Wifi through satellite dish

mikeisyou

mikeisyou

More than regular member
Messages
437
My Satellite Setup
Fransat 4K with Basque ETB channels, Octagon SX88+ and Motorized 1.25m Raven Dish (37w to 46e)
My Location
South coast of England
Hi All,

I've been thinking about getting a wifi dongle https://www.amazon.co.uk/802-11ac-Wireless-Network-Adapter-10-4-10-12-5-8ghz-600mbps/dp/B077HV82GH/ref=sr_1_2?s=electronics&ie=UTF8&qid=1518733713&sr=1-2&keywords=5.0+ghz+band so I can use to pick up free wifi from a mile away. Luckier enough I live on a hill and the location with free wifi is also on a hill so I do have a line of sight with the building so it shouldn't be too hard. I have seen lots of tutorials on youtube with people using the dongle as a lnb pointed at their satellite dish. Has anyone on the forum tried this before? I have a spare sky minidish but it might not be big enough for the job.

The usb dongle has a coaxial connection so it can be connected to a regular lnb but I'm not sure what lnb would be best for receiving 2.4 and 5.0ghz signals.
 
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Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
Staff member
Messages
27,498
My Satellite Setup
A little less analogue, and a lot more crap.
My Location
UK South
Sky dish is suitable though you would need to check the gain figure of the dish at the WiFi frequency.
There is also a ‘spread ‘ factor of using a stick at the focal point, instead of a dedicated feed system, so this will detract from the overall performance in the direction of the signal.
 
mikeisyou

mikeisyou

More than regular member
Messages
437
My Satellite Setup
Fransat 4K with Basque ETB channels, Octagon SX88+ and Motorized 1.25m Raven Dish (37w to 46e)
My Location
South coast of England
Sky dish is suitable though you would need to check the gain figure of the dish at the WiFi frequency.
There is also a ‘spread ‘ factor of using a stick at the focal point, instead of a dedicated feed system, so this will detract from the overall performance in the direction of the signal.
Thanks, I was thinking about unscrewing the stick antenna and just connecting directly to the lnb of the dish even though Ku-Band operates between 10.7 GHz ~ 12.75 GHz. Despite this in the past I have been able to pick up DVB-T Freeview by plugging the coax cable into my tv. C-Band operates between 3.4 ~ 4.2 GHz so maybe a C-Band lnb might work better.

I have a spare aerial aswell so I could give that a go.
 
Terryl

Terryl

Specialist Contributor
Messages
2,341
My Satellite Setup
OpenBox X5 on a 1 meter motorized dish.
And now a 10 foot "C" band dish.

Custom built PC
My Location
Deep in the Boonies in the central Sierra Nevada mountains of California.
Don't try plugging it (router???) into the LNB feed from the dish, you need at least 14 volts DC to run the LNB and it's at the wrong frequency.

I've done WIFI on a "C" band dish, worked great, I mounted everything in the cone that covers the LNB on the BUD, I used the standard WIFI antenna you get on the router on a USB WIFI adapter, for the extra distance to keep the signal loss down for the small coax used, I used a USB to CAT 5/6 adapter with POE injectors.

I got about 2 miles with it at ground level (about 6 feet off the ground) and in one setup it was hill top to hill top at about 10 miles.

A standard "Ku" band dish is too small and shaped the wrong way for 2.5 or 5 GHz signals, but it could work if your close enough to the WIFI source.

I have photos but I'm not on that PC right now.
 
aceb

aceb

Specialist Contributor
Messages
1,479
My Satellite Setup
Prof Tuner 7301 /
1.25m Gibertini + Inverto B.Ultra/C1W, Moteck H180, 68.5E-67W Ku/C-Band /
1.8m Precision PF + ESX241/Inverto Black Pro, 66E-63W Ku/C-band /
2.4m Fortec Star+Titanium C1W/Pride plate, 49E-58W
My Location
Sussex
No regular LNB is going to work at WiFi frequencies and no LNB is going to work with a WiFi dongle as part of a link system. You might have some success fixing a dipole onto the stick and putting that at focal point but the gain will be very low on a Ku dish and using a C Band dish as a point to point link really isn't practical. It would be a lot easier to use a Yagi or reflector designed and built for WiFi.
 
Terryl

Terryl

Specialist Contributor
Messages
2,341
My Satellite Setup
OpenBox X5 on a 1 meter motorized dish.
And now a 10 foot "C" band dish.

Custom built PC
My Location
Deep in the Boonies in the central Sierra Nevada mountains of California.
Terryl

Terryl

Specialist Contributor
Messages
2,341
My Satellite Setup
OpenBox X5 on a 1 meter motorized dish.
And now a 10 foot "C" band dish.

