Community Forums

Logthumper · 12-27-2010, 09:09 PM

Which WiFi antenna will perform better under same conditions and why?
14dBi Yagi
14dBi Omni

Thanks

Retired and Happy · 12-27-2010, 11:54 PM

The most immediate point I see is that the yagi would have to be pointed toward the signal source for max efficiency. I don't recall enough about antenna theory to remember what an omni antenna might look like, but I'm imagining it would have to be larger than a directional antenna of equal gain. The advantage would be the omni pattern, no changing directions needed.

There. Now others have something to shoot at.

John Hilley · 12-28-2010, 07:59 AM

The main advantage of the directional Yagi over an omni with the same gain is the rejection of other signals and noise. The higher the differential between your signal and the noise level the better the signal.

whem2fish · 12-28-2010, 08:31 AM

the 2 yagi i run have a beam cone of 30 deg i use them with a links n router one on house the other about 1/4 mile on garage on back of my property they are pointed at each other
that said if your park has wifi and you get a weak signal it probaly help
dave

f14av8r · 12-28-2010, 09:44 AM

The specified gain (dbi) of the yagi is at the center of the directional cone. The omni would give the specified gain over 360 degrees of the compass. Rejection of noise / undesired signals is a definite advantage of a directional antenna but you'll also spend some time trying to determine the proper position to capture the desired transmitter. That's not a problem when you know where its located but it could be a pain in an unfamiliar campground.

Logthumper · 12-28-2010, 09:02 PM

Thanks for the replies.

Wayne M · 12-28-2010, 10:01 PM

IF all conditions are equal, the Yagi should outperform the Omni. Using a field strengh meter should show more gain with the Yagi than the Omni. That being said, it is more difficult to position the Yagi so that there is no lose of signal. If you are talking miles, the yagi will outperform the Omni when correctly orientated. The Omni is the easier to set up and if you are just talking within a campground, the Omni is the better choice, not having to fool around making sure the direction is correct. (think setting up a portable satellite antenna when using a Yagi)

Logthumper · 12-28-2010, 11:18 PM

Thanks again.
Some info as to why I asked the question.
For normal use, I use the ALFA 1000mw USB Adapter with the 5dBi antenna.
When that doesn’t work I use an externnal 8.5dBi Omni raised high above the RV.
When needed I use an external 15dBi Omni raised high above the RV.
So far I have always achieved WiFi connections.
However my wife has been bugging me as what to get me for my birthday. So since I have not experimented with one I suggested and she ordered a 14dBi Yagi (remains in the box until Jan 5).
I have also downloaded DD-WRT to a Linksys Router I had laying around and so far just playing around with it working as a Repeater it appears to work great.
Just dinking around for now, waiting until spring when we can once again get on the road.

wa8yxm · 12-29-2010, 01:55 PM

The Yaga is more resistant to noise coming off the side or rear.. If there is someone running a Mi-Fi or other router in the area who is inconsiderate enough to park it on the same channel as the park's router it may reject that interference

That said.. You have to point it at the router's antenna.

Now; If you should choose the OMNI, and find that it needs some help either in interference rejection or some more gain.

RV Road Trip Library - Do-It-Yourself Wi-Fi Signal Booster

Actually works.. I built mine using some advanced materials (I used a plastic sheet for the reflector (Covered with aluminum foil) and wood for the "Bracket" instead of card stock.. It shows an amazing front to back ratio. I also blew it up some (you can scale it up or down)

SCVJeff · 12-30-2010, 12:33 AM

Don't forget that this is not a simple point to point voice communication. There is way more going on than just talking between you and the CG Wifi. These comms are automatic and the conditions of who gets to transmit at any given time is set by the host, but also the client will hold off packet transmission if it hears it will be jammed by another carrier on channel. There are potentially many other clients trying to talk to the same host (the CG WiFi) that if they cannot hear you will just transmit over you, effectively jamming both you and your neighbor attempting to talk to the same host, or worse, several WiFi hosts. Omni's may hurt or help, but it totally depends upon your position with respect to the CG Wifi host and those trying to talk to it.

Logthumper · 01-04-2011, 03:36 AM

Most WiFi Hotspots are probably using a Omni antenna. When using a Yagi antenna to connect to an Hotspot using a Omni antenna, does it make any difference which way a Yagi antenna is mounted, vertical or horizontal? Would this also be true if the Hotspot is using a Panel antenna, Yagi vertical or horizontal?
Thanks

patmsp · 01-04-2011, 05:15 AM

I use Verizon broadband. I currently have a omni antenna and it works fine. My local broadband network is 3G. Sometime in the future it will be upgraded to 4G (a faster broadband). It is at a higher frequency. The omni will not work on the 4G network and I will have to upgrade. The 4G external antenna is NOT a yagi, but it is directional and will have to be pointed to the source.

Pat

Logthumper · 01-04-2011, 08:16 AM

Thanks Pat, but my question relates to WiFi Hot Spots, not Cell Phone 3 or 4G.
Thanks again for your help and info.

vermilye · 01-04-2011, 08:59 AM

Technically, you want to keep the same polarization as the base station antenna, so the yagi should be mounted vertically to match the polarity of the omni antenna.

Practically, you probably won't see any difference. When the frequencies get high enough, matching polarity becomes more important