I have built several remote controls with IFM electronic's bluetooth receiver(BT 2.1+EDR)with antenna to read truck weight data. Many of them work very well and have an operating distance of up to 90m. However, there are devices that work very badly and the distance is only about less than 20m. In each device I use the MIT app that I made and the same receiver. So, the problem is Bluetooth disconnection several times within a short period of time.
Do you have any experience with differences in operating range between different mobile phone brands?