the post above, I would also like to point out one thing... The point of hacking that Microsoft adapter is that it is a USB adapter. USB cables have surprisingly less loss than microwave cables. Think it through... __________________ all good ends all ?u=273

03-24-2005	#6 (permalink)
The Others PeaceDriver Join Date: Apr 2002 Location: Dos Palabras, Mandoras Posts: 2,920	I'd sugest you buy your mate upstairs a WRT54G or similar, plug his cantenna into that and put it into client mode. I would have thought it would be easier to run CAT5 from his window to yours rather then placing stuff outside. As someone who has enjoyed the pleasures of university residences, I can understand why you may not want to make your scheme too obvious. __________________ all good ends all ?u=273

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03-24-2005	#4 (permalink)
davepenney Registered Member Join Date: Mar 2005 Posts: 6	scheme, plan, method, idea, proposal, design It’s not illegal in anyway since the wireless network is there for everyone in my halls to use, however i just don't live on the right side of the building. I will have to hide the pigtail and antenna since along both side of the building run footpaths to the rest of the 3000 student housing, which means a lots of pissed people walk passed my window, maybe unlikely maybe not, but if I see a wire coming out of someone's window and disappearing into the ground i would probably have to investigate especially if i had a couple of drinks! I thought this was a forum for all things wifi related, since all my searches and antenna designs usually lead to some part of this forum. Sorry if I have posted in the wrong place.

03-24-2005	#7 (permalink)
davepenney Registered Member Join Date: Mar 2005 Posts: 6	Will probably have to stick with putting something outside, as the building manager gets a bit funny with wires going from people windows accross distance. I heard they stopped someone's private network when someone did that last year, there reason was that the CAT5 cable interfered with the fire alarm system...? I think I will do the mod, then construct a watertight box and either paint on camouflage, or put the box underground. Then the long usb cable can just be tucked under the grass along the side of the building back to my room. cheers for the ideas

03-24-2005	#8 (permalink)
davepenney Registered Member Join Date: Mar 2005 Posts: 6	just read max length for usb 2.0 is 5 meters.... just when i thought i had sorted it out

04-01-2005	#14 (permalink)
davepenney Registered Member Join Date: Mar 2005 Posts: 6	just got 3 x 5m cheap ugly usb extension cable, connected them up and it works fine! no difference when using 15m or 1m, the computer recognises the adapter and doesn't loose it.