Boosting your WiFi signal

[OFSO]

I saw a clip on YouToob where two geezers built a cardboard and alumimum foil parabolic segment reflector which clipped over the antenna on the WiFi router and boosted the signal in one direction by some amazing amount - they claimed.

I have my router affixed to the interior wall at one side of the house with the antenna about 5cms parallel to the wall and all users are on one side of that antenna.

So I bought a sheet of aluminum, bent it into a very precise arc (no not really, I just guessed) and glued it to the wall behind the router antenna.

The before and after results in our bedroom*, the furthest room away from the router, are that I now have one additional bar showing on my smartphone screen. For about €3, an easy modification to try if your WiFi rig is at one side of the house.

This is what it looks like: the erect black object is the router antenna, the box what it emerges from is the router itself, and the curved bit is the aluminum sheet. Signals are reflected towards the viewer (as it were).

Is that explicit enough ? If not, photographs may follow (*not of our bedroom, though, it's too exciting).

[Ancient Observer]

Thanks.
Sounds like a great idea.
I bet Loose tries it and it takes about 3 years for it to work.

[Loose rivets]

The very day I was going to set up the two routers to relay the signal to me - I'd got a good signal at the relay point - said mate bangs on me door. His brother was willing to lend me his USB-powered boosted aerial. In combination with inSSIDer, I can position it for very fair results. As said ont'other thread, putting the thing on the floor didn't get more oomph, just a reduction of other people's signals. Since my old signal was so variable, I'd guessed it was other folk switching in and out on my channel.

A good reflector should have a distance from the aerial that's a sub-multiple of the wavelength. Ideally, the length would be critical, though I'm not sure how that works with a curve.

Erm, in the Gig range, I guess a sub-multiple might be a bit difficult.

[le Pingouin]

You're thinking of a single element "reflector". This is literally a parabolic reflector as per a satellite dish or radio telescope. Radio waves bounce off the surface & are focussed on the antenna. Get the shape right & position it correctly so the focus & antenna coincide or things won't work too well.

[Keef]

Reflectors should work if you get the size and shape right and put the aerial at the focus. You can also buy Yagi aerials for WiFi frequencies: they work well.

I've found that moving the standard aerial a few inches in one direction can improve the signal several bars, too.

[FullOppositeRudder]

Thanks OFSO - it's a simple addition to your system which has obviously helped. The basic design is widely used throughout many areas of radio signal work.

There is a fairly useful treatise on this subject - including pictures and some very imaginative design and construction considerations here.

Regards,
F-O-R

[OFSO]

Well, what I made wasn't trial-and-error, it was (a) measure signal strenth on smartphone in distant room (b) bend aluminum to what looks right and stuck it on wall behind antenna (c) go back to distant room and measure signal again, one bar more, hmm, not bad, can't be bothered fiddling about with it !

And on that subject: once upon a time it was discovered far too late, that a technician employed in a satellite cleanroom had accidently struck one of the axial thrusters on a shiny new spacecraft, knocking it skew-wise with a hammer while working on the transport baseplate. After launch, attitude manoeuvres went just fine. At the Board of Inquiry he explained he hadn't bothered to report the accident as, (and I quote) "I just tapped it back into place until it looked right again".

That's the way to do it !

[OFSO]

FOR, having looked at that link, my device is VERY similar. I mounted the router high up near the ceiling to avoid WiFi radiation coming through my head as I sit at the PC (yes yes, tinfoil hat and all that stuff) and it's in the rear corner of the house. Because of this and because it's glued on the wall I made it slightly asymetrical to include rooms "to one side".

Here's the photo: the aluminum sheet is so reflective what you see here is a reflection of the ceiling tile. The router is screwed to a bracket fixed to the wall, and the cables drop down in a duct to where the WiMax power supply and connector is located. The WiMax cable goes through a hole in the wall and up to the small quad antenna on the roof, pointing at a mast about 15kms away. Stains on the wall ? Where I had a massive cooling duct glued with silicone !


I have been all round the house and get improved signal strength, one thing I did not do (and wish I had) is check the before and after signal strength 'behind' the reflector.

Incidently I can receive a good signal from the harbour yacht marina WiFi about 5 kms away on my smartphone, next thing will be to build a yagi looking that way.

OFSO

[green granite]

How-To: Build a WiFi biquad dish antenna -- Engadget

[tony draper]

Bah! nowt wrong wi a length of good honest copper wire.

[OFSO]

Spent a pleasant afternoon on the terrace with an old laptop, a WiFi USB dongle on a lead, a sheet of aluminum, a collander, a strainer and a few other hemispherical objects. Signal gain improvement with even the most haphazard assembly was over 10% but signal quality improvement was far greater. Then Mrs OFSO came up and wanted to know what I was doing with her kitchen implements so I had to pack it in.

