USB cable impedance / burnt wifi usb adapter :S

[Calchaqui]

Hello guys and sorry but i cant short it and i really need your insight:
Had a big wifi parabolic antenna (24dbi) connected with the default 1 feet 50ohm to a TP-LINK USB wifi adapter 7200-ND, and then a custom made USB extension (26 FEET, a little more than max. spec) that i build using standard speaker wire for the power lines , data+ data- usb lines, each pair homemade shielded with shield grounded to my house, host's edge ends in a Y-shaped to drain a few more mA. Tested with a pendrive, evrething seems ok with mobo's rear ports, pannels ports make crazy things and/or did not recognize. USB wifi adapter works great 100% signal for 1 month than, starts to taking too long to initializing USB controllers at boot up, a week later begins to disconnect, and do not detect any wireless network at all, than it works ok. Going bad again, precious 100% signal streght is now at 20%, tried feeding it with a external 5v PSU, but nothing happens and windows take it but not wireless network detected at all, dead. Here in my country such entry level adapter cost me almost 7 dinners, so it's too costly for me. I need to know if:
1)Way too big antenna toasted the wifi adapter
2)It died because of luck.
3)My homemade usb extension with such huge speaker wires do not follow the 90ohms specification for USB bus signaling and it does reflect signal backward and burnt the wifi chipset . And/or my protective grounded-shield along the wires is a destructive one?

[Mad_Professor]

Re: USB cable impedance / burnt wifi usb adapter :S

No, your antenna didn't burn out your usb wi-fi adapter it's only got 100 milliwatt power. An antenna only amplifies the range which improves signal and reduces noise. More power from your transmitter (wi-fi card/radio), greater the range, less noise, better signal.

Probably what happen is there's too much noise on your speaker wire being used as data cable which is causing the devices on both ends to lose handshake and synchronization which then the computer goes to a fail-safe setting forcing it to link up at usb 1.0 specifications causing slow performance.
The fact that you're using speaker wire and have exceeded length specifications of 16 feet is probably and most likely your problem.

It's also possible that you blew the fuse on your usb ports.

Test your usb ports with another device, example: keyboard/mouse, USB audio, external hard-drive.

And...

Either get two proper usb cables and usb hub, or an active usb extension cable, or an USB-Over-Cat5 adapters, or a wireless AP/BRIDGE device.

Or simply move the wi-fi card to 15 feet of your computer.

Also try leaving the computer off with the wi-fi card disconnected for about 30 minutes, that way any faults on the motherboard will clear and resume normal function.

[Calchaqui]

Re: USB cable impedance / burnt wifi usb adapter :S

Thank you

Probably what happen is there's too much noise on your speaker wire being used as data cable which is causing the devices on both ends to lose handshake and synchronization which then the computer goes to a fail-safe setting forcing it to link up at usb 1.0 specifications causing slow performance.

How can i test the line's noise? i've ran I/O software tester and works great with a card reader, but plug in and plug out stuff, a SD card died :S.

Either get two proper usb cables and usb hub, or an active usb extension cable, or an USB-Over-Cat5 adapters, or a wireless AP/BRIDGE device.

I thought that using custom ""quality"" thick speaker wire would turn to be a way better data line that those chinese hairy-copper usb extension. Could i replace the speaker wire data line by using 2 standard coaxial tv cable (75 ohms) ? or it will be worse than the speaker wires?

[Th3_uN1Qu3]

Re: USB cable impedance / burnt wifi usb adapter :S

It isn't the quality of the wire - it's the construction and length. Cable thickness only matters for the power and ground lines. The datalines can be as thin as a hair - no significant current flows thru them.

On the other hand, what IS important is that the data lines are twisted pair so any noise they pick up cancels itself out. USB uses differential signaling on the data lines.

Try using Ethernet cable for the extension. For power and ground twist 2 or 3 wires together, for the data lines use one of the twisted pairs as they come in the cable.

[stj]

Re: USB cable impedance / burnt wifi usb adapter :S

you wont get long usb cables to work no matter what you try - volt drop & parasitic antenna effect will mess it up.

there are 2 options.
1: use a short cable to a raspbery-pi on the back of the dish, and then run ethernet over STP cable.
2: use an ethernet based device like a TP-Link WA5110G

i have the 5110g and it's really good, 400mw output and POE so you just need a waterproof box and the ethernet cable.

[budm]

Re: USB cable impedance / burnt wifi usb adapter :S

Active extender:
http://www.monoprice.com/Product?c_i...seq=1&format=2

[stj]

Re: USB cable impedance / burnt wifi usb adapter :S

probably wouldnt work.

btw, it occurs to me that the reason for using usb may be that your using AircrackNG or similar.
in that case, forget the 5110g.
but the pi could run it and be controlled via SSH.

[budm]

Re: USB cable impedance / burnt wifi usb adapter :S

Is this what you are using?
http://www.tp-link.com/En/products/d...el=TL-WN7200ND

[stj]

Re: USB cable impedance / burnt wifi usb adapter :S

that's the one he listed, and if it's the one i think it is, it's capable of something like 4x the legal power level

[Calchaqui]

Re: USB cable impedance / burnt wifi usb adapter :S

It is the only one that i could get to work with my 24dbi antenna, since plug the big antenna in a standard PCI wifi card I get worse signal than with the default 3dbi small one. I thought that maybe such a difference of impedance between the adapter and antenna could make this one to act like a mirrow and reflect the Signal Transmission back to the usb adapter and that way it got toasted :S could that be possible?

[stj]

Re: USB cable impedance / burnt wifi usb adapter :S

you should put the antenna on the lnb ring, and the radio module out of the way of the reflected signal.

as for the pci card, what a lot of sellers dont tell you is the cable loss per meter is huge - upto 3db per meter even with good cable.

btw, is the parabolic a solid sat dish? because if it is then the gain could be a hell of a lot more than 24db

the other thing to remember is polarisation.
you have a very selective antenna, if your target is using a horizontal antenna then you must too - equally if the target is vertical you must be vertical or you wont get a signal.