Arachna Networks proposes to strengthen urban communication networks to function effectively under both ideal and adverse conditions by leveraging open-source software and commercial off-the-shelf hardware including software-defined radios (SDRs) to build resilient mesh networks. Arachna Networks builds upon lessons from the development of our RTAK technology (i.e., end user devices (EUDs) that integrate the Reticulum network stack (RNS) and ATAK) --which was a semifinalist for the CivX TAK/ATAK for Smart Cities Challenge-- to improve existing urban radio access networks (RANs) and provide uninterrupted connectivity for smart infrastructure (such as IP cameras, drones) in congested and/or contested spectrum environments. We have expanded the capabilities of RNS with smart spectrum sensing functions and tested them with multi-radio platforms (such as 915 MHz LoRa radio chipsets and sub-6 GHz SDRs) to demonstrate resilient connectivity in the presence of jamming, spoofing or denial-of-service attacks in urban network infrastructure. Our technology is designed to be cost-effective, scalable, and easy to integrate into existing urban radio access network systems. Our goal is to create a software-defined kit that would be plug-and-play with existing urban radio-access network (RAN) platforms and augments their zero-touch mesh networking functions to enhance their self-healing capabilities and facilitate operational resilience.