By using PVC, all-thread, washers, some cheap copper tubing, a Pringles can, and some scrap cardboard, we were able to make a prototype shotgun yagi in a matter of hours. In about 45 minutes, we had the collector rod built, the locknuts on, and the whole thing in place. The result is a Pringles can that pulls about 12db!
Yagis and dishes are much more directional than sectors and omnis. This bore out in the numbers, as the perceived noise level was consistently lower with the more directional antennas. This can help alot on long distance shots, as not only will your perceived signal be greater, the competing noise will seem to be less. More directional antennas also help keep noise down for your neighbors trying to share the spectrum as well. Be a good neighbor and use the most directional antennas that will work for your application (yes, noise is everybody’s problem.)
When trying to aim a yagi (like our little can), keep in mind that they have large side lobes that extend up to 45 degrees from the center of the can. Don’t point directly at where you’re trying to go, aim slightly to the left or the right. We also found that elevating the antenna helped a bit as well. When aiming the antenna, hold it behind the connector, and SLOWLY sweep from left to right, with the Link Test program running. When you get the maximum signal, slowly raise the end of the can to see if it makes a difference. Go slowly, changing only one variable at a time.
Remember that the can is polarized, so match the phase of the antenna you’re talking to (for example, if shooting at an omni, be sure the element is on the bottom or the top of the can, or you won’t be able to see it!) You can use this to your advantage to try to eliminate some noise on a long distance link: slowly turn both ends of the link from vertical through horizontal, and stop at the point that you see the most gain (and lowest noise.)
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