Thoughts on this Antenna

despite reading lots or posts I am really not getting Antennas
I’m not really a hardware guy.

I am looking to improve the range over stock antennas that came with the t-beams
all I am confident on is that they should be 868mHz

am I in the right ball-park ?

Antennas are black magic and it always depends on what you want to do. I use similar omnidirectional antennas for my fixed stations & repeaters and the work incredibly well for connecting to nodes all around. If you have a specific node that you want to reach, you can use a directional antenna like the Zipp 9.

That’s a fairly reasonable dipole antenna. Be aware that as it is designed to give gain, it will give a stronger signal perpendicular to the antenna rather than out of the end of it, so it helps if you can keep the antenna pointed upright.

I bought this very similar dipole antenna:
https://uk.rs-online.com/web/p/telemetry-antennas/2025828/

For the moment the plan is to have a static unit with the best possible omnidirectional antenna placed as high as I can get it while still being able to get to it without climbing a ladder.
As it stands I can only mount it on the outside wall of an upstairs window, should there be an affordable antenna that can be mounted higher without the t-beam being out of reach then I would go for that.

My thinking is , that the ‘hub’ as the home unit , where power supply is plentiful and where the size and choice of antenna isn’t limited (because it doesn’t need to be transported) should be as good as I can make it. The mobile units would of course be less so if the antenna was cumbersome.

An option for a fixed home station would be a designated LoRa antenna like this:
https://www.delock.de/produkt/12504/merkmale.html

Be aware to select the correct RF cable to keep signal loss as low as possible.