Selecting an outdoor AP
From IPTrains
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In a nutshell
The WiFi access point is the single most critical element of the system from a video performance standpoint. We need the AP to be weather proof, support POE and have as large a coverage area as possible. Most outdoor APs cost far too much money for hobbyist use ranging from several hundred to several thousand dollars. The good news here is that the Wireless Internet Service Provider (WISP) industry has recently driven the price way down on high quality Customer Premises Equipment (CPE), wireless units that can be used as outdoor APs for our purposes.
We offer two models of outdoor AP, both from Ubiquiti, the Loco2 and the Pico2, both at very affordable prices. Below we will discuss general outdoor AP requirements in a bit more detail and then provide selection guidance for the two APs that we offer.
Weather proof
This is the single most important consideration. It is possible to put an indoor unit in a NEMA box and use it outdoors but it is both expensive and unreliable. We know, we're past masters at the art. Our APs are designed for 24x7 outdoor use in any weather conditions.
POE equipped
This is a biggie. Power Over Ethernet (POE) allows you to provide DC power for the AP from indoors, over the same CAT5e cable that you will use to connect the AP to your home network. POE is both safer and more convenient than trying to supply AC power outside to an AP power supply. Both our Pico2 and our Loco2 include POE injectors and power supplies. This can cost quite a bit if you have to add it on to a third party Access Point. Both of our APs run native POE, there is no local power jack, the power comes in across the Ethernet cable.
Coverage Area
Not all AP's are created equal. Coverage area is a factor of receiver sensitivity, antenna subsystem design and processor multipath detection/rejection. A large scale garden railway is a tough RF environment, the trains are close to the ground and there are a lot of objects that will block or reflect the signal from the train. The very best AP for this type of hostile radio environment is one with a Omnidirectional antenna like our Pico2. It adapts as the trains move about the layout to always give you the best signal.
Size of the coverage area (the layout) is an important factor in AP selection but not the most important. The most important is the topology of the layout. Garden railroads with lots of terrain features, hills and mountains and tunnels, will need the power of a Pico2 AP. Railroads with fewer RF obstacles can often get by with the cheaper Loco2 AP. We have successfully used the Loco2 AP to cover an area of 3200 square feet (80x40) however this area is pretty flat, there are no tunnels or large dirt mounds to obstruct the signal and only a few major trees. This same AP can 'see' trains on the entire layout (an area of 8000 square feet, 80x100) however it does not do as well in areas that are 'masked' by mountains and hills and does suffer more dropouts than the Nano2 when the train is in 'tough territory'.
The Pico2 also does a better job of 'back lobe' coverage. That is, covering the area behind the AP. The Loco2 'sees' better in front of the AP. If you are using a Loco2 we recommend mounting on the edge of the coverage area, a Pico2 can be mounted in the center of the coverage area which can be very useful to 'see' down into hard to reach areas.
For very large layouts, those that exceed 500 linear feet (as the crow flies, Line Of Sight [LOS] distance from end to end) then you can use a pair of Pico2 APs, one at either end of the layout, both operating on the same WiFi channel and allow the trains to 'roam' between them. Depending on terrain, a pair of Nano2s can cover up to 1800 feet on an LOS basis.
We are always happy to provide advice on coverage and we also consult professionally in this space and can prepare heat maps and RF coverage maps, installation guidance, etc.
Trouble shooting tools
Our Ubiquiti access points have a full suite of built in tools for trouble shooting and performance tuning. You don't always need these tools but when you do, they are a life saver. Transmitting multiple video streams from moving locomotives is a technically audacious task, it's extremely useful to have the right tools handy when a problem crops up. Our APs support individual station dynamic RSL measurement, continuous throughput measurement, frequency survey, etc. They also have a very wide range of configuration settings to allow us to work around interference and other issues. Bottom line, if you use one of our APs we will set it up for you here and will be able to support you fully. With third party APs, we'll help with the basics but the advanced stuff is on you.
Summary and recommendations
We went through a large number of APs during our development efforts. Our shops look like an AP museum because we have so many of the blasted things. A good external weather proof AP with POE can cost many hundreds to thousands of dollars, go price them and report back to us ;-) Our Pico2 costs well under $100 and does all of the above, superbly.
The Pico2 is the right choice for large railroads with tough terrain and multiple units sending video on the move simultaneously.
The Loco2 is a newer AP and we have less experience with it however we are comfortable with recommending it for smaller layouts (up to about 4000 sqft) that don't have a lot of demanding terrain. The Loco2 is also an excellent and inexpensive choice for use with our wireless track side video units. Since they don't move around like the trains do they are much less demanding on the AP and a Loco2 can handle multiple track side units at rather large distances.
The Loco2 is not really up to providing video from a moving train if the layout has a lot of 'clutter' (tunnels, hills, trees, etc.) and is fairly good sized. The Pico2 can handle one train pretty well on a large cluttered layout.
A pair of Pico2s can handle several trains in that situation.
Bottom line, if you can find a better outdoor AP than either the Loco2 or the Pico2 for the money, buy it. We are not in the business of selling APs, they are not a profit center for us, we offer them only to provide you with a complete and tested system that we know will perform well. The only caveats I will put on the use of a third party AP (other than the fact that we set the AP up for you so that it is plug and play) is that we can only provide limited set up and troubleshooting help with third party APs since not all APs have the appropriate diagnostics needed to perform interference and performance troubleshooting. Also, our AP runs Linux, and we do have plans to take advantage of that with future offerings. If you use one of our APs we can work with you up to the point of logging into your AP to help with troubleshooting, interference de-confliction and performance tuning since our APs have a full tool set that is accessible both via the web and via ssh.
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