Dear GLAMOS friends,
in this step-by-step tutorial we will show you how to utilize GLAMOS Walker and GLAMOS Walk App to test different antennas and find the best one.
Antenna is one of key components in your LoRaWAN and Helium setup. Antenna is a metallic structure that converts current flow generated by hotspots (gateways) or sensor devices to electromagnetic waves, and vice versa. So, it captures and/or transmits radio electromagnetic waves.
Understanding important antenna parameters and specifications helps to choose the best antenna solution for your application. Here are some parameters that affect how antennas will work:
All these parameters are affected by antenna design, materials and production technology.
Task of engineer or technician is to find best antenna for specific application. He needs to take in account parameters like:
Today, we will make real field testing to find which antenna best fits for our location. We want to get results what antenna fits our needs, how many hotspots can we reach and can we make some improvements in out setup. Testing will be done with 6 different antennas on 1 location.
Walker has SMA female connector and need SMA male connector on antenna side (not RP-SMA male). Difference between SMA male and RP-SMA male is that SMA male has needle in the middle and RP-SMA male don’t have needle. So for bigger antennas we will use N-type to SMA male adapter/cable.
From now on we will use indexes.
When we say “antenna type 4” that will be same as we say “antenna with 4 dBi gain”.
When we see in Walk App “Antenna: 2”, we will know it is “antenna with 2 dBi gain”.
When we attach antenna with 2 dBi gain on device, we will set up parameter “Type 0” in device menu.
|Frequency band||Spreading factor|
There you can see all your messages from beginning.
Notice Columns Position and Antenna. These are indexes we’ve set in Parameters of device during testing. Value “0” in Antenna column means that message was sent with antenna type 0 attached (that is 2 dBi antenna in this case).
Value “1” in Position column means that message was sent from our location number 1 (that is balcony in this case).
We can analyse data in Table, row by row. We need to compare number of hotspots (gateways) and signal quality (RSSI and SNR) for each message (row) and for each antenna.
To help you make testing faster, we developed Analytics tool.
In Overview tab you can see general data about number of sent messages, efficiency and number of reached hotspots. At bottom, you can find result of our advanced algorithm what antenna is the best based on our testing.
The best antenna of our testing is antenna Type 4 – that is antenna with gain of 5.5dBi.
In Antenna comparison tab you can see comparison of all antennas.
Reason why Antenna 4 is the best is that it reached 191 hotspot (gateway) in total, or in average 139 hotspots per each message. That is 23% better than Type 3 and Type 5 which are almost the same.
Type 4 also has the best signal quality (RSSI and SNR) compared to others (more positive is the better).
Worst antenna is 10cm long 1 dBi antenna which reached just 9 hotspots, or average 5 hotspots per message.
On graph are showed lines of Average RSSI for each message. So if 100 hotspots received message, average will be calculated from 100 RSSI values. If we take a look on graph, we can see that Type 4 is not far from Types 3 and Type 5. But we need to know that Type 4 antenna collected 23% more hotspots per message and that were hotspots with lower signal quality (they are far). That degraded final value for Type 4.
If we turn on “gateway count” in graph legend we can visualize how number of hotspots is changing for each message. We sent 40 messages with antennas Type 0 and Type 2 and because of that we have more bars.
Analyze by gateways tab offers us overview of connection between our Walker and each hotspot.
This allows us to see how some specific antenna communicated with specific hotspot.
In this example we can see that Type 0 had huge oscillations of signal, while Type 4 surpassed all other.
We can also analyze each hotspot (gateway) for each of our antennas. This can help us to see which hotspot gives best communication, which hotspots are not well covered. That allows us to know at what area we maybe will not be able to reach or where reach will be worse.
We did testing with 6 different antennas from 1 location. We can conclude that best antenna is Type 4 5.5dBi antenna, 80cm long, because it has the best signal quality and can reach the most hotspots. Antennas Type 3 and Type 5 are almost the same compared one to other.
Question is do we really need this biggest Type 4 antenna or can we go with smaller antennas Type 3 and Type 5?
In our case, we can go with smaller antennas. For our case, at 7th floor of building, we can reach to enough (100+) hotspots with smaller antennas. There are pros and cons for bigger and smaller antennas.
But we will talk about that in our next blogs, about how to choose antenna for specific location. 🙂
Let us know how you like our tools and feel free to leave us feedback on email.