Refinement of the APoS Survey Tripod
I have used numerous combinations of tripod, battery pack and PoE injector during my time carrying out "Access Point on a Stick" APoS design and survey work.This post will cover the noteworthy tripod & battery configurations I have tried so far, ending on a high note with my current (as of July 2016) solution. (Skip to the end if you are only interested in the latest and greatest configuration)
#1 Speaker Tripod
Initially, provided by my employer, a traditional speaker tripod, reasonably cheap, very robust and stable.
This style of tripod has a large foot print, this provides good stability when deployed, however with this wide leg span it was necessary to collapse the legs when moving between most AP locations. Even when fully collapsed the tripod is bulky, this did not present a major problem at the time because it packed neatly into a Peli Case. In addition to an AirCheck, 3 or 4 APs, PoE injectors, spares, tools, bits and bobs... the works.
Speaker Tripod - AP Attachment
The AP attached to the tripod with a T-Junction, allowing for a short outcrop onto which the AP mounting plate, Cisco in this particular case could be fixed with the use of the suspended ceiling grid clips and jubilee clips.
By cannibalising another tripod of this style the outcrop is capped with a rubber foot, hiding away the bare metal edge.
This particular speaker tripod consisted of three pieces
Speaker Tripod - Specs
Basic specs I captured regarding this particular APoS tripod
Speaker Tripod - Battery Rig
During the time I used the Speaker Tripod, I used a Terrawave Battery, carried in a camera case with a straight ethernet cable, slung over my shoulder when moving between AP locations and place the battery bag on the floor whilst the tripod was stationary.
#2 Manfrotto - Ranker Stand, 1005BAC
A year or two later, Mark Julier suggested and provided me with a Manfrotto tripod. The Ranker lighting stand.
This tripod is a different animal altogether. The Manfrotto weighs less, is less bulky and looks more professional.
Ranker Stand - AP Attachment
One of the most significant features of this tripod is the top attachment.
This tripod is a lighting stand, these are widely used in the photography/film industry, the top attachment is in my words a "multi-angle spigot receiver" with screw fixture.
To date this is the most simple and effective top attachment I have used.
A short length of pipe or cannibalised leg section from a microphone stand, allowed me to create an easily removable AP attachment outcrop.
- The Manfrotto looks more professional
- A Manfrotto branded carry bag is available
- The centre column tubes are air dampened so that when you release the centre column locks the AP descends in a slow controllable manner
Ranker Stand - Specs
These basic specs available on the Manfrotto Ranker Stand product page
Ranker Stand - Battery Rig
With this tripod I primarily used a Tracer battery with a LigoWave PoE injector. With the use of a generic bicycle handlebar phone mount it was possible to attach the battery and PoE injector to the base of the tripod centre column. This increased the unit weight but resulted in a single unit to be carried around site.
Ranker Stand - Summary
This setup served me well, however after completing the walk of a given area, I would still need to lower the AP and retract the tripod legs so that I could pass through doorways with ease, then reverse these actions for the next AP location.
For me this was a very good solution
there was still wiggle room for improvement.
#3 Craig Smith ‘Wheely Good’ Survey Tripod
In July 2015 I was asked to assist a colleague performing an APoS on site WLAN design in a care home environment. Health and Safety regulations stated that two members of staff would be required, one person to monitor the tripod, the other performing the walk around with the laptop.I had heard about Craig Smith's Office Chair Wheely base Tripod, but I had not seen it.
The Office chair wheely base tripod looked a little MacGyver built, but this is no bad thing!
- Wheeled office chair base
- Painters pole centre column
- Painters Brush attachment at top for AP mounting
- PointSource battery with rest plate at base of centre column
I was blown away by how easy this system made manoeuvring the AP around the customer's site. This played on my mind during the weeks following and I began researching wheeled lighting stands / dollies, so that I could make my own.
#4 Background Light Stand
On eBay I discovered a folding leg Photographic Wheel Stand Tripod intended for background Lighting / camera flash mounting.
I purchased one of these and increased the height by replacing the stubby centre columns with much longer poles from B&Q (the local hardware store). These poles came from the curtain pole section.
