In the UK you're allowed to radiate -6dBm in this band.
I've obtained a 50m range with -6dBm Tx power , and a simple superregen receiver, sensitivity -97dBm
in open air using loaded 1/4 wave whip antennas about 8cm long. The data rate was 1200 baud, and used ( obviously) simple on/off modulation
A dipole would give about 1.6dB more - not very much.
Obviously if there are obstacles or bad reflections this would make things worse.
If you're allowed more power where you live you'd get better range. And a better receiver would improve things too.
regards
Allan