Sup /g/,
I'm in the market for a high gain Wi-Fi antenna, and I was thinking about this one here:
http://www.newegg.com/Product/Product.aspx?Item=N82E16833997212&nm_mc=KNC-GoogleAdwords-PC&cm_mmc=KNC-GoogleAdwords-PC-_-pla-_-Network+-+Network+Antennas-_-N82E16833997212&gclid=CPvY2vnAnssCFYE9gQodwg0Leg&gclsrc=aw.ds
Can these things really pick up a signal from 35 miles away? What kind of reception can I expect with one of these and how can I get the most out of it?
>Can these things really pick up a signal from 35 miles away?
Reliable link at that distance depends on many things OP. Transmitter power, receiver sensitivity, cable loss, path loss (antenna height above surface, obstacles, etc), modulation, data rate, error correction, frequency, interference.
>>53255191
I figured 35 miles is pushing it if you're looking for a reliable connection. I live in an apartment complex a few miles from the downtown "night life" area of my city. It's full of shops, restaurants, clubs, and things like that, which offer free Wi-Fi to customers. Would it be able to hold a reliable connection if the signal from one of those places is about two or three miles from my apartment?
>>53255191
>Reliable link at that distance depends on many things OP.
Yeah, whether it's TCP/IP or UDP
>>53255153
Brotha I have this service.
It has the capability of good bandwidth and latency; but it's very, very expensive.
I'd use this as a last resort if cable is not available. Because satellite internet is terrible.
>>53255325
i'm not that guy but with a good antenna and no tall buildings between you yeah you should but expect shit latency
you should actually build your own biquad antenna with an old satellite dish instead of buying one, much cheaper
Not gonna say it is impossible, but at that distance, at least one side will have to be on a tower on top of a mountain (very tall hill). The other side will need to be on a tower. You will also need top of the line transceivers with full output power. The high-gain antennas will definitely be required. You probably won't get it (WI-Fi) to work, but never know until you try. Something like narrow-band VHF wouldn't be a problem at all with those distances, but doesn't sound like that is what you are looking for.
Sweet, an antenna thread. I'm in the market for a 2.4Ghz directional antenna too. I'm thinking yagi since they're reasonably size and priced. I'll just have to figure out how to mount it to a tripod
>>53255153
Be careful.
There are regulations on transmit signal strength. It is a common error not to factor in the gain of the antenna.
There was a case some years ago when a university was setting up a link across a wide stretch of water. They used a legal transmitter and a huge paraboloid reflector. They were told to de-rate the transmitter because, with the parabola's gain, they were over the legal limit.
>>53255153
Easily if you have a clear view of sight and you align both antennas perfectly.
>>53255325
Don't forget that this isn't simplex, like TV. It's full duplex, because you need to send requests etc.
Your local router has to be able to be heard by their router or it's no go.
http://www.instructables.com/id/Easy-to-Build-WIFI-24GHz-Yagi-Antenna/
Yeah... round trip delay might make this a no go.
>>53255401
>>53255405
>>53255421
>>53255464
>>53255615
So I'm curious, what's the point of a high gain antenna if they're so incredibly finicky about holding a connection?
>>53255738
They make a 5 mile link a no-brainer. 35 Miles for a high-speed link is no as easy with current protocols and the current limitations of the speed of light and all. Not to mention that high-dynamic range modulation schemes like OFDM require insane amplifier linearity and so average (RMS) output power is usually shit.
>>53255153
If you had two of them aimed at eachother then they could. You're not going to get a 35 mile signal with one of these and a router. You'd get the most out of it by making sure it's precisely pointed at the transmitter you want to link to.
If you ever want some good reading, look up the AT&T long lines system. it was the backbone of TV and phone communications before satellites and fiber were around.
>forgetting curvature of the earth over 35 miles for line-of-sight signals
>forgetting telescope to align high-gain parabolics
>forgetting speed of light with regard to acks
>forgetting the brave new world of FFT as a modulation scheme
quick bump before this dies
I'm getting me an external wifi card so that I can fuck around long-range, I'll need a good antenna
>>53258249
That's what bolts and the ground are for.
>>53258249
That dish is delightfully DIY. I set my mom's house up with a repeater and a salvaged satellite dish pointed at the neighbor's poorly-secured WiFi
ITT: retards that don't understand the limitations of 2.4ghz.
The distances you guys are talking about aren't realistic. Even if you were to bump the frequency down to 900mhz, you could only get 2 miles, tops. There's no way you're getting more than half a mile on 2.4ghz.
>>53255153
Straight up OP, won't work for you if your plan is to leech off of others like you mention >>53255325
You need TWO units for every connection, so yeah, no luck. No way you're installing one of those on someone else's property and stealing their wifi.
>>53258555
>multiple extremely high gain antennas, one vertically polarized, one horizontally, and one cylindrically polarized or whatever its called
>every one has a large reflector dish
>20 watt transmitters
I have a teeny tiny 5 watt transmitter, and that thing can shut down my entire house's internal wifi if i set it to connect to an ap with an overlapping channel.
https://youtu.be/LG-AZz_nm5E
>>53255554
If I were to build one of these, how far away could I connect to a WiFi point?
>>53258555
I had a set up with two antenna like the one in OP picture and it was around 3Km without problems.
>>53258659
If only 1 devices has it, it'll only extend the range maybe a few dozen feet.
At the end of the guide the guy says
>I was able to see the WiFi of a hotel that was 2 miles away from my home.
but see doesn't necessarily mean connect. Both devices have to be able to transmit that far. The other device probably won't pick up what you're sending.
>>53258555
https://en.wikipedia.org/wiki/Long-range_Wi-Fi
>>53258555
I've easily made 65 mile links from hilltop to hilltop at 900MHz with 1 Watt transmitters. Now who is the retard?
>>53258607
>>53258659
gain is just a measure of how directional broadcasting power and listening sensitivity are.
10 dB = 10x more power between ideally aligned transmitter and receiver, which is the equivalent of being about 3.16x closer thanks to signal strength weakening with the inverse of the distance squared.
So if you went from a ~4 dB omnidirectional antenna to a ~24 dB parabolic monster, you could connect from roughly ten times further away, things like line of sight notwithstanding.
Long range links are generally meant to have directional antennas on both ends to actually be functional, so don't expect to be able to steal WiFi from somebody living a mile away using an unmodified AP.