Custom built PC
My Location
Deep in the Boonies in the central Sierra Nevada mountains of California.
But you have to remember that WIFI is a two way street, your signal must be able to get to the WIFI access point, most routers only have up to 600 mW of output power, the coax loss at 2.5 GHz will drop that down to where your out in the mud, the access point may never see you, you have to bump your output up, they make 2.5 GHz amps that are bi-directional, this way you can compensate for the coax loss.

This is also why I mount everything in a water tight box right at the antenna.
 
Fisty McB

Fisty McB

Member
Messages
258
My Satellite Setup
Currently under redevelopment.
My Location
County Tyrone, N. Ireland
Bit late replying to this, but using a S*y Digital satellite dish for WiFi use is most certainly possible. Saying that it's been two or three years since I last experimented with it, which I'll talk about shortly.

Earlier this decade I moved into a flat which was reasonably high up on the edge of town with a good visual view of it. Experimenting with a USB WiFi adaptor showed that a weak but usable "free wifi" (that's free as in free beer) signal was detected at a window, so I bought for a couple of quid at a pound shop a mesh cake cover. Whilst not parabolic, adjusting the aerial on the WiFi dongle to poke through the middle-top of the cake cover gave a useful increase but was subject to periods of suddenly stopping for a couple of minutes before starting again. Not long afterwards I took an old 2 litre plastic bottle, covered one half of the round side of it with aluminium foil and placed a spare collinear 2.4GHz aerial roughly at its focus point to give something like a 2D parabolic crossed with a corner aerial. This worked very well picking up this free WiFi hotspot with far fewer dropouts than using the mesh cake cover and it kept me going for at least three months before I got ADSL installed (it was with S*y, please don't judge me, I was young, had little money and a new landline had to be installed that I only paid £10 for. I quit after the 12 months and I reckon I cost Sky more that what they took from me. So I've a clear conscience I reckon). In case you're wondering where the Free WiFi was coming from it was from a local McShite that was 320 metres (almost) line of sight to my flat window. Can't remember who was the provider at the time but they had outdoor coverage at ground level over a decent distance. Several months later they changed the free customer WiFi to O2 which had less outside overspill, and reception at my flat window with the 2L bottle aerial was down in signal strength to matching that of the unaided dongle of the previous provider.

Fast forward on a couple of years into my present abode and again it's quite high up compared to the surrounding area. One evening I decided to experiment with a S*y Zone 2 dish balanced on a chair looking out the window, with the LNB removed and the said dongle used for the initial flat tests positioned so its external aerial was roughly at the focus point (little adjustments made to try and get it right without fully succeeding). It was very much a ramshackle set up - the dish couldn't fully look "down" through the window and I didn't experiment with the dish upside down to compensate, and the simple monopole external aerial of the dongle certainly didn't "couple" well with the dish with its omnidirectional radiation pattern, but it did reasonably well. While the bare dongle aerial picked up between 7 and 9 APs depending which way the wind was blowing, the Zone 2 dish and dongle combo picked up 92 APs over a 15 minute period. One AP that was particularly noticed was that of my parent's BT Home Hub 3 router! That covered a line of sight distance of around 850 metres though it was weak (highest received signal level was -88dbm) and would have certainly have benefited by the dongle aerial having even a small amount of directivity towards the dish surface.

There's plenty of demos and write ups of using discarded and unused satellite dishes for WiFi point-to-point use though most examples seem to come from the USA or Canada. In fact I have not come across one that involves the use of a S*y dish, either Zone 1 or Zone 2. I suspect performance might be similar to the DirecTV and Dish satellite dishes that are a wide oval shape to take in multiple LNB focus'. One problem using these dishes or any offset dish is that with the 40mm standard Ku Band LNB neck size this is much to small to accommodate a waveguide that will operate on 2.4GHz, so a little imagination might be needed as to how to get the pick-up aerial to properly stay at the focus point. Quite popular is the use of "biquad antennas" at the focus point, some also use waveguides like "cantennas". Certainly a unidirectional aerial aimed at the dish surface will help matters more than a small omnidirectional one, though don't use something whose beam is so tight it can't see most of the dish!

As for dish sizes, I recall reading once (probably years ago in a copy of WotSat) that for a parabolic aerial to contribute gain it must be at least one wavelength in diameter of the lowest frequency that is intended to be received. If the parabolic surface is solid then it doesn't really matter what frequency it is being used on to help receive (mesh/perforated ones have some limitations) but the higher the frequency for the same given surface area, the higher the gain - but also the tighter the forward beam will be. From some very rough calculations a 45cm solid dish or Zone 1 dish can still give a decent gain over a simple monopole, though the gain achieved would be on a par with a good high-gain yagi-uda designed for frequency range. Once you started hitting dish sizes from around 70-75cm and bigger you then can get gain figures that'll outperform pretty much all yagi-uda's, in the region of a gain between 18-23dbi. For 5GHz WiFi, this gain will increase further albeit with a narrower forward beam.

