I would really like to build a wifi cantenna, but everyone seems to be posting instructions assuming you have a card that takes a pigtail. The computer that needs this is a stupid iMac, and as such has no abilities.
Can I take the signal from the wire poking into the can and get it correctly fed into a usb connector? Also, it seems there would be drivers needed for that. Could I try ones meant for usb wifi dongles sold commercially?
No, you can’t connect it to the USB directly. You’re missing the radio. It’s not a question of drivers - something needs to take the RF signal from your antenna and convert it back to data packets it can send over the USB. That’s what a WiFi radio does.
Are you asking if you could try a commercial WiFi antenna? No, same problem.
However, you could buy a commercial USB WiFi adapter with a antenna input, or a USB WiFi adapter with a built in high gain antenna like.
Ok, yeah, my networking knowledge is about 1 out of 10. So I would be stuck with buying something like a mini wifi usb adapter and putting it in a can. I’ve seen instructions for that. Would it then matter for the height of the adapter in the can and the distance from the back? When the instructions are for wire, they are very particular about that.
Increase the wifi reception for my buddy’s iMac. In the room it’s in, it seems to drop off the network and need the airport turned off and on. When it was moved to being right across the wall from the router, it performed fine.
I’m asking how much the height of the dongle/antenna/adapter/whatever and the distance from the back reflector matter. Apparently it matters quite a lot if you are building a cantenna with just wire as the internal antenna.
In a cantenna, the entire can is the antenna. You can’t just stick a USB wifi adapter inside of a can and expect it to work the same way. You would need to remove the USB device’s antenna and attach the cantenna to the USB adapter’s antenna terminals, which would require a bit of electronic surgery to the USB device. Based solely on your posts here, I believe this is a bit above your technical ability level.
If I understand you point, then I you seem to be arguing with instructables on that previous site, where people are saying that they literally took the entire wifi adapter and put it in a can, running a usb extender cable to the computer.
I guess the easy way to use that would be to put the antenna into the can in the correct position, glue it down, and run a usb extension cable to the computer. But since the antenna needs to be a right angle to the body, it would be hard to vary the height of the antenna in the can.
OR: Is the antenna already sized for the wave size, and the whole antenna should be poking into the can? That would take the sizing issues out of the way.
Another solution could be to move the router. The iMac doesn’t have an external aerial for its WiFi so you could move the wireless access point closer to it.
Does the router have one or two aerials on it? If you have two, you might get the improvement you need by putting the improved aerial at that end, using one aerial port.
As for your question about height and distance inside the can, the design of the cantenna is constrained by the e-m signal characteristics. That is, because you are using WiFi which has a defined frequency band, your dimensions relate to the wavelength of the radio signal. So the position of the probe in the can is critical to getting improved performance. I note that one of your links has a link to an aerial shootout. Their results showed equal performance with a Lucent 2-3 dBi gain omnidirectional. If the can was working properly I would expect much better results from it than the omni aerial.
About all we can say about the aerials is that they seem to be getting some signal into the WiFi port. That’s not a great recommendation for the homemade aerials.
The USB dongle design is making an assumption that putting the dongle’s RF part in the right place will make the aerial work. I don’t think that is so. The aerial feed (the coax connector and probe) is designed as a transition i.e. transferring the signal from cable to free space. It’s the most important part of the design and is tricky to get right. If you read the online antenna book, section 6.3, from one of your links, you’ll see that mentioned as one of the hardest bits to get right. They are talking about using a coffee can as the feed for a parabolic dish, but the feed on its own is the same as your cantenna.
Oops! I see that your later replies mean my first suggestion won’t work. The latter bits are still relevant though. i suspect that a lot of the improvements people get from things like the dongle in the can is because they get the aerial up higher and clear of the desk or table the laptop is on. Also, the cable means you could get it closer to the source router.
OK.
The reason I ask is: there are many routers that support high-gain antennas. If it was his, he could just buy some and install them. I think a better solution than the Cantenna might be getting an older LinkSys WRT54 router and installing the open-source software DD-WRT on it. This will allow you to put the router into “bridge” mode, and then you can position the router wherever you like, and run an ethernet cable to the iMac. I think this is better than trying to make a Cantenna for the first time.
Free space simply means the signal becomes a radio wave and radiates from the aerial. The cantenna is the whole aerial. Changing the probe to a dongle transmitter/receiver is like changing one wheel on your car to a sledge runner. It doesn’t match the design of the rest of the vehicle.
If you put your dongle the right distance from a reflector of the right size, you would get a theoretical increase in signal strength in some directions, nominally the opposite direction to the reflector. Because radio signals are reciprocal, both send and receive would increase in strength. The can may act as a reflector for the dongle, but is probably not optimum for that purpose.
I understand if you are piggy backing off the next door neighbors signal (you indicate with permission) if would be a pretty big imposition to ask her if you can begin goofing around with her router to make your signal better.
I had a similar problem when i moved my notebook to the opposite end of my house far way from my router which I solved by using this old school adapter. The 6 foot cable let me place the antenna height 7 feet up on the wall which substantially improved reception. Took me from marginal to OK/Good reception
For most residential service ISPs, this is a direct violation of their terms of service, and she can have her account terminated if they find out about it.