A great way to spend yet another cool grey Spanish summer day.

[FullOppositeRudder]

Then Mrs OFSO came up and wanted to know what I was doing with her kitchen implements so I had to pack it in.

Alas I know how that feels. One is on the brink of a new scientific breakthrough and the equipment is repossessed for mundane purposes.

Thanks for sharing this with us - very useful (if simple) ideas for future challenges. Improving the WiFi signal can greatly enhance the end result.

Regards,
FOR

[mixture]

Concentrating your WiFi signals into a more focused beam sounds like a lovely way to get yourself a brain tumour.

[The Flying Pram]

I made this to improve the signal from our bird nesting box camera, and also to reduce the interference being picked up from the microwave oven! The aerial came with the receiver box, and I've extended it with good quality 50ohm co-ax and SMA connectors. The gold plated plug body is in contact with the metalwork to help with the shielding.

[rotornut]

I'm always a bit nervous about sending out too strong a signal. Even though I have state of the art security there`s always a possibility that some evil-minded hacker could get into my system. So I turn it off when I`m not using it and keep the modem in a place where the signal is just adequate for the laptop in the next room.

[OFSO]

1) Safety: the WiFi router antenna is mounted about a metre and a half above my head, and almost directly above my head, antenna is vertical and radiating straight out, not down. So I think I'm in a side lobe if anything. The far more powerful WiMax antenna is maybe 5 metres above our heads out on the rooftop and is directional out over the rooftop to the east.

2) Security: the maximum available on this router. WPA-PSK etc. The name of the installation is also one digit away that from used by some ten or twelve municipal hotspots in the nearest town, 5kms away and 600' down the mountain. So not immediately identifiable to me or my house. A hotspot has just appeared next door with a very similar name but completely unguarded. Hopefully rather than trying to crash mine, people will use that.

Has anyone found some simple software which will show what a WiFi router is being accessed by at any time ? I too would like to know.

[FullOppositeRudder]

Has anyone found some simple software which will show what a WiFi router is being accessed by at any time ? I too would like to know.

Both of my router devices have a page in their configuration menus which lists the "connected devices" identified with the MAC address for each connected device. It means rummaging around the menu systems which may have varying degrees of ease of interpretation. Hunting down the DHCP table should show this information

There may be external third party software which does the same thing, but I've found the router (sub)menu option satisfactory for my own purposes.

FOR

[FullOppositeRudder]

I'm always a bit nervous about sending out too strong a signal. Even though I have state of the art security there`s always a possibility that some evil-minded hacker could get into my system. So I turn it off when I`m not using it and keep the modem in a place where the signal is just adequate for the laptop in the next room.

It's a good point. Using the most secure log in system goes a long way to ensuring that your system is intruder proof. Using a MAC address permissions table where possible and convenient is also an excellent further step.

Regarding levels of RF power and its effect on people in the vicinity, that's a subject which could involve a lot of ongoing discussion. These days we live in a world of almost constant RF exposure. I would still be more concerned about the long term effects of my constant companion mobile phone than that which involves the use of my WiFi system, even if I had the need to concentrate the signal on any given area where humans abound (which I don't). It's a big subject on which the (informed) jury is still deliberating!

I suspect that mostly, it's considered to be OK at the exposure levels encountered in the average home or office. However every so often information comes to hand which gives rise to some angst.

respectfully,
FOR

[Mr Optimistic]

I am not sure that 'bending' the metal is entirely necessary as in terms of focussing. A plane sheet of metal will act as a reflector giving a signal distribution that is the same as if you had two antenna, the real one plus its 'image' in the metal (as if metal was a mirror). If you put the metal too close to the antenna (near field) you will screw up the impedances and this would be a bad thing. Think you would want it a significant fraction of a wavelength away, which at 2.4 Ghz with c= 3x10^8 is.....a bit bigger than 0.1m so say a fifth of that, 20cm. Now the issue is how much of the radiated energy going 'backward' towards the metal is actually intercepted,so want a big sheet.

There is a 180 degree phase shift from the image (to null out the field at the metal), so side on will give no signal. So if you are trying for constructive interference don't forget to add a lamda over 2 to allow for this.

EDIt: In terms of health, can't say I would be too worried at the signal strengths involved. The most sensitive part of your anatomy (above trouser level) are your eyes. High radiation causes the humours in the eyes to denature and they go opaque as per cooked egg whites. So desist at the first signs of blindness would be my advice. Other thing is that I suspect half the wifi issues I experience are more to do with multipath interference than raw signal strength, though such interference will get worse at low signal levels. So, check out any big metal things (eg range cooker ) in LOS between router and computer.

[OFSO]

page in their configuration menus which lists the "connected devices"

Thanks FOR, it's listed as DCHP Client List in my software which translates as connected devices. Not obvious but why name things the simple way ?!