Help. Poor coverage


#1

Hello,
I'm trying to set up a gateway at my University to cover the entire campus (max 1,5km). This will be located on a mast located on the roof of a building (approximately 20 meters).

My gateway (868MHz) is a ic880A-RasPi combo with a gp901c antenna (https://webshop.ideetron.nl/GP901C). For the software I use the Zurich TTN library (https://github.com/ttn-zh/ic880a-gateway/wiki).

My Node is an Arduino Nano with an RN2483 chip and an indoor antenna

Before installing the antenna in its final site I am doing tests with it in my house (I live on an eighth floor, 25m high).

The test installation consists of fixing the antenna in the window of my house, in front there is no building of more than 3 floors.

Compared to data from other projects (where they even talk about 10km ranges) my results are frustrating. I can only connect when I am at 100m from my house and without any obstacles.

In a previous experiment we managed to reach 180 meters (with a whole street of buildings in the middle) putting the gateway in a room with an indoor antenna.

Since I'm a rookie in telecommunications, I'm a bit lost.

I would like to know what I am doing wrong or what information I can contribute to know where I am failing.

I do not know if I should increase the output power of the gateway (gain), if the test facility without a mast is determinant ... or what.

Thank you in advance.


(Vseta) #2

The smaller size of data packets and higher Spread Factor with higher gain the longer the range. Manual antenna impedance matching is usually performed to make sure of efficient connection.

Some windows have heat shield that attenuates signal, hence lower range.

Here is an article on Antenna fundamentals: https://www.digikey.ca/en/articles/techzone/2011/mar/understanding-antenna-specifications-and-operation

Edited to better reflect other user's experience with this particular antenna.


#3

This antenna works fine and we got measurements of >20 km with it.

It sounds like you have highly isolated glass. But still I think the 180 meters aren't great either. Are you sure your node works as it should?


#4

Hello, thanks for answering.
I forgot to update the post.
Finally I solved it, the problem is that I was using the wrong UFL of the ic880a.
I have searched the datasheet which is the difference but I still don't know very well.