Using the Asus Eee Slate EP121 for Site Surveys
I recently acquired an Asus Eee Slate EP121 to trial for site surveys. I have been looking for some time for a light PC to replace my old Atom based Netbook for site surveys and was pleased to see that the tablet frenzy from the iPad introduction last year had resulted in more choices available in the market. My main argument for wireless professionals is that there are really two different tasks they need a PC for. First is they need a general purpose PC to use for tasks such as writing up reports, reading email, setting up APs and controllers and of course surfing the web. This more general purpose machine is really not too different to what most engineers use daily to get their jobs done. The second set of tasks that a wireless professional needs a PC for is to basically walk around and do site surveys, RF interference analysis and troubleshooting of WLAN issues. Its this second set of tasks I would argue that requires a light machine that is easy to carry but is still powerful and flexible enough to process the data gathered as part of those tasks. I must admit to not seeing the usefulness of a pen and tablet for these tasks before and that the pen can also extend to note taking in the field (more on that in a moment).
The Asus Slate I acquired has the following specs;
- Processor – Intel Dual Core i5-470UM 1.33GHz
- Screen – 12.1″ 1280×800 AFFS+ Capacitive Touchscreen
- Memory – 4GB DDR3
- Storage – 64GB SSD
- OS – Windows 7 Home Premium x64
- Battery – 34W/hr
- Ports – Mini HDMI, 2xUSB 2.0, SD Card, Mic
- Weight – 2.53lbs
- Wireless – Bluetooth 3.0, 1×1:1 2.4GHz 802.11n (Atheros AR9002WB-1NG)
- Other – 2MP Camera, Wacom EM Digitizer, Bluetooth keyboard, Folio case, Wacom EM Pen
To the above I have added several accessories that I needed for site surveys and to make the tablet more useful to me in the field;
- Energizer Energi To Go XP18000 (18000mAh)
- Rocketfish USB hub
- Shoulder Strap
- Air Magnet Spectrum XT card
- D-Link DWA160 (for Air Magnet Survey)
- 6′ long power adapter cable (Radio Shack)
As you can see from the above picture, I have the tablet attached to a shoulder strap to make it easier to carry. This takes almost all of the weight off my arms and additionally provides a way of resting my hand on the strap when I am making survey marks on the tablet as I walk around. This avoids a problem I discovered the first day I was using it where when I rested my hand on the screen to make a mark the screen misinterpreted it as a finger touch and marked the location where my hand was on the map. The folio cover does not come ready made to have a strap attached to it, so I went to my local hardware store and got some grommets to make a durable hole in the case to attach the strap I had from another bag. I also needed a way to attach the USB hub. This was very easy as the material on the inside of the folio case worked well with a velcro strip I just attached the hub with that. I carry the spare battery, water, camera and other small supplies to keep me going in the secondary case.
The above picture shows the tablet running Air Magnet Survey. As you can see the large screen provides enough space to show all the main parts of the AM Survey interface without cramping it at all. My previous survey netbook was 1024×768 on a 10″ screen, which almost always resulted in not being able to see the whole of the map and the interface being squeezed down.
Here you can see the Air Magnet Spectrum XT software running. As I mentioned above my previous netbook would squeeze the screen down and I was only able to see the FFT graphs from one frequency at a time on the screen. With this screen I am able to comfortably see all the 2.4GHz and 5GHz frequencies and any interfering devices that are detected. You will notice also that the external battery pack is quite small (about 1lb).
I additionally have Microsoft OneNote installed on the tablet and found that this actually makes for a great way to take notes while I am out in the field doing surveys as well. Basically, as I survey I like to take photos and note things down I observe as I walk around. OneNote is just perfect for this task, even converting later my scrawl to typed words. I went to check up the other day on an install that was being done at another site and found that the PDF software I had could be also used to mark up with the pen and make notes as I walked around checking things. Really it was like having a portable notepad to walk around with.
Pluses to the tablet as a survey tool;
- The tablet interface is really really useful for surveys and note taking as you do the survey
- The performance of the tablet is on a par with recent laptops and can easily double as a normal PC with the bluetooth keyboard and a mouse
- Weight is good, still heavier than other smaller tablets but its the tradeoff for the larger screen
- Nice big screen with good resolution
- Well thought out hardware design with well spaced USB ports and SD card to expand storage
Minuses as a survey tool;
- Can sometimes have problems with your hands making survey marks
- Very weak battery life (2 hours max with the above setup)
- Heavy if you are just holding it for several hours in your hand
- Screen is a bit too reflective in sunlight although still visible for outdoor surveys
I have been looking for some time for a way to make my survey’s both easier to do and more efficient and I believe that a tablet based PC with a digitizer pen makes a huge difference from a standard laptop in reaching those goals. As mentioned above I found ways to get around the major weaknesses of the Asus Slate for this purpose and to me having a fully-fledged PC for surveys (with i5 processor) makes a major difference in the field. There are other, purpose built PC tablets that overcome the weaknesses of the Slate (such as Motion Computing’s line) but these tablets are often significantly more expensive.
My conclusion now having spent some time using a digitizer for input during a site survey is that it is far superior to using a mouse for input of survey marks during the survey. Although I could get by with mouse input, its just far quicker to be able to use a pen to mark on the screen where I have walked and this makes my surveys much more efficient. Add to this away of carrying the tablet that avoids tiring your arms and the only thing you have to worry about is getting tired from walking all day long! The major issue with the Asus Slate is its weak battery life, but with an external battery pack this issue disappears. I would recommend this tablet to anyone looking for a reasonably priced and powerful Windows 7 site survey platform.