Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Simple Wi-Fi Yagi (2014)

ham-radio.com

Post reply on HN
Print view View original

21–30 of 70 posts

Re: Simple Wi-Fi Yagi (2014)

#21

Post by colanderman »

mediocrejoker wrote: post #16

This makes the antenna more directional. It increases the range in one direction while decreasing it in every other direction, so I'm not sure how well this would work for most people without relocating the router/AP. That being said, it's a clever bit of engineering.

Given that it's only somewhat directional, this would actually be useful for the common case that the AP sits in a corner of a one-story house. No sense sending all that RF energy outside, so direct it inside.

Re: Simple Wi-Fi Yagi (2014)

#22

Post by fovc »

mediocrejoker wrote: post #16

This makes the antenna more directional. It increases the range in one direction while decreasing it in every other direction, so I'm not sure how well this would work for most people without relocating the router/AP. That being said, it's a clever bit of engineering.

My current (rental) place has the router and AP in one corner of the apartment, so signal strength at the other end is terrible. Is there a better (cheap but effective) option than this?

Re: Simple Wi-Fi Yagi (2014)

#23

Post by colanderman »

grahamburger wrote: post #7
turbohedgehog wrote: post #4

Earlier quoted context omitted.

FCC regulations (afaik) only apply to the power output of the device, modifying the antenna like this shouldn't change the power output.

FCC regulates EIRP, which is output+antenna gain. For this to be strictly legal you would need to adjust the power down until the EIRP is within the legal limit. Actually to be strictly legal I think it would need to be type excepted by the FCC. That being said if you're using this in your home/office on a legal channel it would be really difficult to even tell from outside you were using it and almost certainly not…

To be fair, the FCC regulates both EIRP (4 W / 36 dBm) and max transmit power (1 W / 30 dBm). E.g. you can't just have a 34 dBm transmitter hooked up to a 2 dBi dipole.

Re: Simple Wi-Fi Yagi (2014)

#24

Post by cyanoacry »

fovc wrote: post #22
mediocrejoker wrote: post #16

This makes the antenna more directional. It increases the range in one direction while decreasing it in every other direction, so I'm not sure how well this would work for most people without relocating the router/AP. That being said, it's a clever bit of engineering.

My current (rental) place has the router and AP in one corner of the apartment, so signal strength at the other end is terrible. Is there a better (cheap but effective) option than this?

You can try adding a parabolic (or circular) reflector: http://www.freeantennas.com/projects/template/

As with the original link, the antenna is directional (and since it's a reflector, probably even more directional), so you lose out on flexibility. It'll be quite good if you don't plan on moving the other point, though.

Re: Simple Wi-Fi Yagi (2014)

#25

Post by colanderman »

fovc wrote: post #22
mediocrejoker wrote: post #16

This makes the antenna more directional. It increases the range in one direction while decreasing it in every other direction, so I'm not sure how well this would work for most people without relocating the router/AP. That being said, it's a clever bit of engineering.

My current (rental) place has the router and AP in one corner of the apartment, so signal strength at the other end is terrible. Is there a better (cheap but effective) option than this?

Better is to get a WDS bridge (wireless repeater). A high gain antenna (higher than in article) won't work well in the "long house" scenario because two clients may not be able to hear each other and may thus collide. (RTS/CTS is supposed to fix this but it relies on clients choosing to use it.) Unfortunately with WDS, the bridge must be the same brand as the AP (which itself must support WDS), so you might be stuck purchasing two new pieces of hardware.

But if the clients are all near each other, you have some money to spend (~$100), and don't mind being stuck with one band (2.4 GHz or 5 GHz), I'd recommend one of these:

https://routerboard.com/RBSXTG-2HnD

https://routerboard.com/RBSXTG-5HPnD-SAr2

https://routerboard.com/RBSXTG-5HPacD-SA

They're really meant for outdoor installations but they work well for indoors with a cluster of clients far from the AP.

Re: Simple Wi-Fi Yagi (2014)

#28

Post by stephen_g »

vinhboy wrote: post #26

So this makes the router sends a stronger signal, farther. But how does this help if my laptop still has the same wifi adapter and can't send a strong signal back?

It also makes the antenna more sensitive in the direction its pointing. The elements make the antenna more directional, sort of focusing the energy. This increases the transmit side by concentrating the energy into a smaller area, but the same effect also helps it collect more energy.

The trade-off is worse performance perpendicular to the extra elements.

Re: Simple Wi-Fi Yagi (2014)

#30

Post by kogepathic »

MayeulC wrote: post #29

As an electronics student, are there any resources I could use to learn the basics of RF (antennas, etc)?

1. Find a university course on RF, look up the course textbooks.

In my university we had several courses on "analog electronics" which covered topics like free space path loss and RF concepts (e.g. bandpass filters).

2. Use Google or another search engine (DDG) to find the book in PDF or EPUB version.

3. Enjoy reading the book without forking over hundreds of dollars to a greedy publisher.

Post reply on HN