Waveguide "Cantenna" vs. Parabolic dish: Which Is Better?

Hi. I want to make an enhancer for my wireless usb adapter. I've noticed that the two main types are "cantennas" (Google it), which are waveguide antennas, and parabolic style ones. (Google "wok fi"). These are simply a parabolic-shaped object, like a wok or a kitchen strainer, with the usb adaper placed near the focal point.


I've noticed that as a general rule, parabolic style ones seem to have the dongle/adapter placed in front of the bowl, whereas the cantennas usually have a 1.21" copper wire from a cable going into the can.

Placing the whole adapter in the can obviously looses some of that precision, but does that make a large difference? Would it greatly reduce the cantenna's effectiveness?

I don't plant on taking apart the adapter to solder on the wire, so I will be using it as is. Which do you think would give the greater gain, a parabolic-style one or a cantenna-style one?

Thanks a lot for all of your help.

a parabolic dish intercepts RF on a large surface area and bounces it back in phase to an antenna element at the focal point. this presents more power to the antenna element

cantennas are bogus. cantennas intercept RF through a very small aperture and reflects it in many conflicting phases to the antenna element.

you will note that NASA and other satellite users point parabolic dishes, not cantennas, at satellites.

You raised a good point about NASA using parabolic dishes.

However, I wouldn't totally write-off cantennas. I did fasion one from a Bushe's Baked Bean can, and it gave me a signal of about -80/82db from -87/89db. For me. that made a difference between not being able to connect and being able to.

I'm curious now, though, if a parabola wouldn't make it a little stronger/more consistent.

I guess that means more testing.

Well, I added another can to the antenna and found that it gives me a little better gain with a more stable signal. However, this has made it much more directional. That is, the performance drops off if you are not pointing right where the router is.

I'm thinking that the parabolic dish might be a little more forgiving when it comes to directionality.

I've been working on a project involving these two and I was just about to make a similar topic. I made a usb dongle cantenna and as it turns out, it makes a difference of about 5-10 dBm. I've found out through research that this was pretty typical. Nothing exponential. I also attempted to attach the cantenna to where the antenna would be on an old satellite dish. To make something like that work, angles are CRITICAL. Just as critical as the direction where you have to point the cantenna.