I use a Raspberry Pi 3 to send USB data from an RTL_SDR via rtl_tcp over the network to my iPhone.
If your rtl_tcp server (Raspberry Pi 3, Zero W, et.al.) can't be wired to your ethernet router, and is some distance from your WiFi access point, you could try WiFi with two directional WiFi antenna's (high gain Yagis, etc.) pointed at each other.
rtl_tcp using lower sample rates (240k) sometimes works better over slower WiFi links.
Main forum to discuss RTL-SDR related topics.