Long Range Wifi Gear in an RV

So any self respecting geek is going to want internet access.  The average LTE plan is ridonculously fast anymore (I've seen 50Mbit down in rural areas) and feels like a home connection.  That's great but they are usually limited unless you are particularly crafty.  As a result most people tend to try to use wifi.  For many people this involves turning on your laptop, trying to connect and bitching that it doesn't work.  In parks that have park wide wifi with many repeaters this isn't usually the case.  Usually a tengo type park works but it's generally pretty slow.  I've found that it's often due to wifi congestion but sometimes the backhaul connection to the internet service provider is the problem as well. 

Just buy a better antenna

But in our travels we figured out quickly that there are MANY parks who have free wifi - in the office.  The best sites are generally not near the office.  We quickly decided to acquire some wifi gear.  The first was this (note ours is the older TL-WA5210G)

TP-Link CPE on Pole

TP-Link CPE and yagi on Pole

It is basically a weatherproof wifi access point built into an antenna.  It can operate in client mode or router mode.  The neat thing about this thing is that it avoids the huge signal losses that result from a long antenna cable.  It is 12dBi but it works as well as or better than a 15 or 16dBi antenna/router separate combo with even a very high end cable in the middle.  When you get this access point you get a long ethernet cable.  You plug this antenna into one side and on the other end is a power injector.  Then you plug the other end into your rv based wifi router.  It's just like plugging into a cable modem.  Because of the power injector you only have to run one inexpensive long ethernet cable and you can go HUGE distances with ethernet with no losses in signal or throughput whatsoever.  Every additional foot of cabling between a router and an antenna adds losses ordinarily.

The issue with this device is that it's a bit flaky.  We've even gotten a replacement and sometimes it just disconnects for fun.  It also can take a very long time to connect for seemingly no reason.  If you know the wifi is there, you see it in the scan and the signal is high enough, it will connect, but it might take 5-10 minutes.  The good part about this is that it has a signal strength meter on the back with LED's.  This isn't like a browser based signal meter.  It is instant and updates many times per second.  It really helps you aim the antenna precisely.  Sometimes moving the antenna one to two feet horizontally can make ALL the difference.

Yagi experimentation and mess

Another thing in my collection is a stack of MI424WR routers.  These are the actiontec routers that come with Verizon FiOS service.  They are dime a dozen and indeed these were given to me for free.  DD-WRT never worked on these routers so they always sat in a corner but I found out at some point I could install openwrt on it.  Why does that matter?  Well most router firmware can only act as a router.  That is your laptops can connect to it and it can serve you internet.  With aftermarket firmware you can almost always operate as a wireless CLIENT or bridge.  In that case the router becomes more like a cable modem that you can then plug into another router to bridge your short range wifi devices to a long range connection.  An MI424WR with OpenWRT is now my go-to for long range connection because it does go a bit further with this kit.  I have that router plus this antenna.  As a warning, it's fun to play with DD-WRT and OpenWRT on routers but it's incredibly easy to "brick" these routers.  A bad firmware flash is all it takes to kill them and they become unrecoverable without soldering a JTAG connector onto the board.  Still, if you don't pay a lot for it, and the revision you buy is supported, I highly recommend learning about it.

Image of Yagi WiFi Antenna 2.4GHz 15dBi H:30° V:25° Outdoor Directional Wireless N-female - TP512 ...
Manufacturer: Tupavco
Part Number: LYSB008Z4DNFC-CMPTRACCS
Price: $32.99

plus this cable

Image of AIR802 CA400FLEX White Antenna Cable Assembly, N Plug (Male) to RP-SMA Jack (Female), 25 Feet (7.62 m)
Manufacturer: Air802
Part Number: CA400FLEX-W-NMRSJ-025F
Price: $39.89

Note that this vendor is probably the only vendor on Amazon that doesn't allow returns.  You can choose to buy from him or if you want to maintain your options you can buy the TP-Link equivalent which is of acceptable quality but does have a bit more signal loss.  The vendor doesn't allow returns but the CA400 cables they make are quite good quality.  Note also that our cable is probably more like 12-15 feet.  You really want the shortest cable that can achieve your goals but don't forget to compensate for height as well as distance between router and antenna when measuring.

Image of TP-Link TL-ANT24PT3 3m/10ft N Male to RP-SMA Male Pigtail Cable
Manufacturer: TP-Link
Part Number: TL-ANT24PT3
Price: $19.99

Once upon a time we used this antenna

24dBi directional - It's huge

It looks cute right?  Like a mini satellite dish?  Hehe, it's massive.  A PVC pole is not even close to strong enough to hold it up and it really doesn't do much if at all better than the yagi I posted above which is much more compact and can stay on the mast while travelling.  In a permanent installation I'd consider the 24dBi antenna instead but we need to remain mobile so the smaller yagi it is.

Low interference - long range

Low interference - long range, thanks Mr. hotel

But why bother, why not just use the flaky TP-Link CPE I first discussed?  Well the issue with that is the firmware kind of sucks.  With openwrt you can see a lot more information about the access point such as the security type.  You can also run wireless tools like packet dumpers, etc on openwrt.  In general it just gives you more flexibility.  On the other hand the range isn't *quite* as long as the 12dBi CPE.  I often make use of both of them at the same time.  One connects to the wifi to download movies while the other provides browsing internet.  This works well on limited connections and allows us to use "double" our quota (okay not really since we are two people).