The AP attachment for this tripod was not fantastic, I manufactured this myself by butchering another microphone stand leg, pushing the spigot that came with the dolly stand through the outcrop, then secured the two with a threaded hole into the spigot. This was acceptable until the AP descended too quickly on one occasion, stressed the joint and resulted in the elbow becoming loose.
While the AP attachment was not fantastic, the mobility this tripod offered was excellent. With the battery and PoE injector mounted low down on the centre column the balance improved and when stationary did a great job. I acknowledge that the components used in this configuration are a little on the cheap and nasty side, as a result the final look is not as professional as the Manfrotto.
Background Light Stand - Specs
Background Light Stand - Summary
The leg span was slightly too small, making the unit prone to tipping if knocked, fortunately this did not happen to me, but it was a concern. The AP mounting solution left a lot to be desired. However this rig categorically proved that an APoS tripod with wheels, that did not require retraction and expansion of the legs between each AP location was radically more efficient and worth pursuing further.
#5 The Apex Design - Manfrotto Tripod (Modified)
After some time, I decided that the Manfrotto Ranker Stand was the best tripod for the job and that it could be modified in order to achieve the functionality I desired.
It would be possible to reduce the leg and spreader strut length in order to allow easy movement through doorways.
It would be possible to add dolly wheels to the tripod, Manfrotto manufacture "Studio Wheels" for this very purpose!
With the wheels attached, position locked and the tripod collapsed, the unit will stand by itself.
Modified Ranker Stand - Specs
Modified Ranker Stand - Summary
This tripod configuration has served me very well for over a year of Wi-Fi survey work, without me being able to think of any genuinely worthwhile improvements or tweaks! I am satisfied with this configuration, so much so, that I wanted to share the idea with you.
Now… this does NOT mean that further improvements to the rig are not possible. I think the guys at WiFi Stand are making a product that looks great, it would introduce greater stability into this configuration and add extra height.
Build your own Modified Ranker Stand
The individual steps I took to modify the Ranker stand are detailed in this article:
Build Your Own APoS Tripod: Manfrotto Ranker Stand Modification Guide
#5.5 The Apex Design - Battery Rig
The initial method I used to attach the Tracer battery and LigoWave PoE injector to the centre column of the tripod was not elegant and required time spent faffing with a ratchet mechanism.
After many... many... cumulative hours spent googling, spread out over the period of several months, I found what I was looking for. A product that would perform the task in an elegant and professional manner.
- 2x "Stem/Bar Bike Mounts" from Quad Lock
- 1x "iPhone 5/5S/SE Case"
- 1x "Universal Adaptor"
Rather than bicycle handlebars I attached the bike mounts to the centre column of the Ranker Stand using the included rubber bands.
The PoE injector was fitted with an universal adaptor, the included 3M sticky patch weakened after a few weeks of use, so this was then bonded using super glue / araldite.
I did not feel comfortable using glue on the rubber case of the Tracer battery. Opting instead for a more temporary attachment method of strapping an iPhone case to the battery with two strong silicon (rubber) bands. I bought these from Amazon - Grifiti Bands.
Attaching the PoE injector and Tracer battery to the modified Ranker Stand.
Battery Rig Summary
Previously posted article on the battery and PoE injector
I have been using a 12v 10Ah Tracer Battery, this is a Lithium Polymer battery, that I bought from Amazon UK, I recommend exploring their product line because there may be a more suitable sized battery for your specific use case. Keith Parsons spoke to me at WLPC_EU 2016 in Budapest about the use of LFP batteries which offer some advantages over LiPo technology.
Previously posted article on How to make your own stretchy PoE ethernet cable
It is worth noting that the stretchy PoE only ethernet cable will only provide power to the AP, this equipment setup will NOT allow data. For example if you wanted to attach an Odroid iperf server to the the tripod for APoS throughput testing you would need to use a different ethernet cable.
If you decide to invest in any Quad Lock products as a result of this article please consider using this 10% discount Quad Lock Link, this will results in a 5% kickback to me, but honestly, I am only showcasing their product here because I like the functionality of their product.
Bill of Materials
The costs of these items vary over time, I am listing a rough guide price similar to that which I paid, not necessarily what they cost today.
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Thanks for checking it out.