Making Antenna Visual Alignment & Placement Tools
For a PDF version of this document including graphics and photographs –Making Antenna Visual Alignment-Compressed.
For the PDF version of the page to print –30° and 60° for Visual Antenna Alignment Tool.
For a sample printable PDF of a Protractor –conventional-protractor.
For a high-density stadium project I was working on, I needed a way to visualize the coverage patterns and interference patterns of some newer 30° highly directional outdoor antennas.
I first thought of using 3D computer modeling software. But didn’t have access to, or experience with such software. Nor did the customer have the time or money to spend on such high-tech tools
The customer just wanted their Stadium Wi-Fi to be designed, installed and working for the start of their season, mere weeks away.
Since “Necessity is the Mother of Invention” – I had a need, and so went about inventing a solution to meet my immediate needs.
I needed to be able to ‘see’ the coverage patterns of this 30° antenna, as well as ‘see’ the 60° area of interference each antenna would have. This would be a main part of designing the coverage, and also the interference zones would help in the channel planning to attempt to keep Co-Channel Interference at bay… well at least for the 5GHz frequencies as much as possible.
I tried visiting office supply stores, online architectural supply sites, and even some photography and astronomy sites. But nothing available met my specific needs.
After a couple of humorously bad failures, I eventually came up with this PDF template and process to build my own tool out of simply paper and tape.
In practice it works very well indeed. I’ve now used this technique on many installs to help in the WLAN design process.
You will need to print out at least four copies of the first page of the PDF. This has been designed to print on either 8.5” x 11” or A4-sized paper.
Additionally, you will need:
- a pair of scissors
- a straight-edge – like a ruler
- transparent tape.
Cut off the ‘tails’ – the sides for a larger 60° tool. In this first process we will be constructing a 30° tool.
Using the straight-edge, fold both sides at a 90° angle.
You will need to make a total of 4 of these ‘u-shapes’.
Tape one of the ‘u-shapes’ to another one, lining up the sides.
Repeat for all four shapes.
Fold into a ‘cone’ and tape the final sides together.
You can cut off the spare material on both ends.
The completed device looks like this.
This can be folded to fit inside a notebook or file folder for easier transport.
To use – look through the end.
The goal is to be able to ‘see’ where the 30° pattern covers. By holding this tool to your eye, while standing at various potential Access Point locations, you can measure on the ground where the coverage pattern is.
I normally carry a floor plan of the site and mark on the map where each coverage area reaches.
To visualize the 60° interference area, you’ll need a wider tool. I first made wider version of this same type of ‘cone’ – using the wider tails on the PDF. But it makes a fairly large device that is more wieldy to carry around.
Instead, I found if you flatten the 30° tool, it becomes a 2-dimensional 60° tool. You can use it to check the vertical, and then horizontal interference zones just like you did with the 30° but instead of looking inside of the tool, you look over the top and to the sides of the tool. Not quite as simple, but it does in a pinch and you only need to carry a single tool with you.
I hope this might help others with needs designing around 30° antenna patterns. You can easily take this technique and build other tools to meet the specific requirements of the highly-directional antennas you are using in your high-density Wireless LAN designs.
If you come up with other designs, I’d love to hear back from you.
Keith R. Parsons