One concern would be as to how you'd intend to feed the signal from the aerial at the focus point down to the transceiver. You could get away with say a USB dongle mounted on the dish which was then fed to a computer by using USB cables provided everything involved that's outdoors (except the dish itself) was suitably weatherproofed or rated for outdoor use. Power over Ethernet is another option if it allows. Coax cable is tricky given the losses at 2.4GHz and especially 5GHz. On the face of it the common WF100 coax cable might be OK for short-ish runs, the main problem being impedance matching but the loss of signal between an impedance of 50 ohms and 75 ohms mismatch is fairly marginal that in most cases for receiving it hardly matters - for transceiving with the 100mW EIRP power limit in the UK and most (all?) of Europe I'd say you're unlikely to damage the likes of dongles and access points through a high SWR (In theory a 50-75ohm mismatch will give a SWR reading of 1.5:1 which gives a fraction of a db loss). I must admit using 75Ohm cable for feeding WiFi isn't something I've done before so I might experiment doing it later this year. As mentioned, coax losses at 2.4GHz can be significant even though WF100 standard coax is now intended to carry frequencies up to 2.340GHz for Sky Q so probably best to limit it to a maximum of 10-12 metres before cable losses start being significant.

Maybe more later.
 
Terryl

Terryl

Specialist Contributor
Messages
2,341
My Satellite Setup
OpenBox X5 on a 1 meter motorized dish.
And now a 10 foot "C" band dish.

Custom built PC
My Location
Deep in the Boonies in the central Sierra Nevada mountains of California.
Don't forget the adapter, the normal connector for 75 ohm coax is an "F" style, trying to find an adapter to go from that directly to the reverse SMA on most routers is a bit difficult but I have found one source.

RP-SMA-Male to Type F-Female Coaxial Adapter Connector

In most cases the adapter loss for this application is very small around .15 dB, (times 2) but with the standing wave ratio at 1.5:1 due to the coax impedance miss match you only have a return loss of 12 dB, (this needs to be as high as possible) this may affect the small amp used on most routers as it is looking for a very small SWR (1.1:1 at best) with the antenna directly attached to the back of the system, also at a SWR of 1.5:1 you only getting about 95% of the signal out to the antenna, your loosing 5% right off the bat.(at the TX output)

I have found with many years of testing and using many different setups I have found that the signal loss is too high to do any good with a standard routers output at only 100 to 200 mW, (sorry I was wrong in my post above, I was quoting the output of my router) with all the connections and with what ever loss in what ever coax length your using the actual RF signal at the antenna input will be very low. (around a few milli watts if that)

And most of the antennas supplied with the routers have little if no gain if they are used at the far end.

This is why I have gone to the USB type WIFI adapters, these can be mounted right at the antenna (with proper waterproofing) or as close as possible to the antenna, then USB to CAT 5/6 adapters can be used to go around the coax losses, and POE devices can deliver the necessary DC power to run them.

On most setups around here it looks something like this, at the PC or laptop a USB to CAT 5/6 adapter is used along with a POE device (if needed) the the CAT 5/6 cable is run out to the antenna location, (this can be several hundred feet) at the antenna site a water tight enclosure is used to house the USB WIFI adapter (one with a removable antenna) along with the CAT 5/6 to USB device and the POE adapter.

In this way your signal has the best chance to get where you need it to go, in really long range applications I use an Alpha AWUS036NH 2 watt WIFI adapter, now with this hummer you can really reach out there, even better when mounted directly at the antenna.

One like this....https://www.amazon.com/Alfa-AWUS036NH-802-11g-Wireless-Long-Range/dp/B003YIFHJY

The only draw back to using that one is that you need to use an externally DC powered USB hub to run it as it is very power hungery, but all this can be enclosed in the WT box at the antenna.

In my experience using a satellite Ku band dish for WIFI has not proven very effective, the only type of satellite dish I have seen that had done anything for bidirectional WIFI signals has been a "C" band dish, but these are very large and not too good for ground level work. (most are mounted at or near ground level)

Home made cantennas are effective to maybe a few blocks or less in a city environment, but when a proper WIFI rated yagi antenna along with the USB equipment I have described and used at many locations, plus mounted at a sufficient height to clear most ground level obstructions, has been effective out to 1.5 to 2 miles, for bidirectional WIFI.

And if you use a standard TV antenna rotor you can search around for many different WIFI access points.
 
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