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USB WiFi Adapter Extension

Hi Everyone,

The project I want to do is to mount a USB WiFi adapter on the end of a satellite dish. I've already built a cantenna system but it suffers from not being able to have too long an antenna cable, so mounting it outside becomes problematic. I thought that simply focusing onto the internal antenna of a USB device may be a more practical way of going about it. I've jury rigged a simple test using a USB extension cable and it works impressively well but again suffers from the cable length issue, although I can get a longer length from a USB extension, it's still not long enough to reach to the outside mount. So my idea is to use an ethernet cable. Take the WiFi dongle apart and solder Data+ and Data- to one of the twisted pairs, on another twisted pair, I'll carry 24V (or 12V if I can get away with it) from a power supply at the computer end, then on the dish end, use a 7805 and a couple of caps to regulate down to a steady 5V which is connected to the power pins of the WiFi dongle. At the computer end, I then just make sure the -ve of the power supply is common to the ground of my pc and connect Data+ and Data- to a usb port, either with a plug or directly onto the motherboard header. I'm worried if the 5V data lines will degrade too much down the cable and if I'll need some kind of step up/step down mosfet arrangement at both ends. I know it's not a very expensive or complex thing to just build and try out, but it's always prudent to ask experts before switching on the soldering iron. So any advice or pointers on this would be appreciated :)

Many thanks
Mort
 

davenn

Moderator
. So my idea is to use an ethernet cable. Take the WiFi dongle apart and solder Data+ and Data- to one of the twisted pairs, on another twisted pair, I'll carry 24V (or 12V if I can get away with it) from a power supply at the computer end, then on the dish end, use a 7805 and a couple of caps to regulate down to a steady 5V which is connected to the power pins of the WiFi dongle. At the computer end,

that may solve the power supply voltage drop to the dongle but it isn't going to solve any voltage drop on the data lines. you are likely to end up with a well powered dongle that isn't getting any data or data that is severely degraded
So what are you really trying to achieve ? what is the need for a dish fed wifi system ?

Dave
 
Hi Everyone,

The project I want to do is to mount a USB WiFi adapter on the end of a satellite dish. I've already built a cantenna system but it suffers from not being able to have too long an antenna cable, so mounting it outside becomes problematic. I thought that simply focusing onto the internal antenna of a USB device may be a more practical way of going about it. I've jury rigged a simple test using a USB extension cable and it works impressively well but again suffers from the cable length issue, although I can get a longer length from a USB extension, it's still not long enough to reach to the outside mount. So my idea is to use an ethernet cable. Take the WiFi dongle apart and solder Data+ and Data- to one of the twisted pairs, on another twisted pair, I'll carry 24V (or 12V if I can get away with it) from a power supply at the computer end, then on the dish end, use a 7805 and a couple of caps to regulate down to a steady 5V which is connected to the power pins of the WiFi dongle. At the computer end, I then just make sure the -ve of the power supply is common to the ground of my pc and connect Data+ and Data- to a usb port, either with a plug or directly onto the motherboard header. I'm worried if the 5V data lines will degrade too much down the cable and if I'll need some kind of step up/step down mosfet arrangement at both ends. I know it's not a very expensive or complex thing to just build and try out, but it's always prudent to ask experts before switching on the soldering iron. So any advice or pointers on this would be appreciated :)

Many thanks
Mort
http://en.wikipedia.org/wiki/USB#Cabling
You have a limit.
5 Metre, or 3 Metre depending on supported data rates.
You may need to use a raspberry pi or other small computer closer to the dish to handle the USB WiFi device. Then you can simply setup a network bridge between the Wifi device and the Ethernet device on the small computer.
 
Last edited by a moderator:
http://en.wikipedia.org/wiki/USB#Cabling
You have a limit.
5 Meter, or 3 Meter depending on supported data rates.
You may need to use a raspberry pi or other small computer closer to the dish to handle the USB WiFi device. Then you can simply setup a network bridge between the Wifi device and the Ethernet device on the small computer.
This was what I was afraid of. Using a Pi or Arduino or something near the dish is certainly an option but I was trying to keep the amount of hardware on the dish side to a minimum mainly for the reasons of having to shield them from the elements. Thinking about it however, using a PI is a good idea, I have seen a POE mod for the Pi which would pretty much be ideal. I can then lob WRT on it and it should be a pretty decent device.
 
what is the need for a dish fed wifi system ?

Dave
Oh I dunno, the same reason that thousands of other people have made them maybe? Pretty obvious really, range. Google "cantenna" and it'll tell you all about it.
170px-5ghz_cantenna_as_satellite_dish_feed-horn.JPG
 
This was what I was afraid of. Using a Pi or Arduino or something near the dish is certainly an option but I was trying to keep the amount of hardware on the dish side to a minimum mainly for the reasons of having to shield them from the elements. Thinking about it however, using a PI is a good idea, I have seen a POE mod for the Pi which would pretty much be ideal. I can then lob WRT on it and it should be a pretty decent device.
You can put whatever OS you want on it.
You can configure the small computer as a Gateway, or use it to merely bridge the connection.

If you configure it is a gateway, you will most likely need to add a DHCP server to it, and it will hide/firewall any devices connected to it from anyone else on the wireless network you are using.
Otherwise, if you simply bridge the connection, every machine you have connected to it, and every other device on the wireless network will be part of the same subnet and will be able to communicate.
Pros and Cons, the options are up to you. (You could very easily stick it in a sealed container. The Pi does not generate much heat. If your concerned with moisture, you could submerge it in mineral oil, or find a potting solution that conducts a reasonable amount of heat.)
 

davenn

Moderator
Oh I dunno, the same reason that thousands of other people have made them maybe? Pretty obvious really, range. Google "cantenna" and it'll tell you all about it.

That didn't answer the Q

I know all about cantennas, wifi dongles in front of dishes etc
was wanting to know if you had a specific purpose in mind

A dish is going to produce a signal that is going to be reasonably narrow beamwidth
no good for coving a broad area like a house or other larger building ... its more point to point use
 
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