What is the right antenna type I can use for the Limesdr device? Does anyone knows ? 2.5 dbi antenna I looked but it is so weak . I found 15 dbm wireless powerful antenna but I am undecided.
What frequencies do you want to use? Antennas are meant for certain parts of the spectrum.
I want 900 1800 Mhz osmocom frequencies .
You mean GSM900 and DCS1800 bands? There are plenty of antennas for those and you just need to search online. Note that the much higher gain ones will be highly directional and so whether they would be suitable depends on your use case.