But I think before anyone outlays $50-$100 on wifi gear the question on everyone's mind would be how well does it work?  The answer to that question is well enough to use but not well enough to depend on.  If you try to do IT work on this connection you will start to look like a real asshole to your clients.  When Voip calls drop, screen sharing and presentations die randomly.  When you can't get into a client machine because the wifi is down right now, it's just unprofessional.  Indeed in a situation where you are trying to reach across a park full of other rv's things can get really interesting.  Whenever someone operates their microwave it is enough to disrupt the weak signal.  Other wifi interference across the park makes things bad too.  The final nail in the coffin comes from other users. 

Hidden node problem

The effect is called the hidden node problem.  Normally it's not too big of a deal with a bunch of household wifi users but on a long range directional link it becomes a big problem.  With wifi users must know of each others existence in order to help avoid interfering with each other.  Otherwise it's like two people with ear plugs both trying to talk to a third person at the same time without knowing when the room is quiet.

You see the antennas here have a gain.  Rubber ducky antennas are 3-9dBi.  The panel antenna in the TP-Link CPE is 12dBi.  And the satellite dish one is 24dBi.  What is gain?  It's not that this antenna boosts the signal.  In fact the signal is weaker due to cable losses.  Radio signals emit out from a normal antenna in a spherical pattern.  When you use a rubber ducky antenna it focuses the signal into a 360 degree pattern more like a Tourus.  The signal travels vertically far less.  This focusing of the power works both ways and allows further horizontal signals to be received and transmitted.  Because of the assist to both transmitted and received signals, this is helpful no matter what kind of antenna and router is on the other end.  The panel antenna and yagi focuses the signal much further, this time into a single direction.  The pattern is horizontal and directional in about a 30 degree cone.  Despite the fact that this is such a cone, precise aiming can still help you eek out better transfer rates.  The 24dBi satellite antenna must be fairly precisely aimed or else it simply doesn't work at all.  This can be useful for isolating interference somewhat (but honestly microwaves still trash the signal).

What kind of range?  Well take a rural environment like Illinois where there are vast soybean fields and you have line of sight to the building the router is in.  1.2 miles or so.  If there are any trees in the way you can't achieve more than a couple hundred feet.  If BOTH sides are cooperating (both are long range antennas, set to high power, pointed at each other), you can achieve many MANY miles.  In practice we can generally hit 500-1000 feet without too much trouble.  If they put the router in front of a window, much further.  If they have an outdoor antenna placed high up, MUCH further.

And what about these 1000mw high power usb devices like Alfa USB dongles? 

They are actually nearly useless.  Most routers communicate at 18dBm or so.  The thing about wifi transmit power is that it must be the same on BOTH sides.  Otherwise one side will be able to reach the other but not vice versa.  In effect your range is still limited to the transmit power of the weakest device.  Think about it carefully and you'll get it.  Another effect is that signal reflections and other issues can actually cause higher transmit powers to work less well.  Indeed I find that setting my MI424WR to 17dBm (instead of the 30dBm of a 1000mw transmit power) results in better signal.  Setting higher than this eventually stops working, I assume due to the transmitter overheating.  Perhaps better hardware can handle this.  The TP-Link CPE 12dBi panel antenna mentioned above works well at 27dBm - but it doesn't really seem to help range because as I said - it is limited to what the other side is set to.

Conduit Ladder Mount

So given what wifi is, if you still want to bother with it, these external antennas need to be mounted.  Our solution was to use metal electrical conduit and conduit hangars attached back to back to our ladder.  It works well enough but it can loosen up over time and cause the pole to drag.  That was the source of our one catastrophe.  Also in case you're wondering, mounting the antenna or CPE on a long pole very high up almost always improves signal unless there are a lot of trees.  Then often you can get a better signal at ground level because there are fewer leaves. 

Dragged Pole

The final elephant in the room here is whether or not all this is worth it.  I'd say about 40% of the time it works without trouble and about 60% of the time I struggle with it and spend hours tinkering with it.  In fact for most people I would say that this stuff is an absolute total waste of time.  For the average person I'd say an LTE plan and a Wilson Sleek 4G is all you need.  I think the Botts of http://www.outsideourbubble.com (who I hope we can call our friends, we had the distinct pleasure of hanging out with them at the Grand Canyon) have it right in terms of wifi gear.  They use a Ubiquiti router (I think a Bullet) connected to a permanently mounted Omni antenna on their roof.  No tinkering - either you have signal or you don't.  Takes 5 minutes to check.  No directional aiming or other business.  Kind of like Solar panels for someone that doesn't boondock year round.  Economically it is completely nonsensical.  When you can acquire a super quiet inverter generator from Costco that can recharge your batteries or run your microwave for $600 that will run for 10 hours on 1 gallon of gas producing 15kwh in the process, solar panels start to look a little insane.  The average 600watt setup won't produce that lab rated power in the best of circumstances and the amount of time it even gets close is just a few hours per day.  Such a setup generally costs thousands once you have solar controller, cabling and installation costs settled.  I'd argue solar money is much better spent on additional battery capacity.  That can really improve your quality of life only having to recharge every few days.  The point is that it's fine if you have fun playing with this stuff, but if you're just trying to get online, get some work done or download some movies it can get very frustrating and time consuming.  From a simple time perspective, say you earn $50/hour doing your work.  If you spend 4 hours a month that is $200 that you could instead spend on an additional bad-ass verizon LTE plan that will work better than ANY campground wifi nearly anywhere you go.  Every now and then this fact rubs me the wrong way but then I realize I didn't want to actually work anyway, and the alternative is just sitting around and doing nothing.  Often this wasteful tinkering has made me money in the end anyway.  One of my clients had me set up a long range wifi network between a few of his convenience stores cutting out some big FiOS bills for him.  Then there is the other thing too that if you spend 9 months out of the year somewhere as we now have to because our son is in school, hitting free wifi can save you a lot of money and the time spent on the initial tinkering becomes worth it.

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