If you've already increased the transmit power with NRF.setTxPower then yes, I guess you're going to have to look at ways to make the receiver better.
As a very low-tech solution you could make the receiver more directional by placing it in the middle of a parabolic reflector - you could google 'Cantenna' for some super cheap options.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
If you've already increased the transmit power with
NRF.setTxPower
then yes, I guess you're going to have to look at ways to make the receiver better.As a very low-tech solution you could make the receiver more directional by placing it in the middle of a parabolic reflector - you could google 'Cantenna' for some super cheap options.
Just using an external USB Bluetooth dongle might help, especially if you found a good one, or one that you could attach an external aerial to. No promises, but at least something like https://www.newfrog.com/p/150mbps-wifi-bluetooth-4-0-wireless-usb-adapter-network-card-with-antenna-125900.html seems to have a better aerial on it.
Otherwise if you're just on a phone you might be a bit stuck I'm afraid.