Need help with selecting stronger Antenna

Right now for my IOT project I use an antenna that has a gain of about -2.2dBi. It can connect to the cellular network fine, but this often takes a long time and can easily total to several minutes.

However, looking at the talk about antennas leaves me very confused regarding what would be best to have for my project. I want to deploy my sensor device out in the environment, but won't have control over the positioning of the antenna (hence directional antennas wouldn't work well). Cost of the antenna isn't too important.

Considering it needs to connect to 850/1900MHz cellular bands and needs to be reliable regardless of positioning, what kind of dBi gain should I aim for to achieve a substantial improvement over my current -2.2dBi antenna?

Not possible given your constraints of cant be directional and no control of the antenna positioning.

Vitesze:
Right now for my IOT project I use an antenna that has a gain of about -2.2dBi.

Suspect you mean, +2.2dBi ?

It can connect to the cellular network fine, but this often takes a long time and can easily total to several minutes.

And how have you verified that this is due to weak signals ?

srnet:
Suspect you mean, +2.2dBi ?

And how have you verified that this is due to weak signals ?

The store page specifically mentions -2.2dBi, but perhaps you're right.

I used some code to map the cellular strength of the devices, and in a few cases it returns a pretty low value (it maps from 1 to 5, and I get 1s and 2s at times, while at my own desk I consistently get 4s and 5s)

Look for an omnidirectional antenna with positive dBi. The basic element is usually several multiples of 1/4 wave and so has a flatter radiation profile in the vertical direction.

Vitesze:
The store page specifically mentions -2.2dBi, but perhaps you're right.

I used some code to map the cellular strength of the devices, and in a few cases it returns a pretty low value (it maps from 1 to 5, and I get 1s and 2s at times, while at my own desk I consistently get 4s and 5s)

Cant see how that tells you that the longer connect time is as a result of weaker signals.

Moving the sensors nearer to the cell tower would be one way of checking.

srnet:
Cant see how that tells you that the longer connect time is as a result of weaker signals.

Moving the sensors nearer to the cell tower would be one way of checking.

What other reasons are there for a longer connect time? Genuinly wondering as my devices work great but can't connect about 20% of the time.

jremington:
Look for an omnidirectional antenna with positive dBi. The basic element is usually several multiples of 1/4 wave and so has a flatter radiation profile in the vertical direction.

So something like this for instance? Buy Manufactory 900 1800MHz Hotselling Magnetic in China on Alibaba.com

So something like this for instance? Buy Manufactory 900 1800MHz Hotselling Magnetic in China on Alibaba.com

You are joking, of course.

Search for "high gain omnidirectional cellular antennas" and expect to spend $50-$100 for one that actually works.

jremington:
You are joking, of course.

Search for "high gain omnidirectional cellular antennas" and expect to spend $50-$100 for one that actually works.

Should have mentioned, but size is an issue in my project. Up to about 100mm is fine, but all of these high gain antenna are far too big (some are over 50cm) to incorporate in my project.

To be fair though, the one I linked claims to have 5dbi, whereas my current one apparantly is 2.2dbi only.

I would not believe an Alibaba claim of 5dBi for a $2 antenna, but that is not much money to waste. You can always throw the antenna away if it doesn't work. See below.

Earlier, you quoted -2.2dBi for the antenna you have. What is it?

Adjust antenna for best reception:

jremington:
I would not believe an Alibaba claim of 5dBi for a $2 antenna, but that is not much money to waste. You can always throw the antenna away if it doesn't work. See below.

Earlier, you quoted -2.2dBi for the antenna you have. What is it?

Adjust antenna for best reception:

It is -2.2dbi, at least according to the store page. I found this one from Taoglas:

Which probably would fit in my sensor enclosure (though narrowly) and has a 5dbi gain for 1900MHz. And the company that produces them, Taoglas, seems to produce reliable and good-quality antennas. I ordered one, just to see if it will improve my connectivity a bit.