HERMES (High-frequency Emergency and Rural Multimedia Exchange System) offers affordable digital telecommunications over the High Frequency (HF) band, accessible through a simplified visual interface on smartphones or computers. It enables the transmission and reception of various data types, including email, text, audio, documents, photos, and GPS coordinates. To ensure security, senders can easily encrypt and password-protect transmitted information. HERMES, encompassing both architecture designs and software, is free and open-source.

Originating in the Amazon rainforest to address telecom access challenges, HERMES utilizes HF as a last resort due to its wide coverage capabilities via ionosphere skywave propagation. Starting in 2015 with off-the-shelf hardware and Raspberry Pi 2 or 3, HERMESv1 (2018-2020) evolved to custom hardware, relying on Airdrop or VARA modem and UCCP for transfer, consuming about 15 watts of power. HERMESv1.x was deployed in the Amazon region from 2019 to 2023.

In 2023, HERMESv2 was introduced as an open-source wideband HF transceiver, featuring the sBitx radio, reduced size, and native voice support (mic+ptt+speaker). HERMES’s Web interface offers a WiFi landing page with email, news, a BBS-inspired message board, and configuration screens. Images are compressed to 10KB or less using the h.266 image encoder before transmission, while audio encoding utilizes lpcnet compression. Delta Chat is recommended for email communication, bundled with Roundcube (Postfix + Dovecot). Currently, 10 KBps can be transferred to a gateway under favorable signal conditions.

The radio costs $500 without batteries, serving both as the gateway and endpoint. HERMES utilizes P2P connections and multicast for transmission. Future developments include support for real-time messaging, DRM broadcast, and digital telephony.

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