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Choosing the right WIFI antenna for your RV

December 19, 2017
Yagi Antenna

My WIFI setup for the trailer is a Linksys WRT54G running DDWRT with power turned up to 200mw.  I have DDWRT configured as a Universal Wireless Repeater, which allows it to automatically connect to free WIFI and repeat the signal.  One antenna port has a 6ft run of LMR-200 antenna cable going out to the roof of the RV.  This antenna cable has a loss of about 1db.  The other antenna is the original OEM antenna.  Typically the original antenna is what the devices in the RV connect to and the one outside is used to connect to campground or other free WIFI.   The two antenna used outside for the test were a 5 dbi Outdoor Omni Directional 1/4 wavelength antenna and a 25 dbi Yagi Directional antenna.   You can see my previous post on how I did the original setup.

I did my testing in my driveway as the subdivision had a significant amount of different WIFI networks at varying distances to test against.  I started by making note of a number of SSID’s that were in the -70 to -100dbi signal range when using the original Omni directional antenna.  Once past -70dbi, generally WIFI is unstable to unusable so being able to improve the signal of these SSID’s using the Yagi antenna would potentially make it useful.

After collecting the information on the SSID’s I then switched to the Yagi directional antenna and retested.  The only difference with this test was that I had to rotate the TV antenna a few degrees each time to find each SSID.  A typical Yagi directional antenna only has a useful range of about 15 degrees to be able to aim.  Other types of directional antennas like Panel antenna are able to pick up a much wider area and with an Omni directional antenna it is able to pickup a full 360 degree range.  The wider the range the less the antenna is able to pick up weaker signals.  Having a narrow range also made it so I could pinpoint the specific house that each signal was coming from in order to gauge the distance.  In all cases the signal came in about 20 dbi stronger on the 25 dbi Yagi antenna than the 5 dbi Omni directional antenna which is the expected result.  This meant that any signal that the Omni directional antenna was able to pickup that was in the -90 to -71 dbi range would be amplified up to a usable -70 or better.  The SSID’s that were beyond -90 dbi were still stronger with the Yagi but not within the usable range.

The conclusion that the Yagi antenna improved the signal was not a shock to me.  There were two things that I had not really considered.  The first was that the SSID’s that were in the -90 to -71 dbi range were only about 100m farther than the SSID’s that the Omni directional antenna was able to receive at -70 dbi or better.  That was much less usable range increase than I had expected.  The second thing I had not anticipated was just how much of a pain it was to use the Yagi.  When going camping, I would not want to spend a half hour or more aiming the antenna to find and then tweak a usable signal when I could just crank up the Omni directional antenna and have a decent chance of picking up WIFI in a few minutes.

The final thing to consider is that campground and other public WIFI is really not that good to begin with it, so I decided it was not worth the extra time aiming to get a stronger signal on a really poor WIFI network, because my internet would still be slow.

 

Adding a WIFI and a Cellular Amp to my RV

5 dbi Omni Directional Antenna

 

Directional Antenna

25 dbi Directional Yagi Antenna

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From → RV Tech

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