C/P from some old how to's I have already on my PC :
Build A Tin Can Waveguide WiFi Antenna In One Hour. Extreemly Powerful range extender signal booster
Extend range boost signal with NO Coax db Loss and Plenty of GAIN. Then put it on a 18" inch direct tv dish, (optional).
(This is very simple and most can build this very easily)
Build A Tin Can Waveguide WiFi Antenna Without Coax Loss In One Hour. Then put it on a 18" inch direct tv dish for even more distance.
Homebrew 2.4 Ghz WiFi waveguide antenna for 802.11(b or g) Wireless LAN Networks or other 2.4GHz Applications.
This design works so well because it is so simple. There is no coax loss because there is no coax ! The only thing that exits this WLAN antenna is a USB cable. I do not have to give up any db gain to my feedline. 2.4ghz is very lossy in coax.
This is an un-scientific discussion based on my observations and experience with building 1.2ghz waveguides for my past AMATEUR TELEVISION stations.
The WLAN device I chose for this project antenna was the D-Link DWL-G120 54Mbps Wireless-G USB Adapter. I chose it because it has a FLIP UP ANTENNA that I could slide directly into a waveguide can. NO COAX!
So far I can connect and stay connected to WAP wifi HOTSPOTS 3/4 mile away at 24mbs daytime and 54mbs at night when my host's bandwidth increases due to less traffic. Now those are the only locations I have identified. I get several open wifi networks from here, but do not know where they are. My antenna may work past 3/4 mile.
My Wireless-G USB Adapter out of the box claims a range of Indoors: Up to 328 feet (100 meters) and Outdoors: Up to 1,312 feet (400 meters)
This antenna has a gain of at least 3dbd, (x 2 power). So 1,312 ft. x 2 = 2,624 ft. Long distance hotspot LAN access. I think I am doing 4,000 feet so far. Another factor that is equally important is the NOISE LEVEL.
All the unwanted network signals swamping the receiver's front end cause LINK DROPOUTS. This waveguide reduces the noise level allowing me to hold the more distant hotspots I aim at and null the others.
A LEAP FORWARD TO EVEN HIGHER POWER. The next step. Amplify signal to waveguide with a satellite dish. Reason? I lost my origional wifi hotspot. The waveguide alone would not link to a more distant MUCH WEAKER WAP. I needed to extend my range and boost my signal.
This antenna is in use and aimed out and through my radio room window. It is currently aimed at a distant high speed system router BEYOND THE BARELY VISIBLE TREE LINE in the top horizon below the mountains past all visible buildings as you can see in 2nd photo. It is a free public wifi system, but I am over a mile out of cantanna usable range. This dish did the trick.
Here is the same waveguide cut down to 3 1/4 inches to capture the focal point of an 18 inch Directv dish. NOW, IT IS NO LONGER A WAVE GUIDE. IT HAS BECOME A BACKFIRE FEED. I HAD NO ROOM TO USE THE MORE EFFICIANT ORIGIONAL GUIDE LENGTH WITHOUT BUILDING A NEW MOUNT SET BACK TO COLLECT ALL ANGLES OF THE DISH'S REFLECTION. The focal point maximum illumination must be at the entrance of feed can, not the antenna inside. Before I cut the old wave guide post off the origional factory tv lnb feed, I measured the focal point to the metal entrance under the plastic cup. I had to maintain that distance. The focal point remains constant inspite of frequency change. It really works well, grabbing links that the can alone was unable. Some day if I need even more gain, I will rebuild the mount and utilize the full length wave guide. This works so well, I do not see any need for a re-work.
I chose a USB device that could attach to the feed horn to bypass the need for a lossy coax cable to a wifi device away from antenna. Even a couple of feet of coax at this frequency, (2.4 ghz) will severely diminish the signal, makeing the dish a useless waste of time. There is no meaningful loss in a usb cable to computer under 16' runs or 80' with repeater cables end to end. I am running 32 feet of USB REPEARER CABLE now. I AM DELIGHTED WITH MY NEW HIGH SPEED CONNECTION. VERY STRONG RELIABLE SIGNAL. Solid Full-smash connection.
This works Great, can be set up really easy on or outside your camper