Radio Experiments with EcoGather

Winter 2025 Seminar Topics #

We're planning a series of short, informal presentations and discussions around topics of interest to the group. Below is a rough, to-be-refined categorization of technologies that seem to be of interest:

Listening-only (short and long range, no license required) #

In general, it is often useful in a grid-down scenario to be able to listen into ambient broadcasts (news, fire, police, emergency services). There are various inexpensive approaches to this, including:

• Scanners -- small radios that can receive local police, fire, and other broadcasts
• Software-defined radios -- inexpensive dongles that, when connected to a laptop, can provide an intuitive graphical way of exploring received radio signals
• Short-wave radios -- radios optimized for receiving broadcasts from around the globe

Short-range transceivers (several miles), no ham license #

These are relatively inexpensive radio technologies that allow for off-grid communication within a range of a few miles (or tens of miles, with repeater nodes). This would be useful for folks on a homestead, or perhpas within a relatively small town, to stay in touch.

• Meshtastic (enables phone to do off-grid, mesh-networked texting via an inexpensive add-on module; unlicensed)
• GMRS (audio communication; a $35, no-exam license is required)
• Walkie Talkies (audio communication; no license required)

Medium-range transceivers (100s of miles), ham license req'd #

For off-grid coordination of logistics (food, water, transport) -- e.g. after or during a storm, flood, or fire -- it seems often to be useful to communicate within a range of a few hundred miles. A typical approach to this is to a technique (NVIS) that bounces radio signals off the atmosphere nearly directly above the broadcasting site, so that signals land within the desired range. The relevant bands (typically, HF), require a ham license (typically, the higher-level, 'General' license). Example technologies include:

• js8call; varac -- keyboard-to-keyboard live chat, with store-and-forward capability
• winlink -- ham radio-based email program