Build a solar repeater for your neighborhood

What you are building: a radio that sits up high, runs on sunlight, and passes messages between radios that cannot hear each other. One good repeater often does more for a neighborhood mesh than every handheld upgrade combined.

Research-based, from the Meshtastic, MeshCore and maker documentation. We have not built and monitored one of these through a winter yet, and we will not quote runtime or range until we have.

Step 1: Find the site, and permission

Height and a clear view matter most. A roof peak, a tall pole, a friend’s barn, a hill. Check the clear zone with the line-of-sight calculator toward where your radios will be.

Get permission in writing if it is not your property. Check HOA, lease and landlord rules. Plan for someone to reach it for maintenance.

Step 2: Ready-made or DIY

Ready-made: the SenseCAP Solar Node P1 combines a 5 W panel and four 18650 slots. The base P1 ships without cells; the P1-Pro includes them and adds GPS. It is documented for Meshtastic, and a MeshCore repeater variant is sold by at least one retailer.

DIY: a low-power board such as the Heltec Mesh Node T114, which Heltec lists at around 11 microamps in deep sleep, in a sealed box with a cell and a small panel. More work, more choice of antenna and battery, and you own every failure point.

Step 3: Flash and set the role

Meshtastic uses one firmware with a role setting. Its docs describe:

• Router: rebroadcasts once; “best positioned in strategic locations to maximize the network’s overall coverage.”
• Router Late: rebroadcasts after other nodes; suited to dead spots and local clusters.
• Repeater: rebroadcasts with minimal overhead and does not appear in the node list.

On ESP32 boards, the docs note, Router turns on power saving automatically. If you are joining an existing mesh, ask its organizers which role they want; too many routers in one area can make things worse.

MeshCore uses separate repeater firmware from its web flasher. Its FAQ notes:

• The repeater does not forward every packet it receives.
• Configuration is over USB serial through its config site or the flasher console.
• The default admin password is “password”. Change it before the node goes up.
• Repeaters send a flood advert every 12 hours by default.

Set the US region and the same radio settings your mesh uses, exactly as for a handheld. See your first hour.

Step 4: Size the battery and panel

Do not trust anyone’s battery-life number, including a forum post, for your node, role and climate. Instead:

1. Run the node at home for 24 hours with a USB power meter logging its average draw.
2. Enter that draw, your cell capacity and your worst month’s sun hours into the node battery calculator.
3. Aim for a battery that rides through several sunless days, and a panel that refills it in the sun you actually get.

The calculator’s efficiency default is a planning assumption, not a measurement. Lower it for any shade.

Step 5: Antenna and cable

• On a roof with radios close below, a lower-gain antenna keeps signal pointed down. On a tall open mast, a mid-gain omni pushes it toward the horizon. Antennas, height and coax explains the trade.
• Stay at or under 6 dBi unless you reduce power, per 47 CFR 15.247(b)(4).
• Keep coax short. At 900 MHz, LMR-400 loses 3.9 dB per 100 ft per Times Microwave. Better still, mount the node at the antenna.

Step 6: Mount it safely

• Roof and mast work carries fall and power-line risks. Do not work alone, and stay well clear of power lines.
• National Electrical Code Article 810 covers outdoor antenna masts: a listed discharge unit on each lead-in, the mast grounded, a copper grounding conductor of at least 10 AWG, and never the electric service mast as a support, per an EC&M summary. Check your local code edition; an electrician can do the grounding.
• A weatherproof box is not lightning protection.

Step 7: Secure it

• Do not load your private channel onto an unattended repeater. Meshtastic’s encryption docs warn that physical access can expose the key. A repeater forwards packets it cannot read.
• Change any default admin password.
• Note the firmware version and settings somewhere safe.

Step 8: Check it from the ground, then on a schedule

• Confirm messages pass through it from radios that could not reach each other before.
• Check it monthly at first, then seasonally. Winter is the test for solar.
• Keep firmware in step with the rest of your mesh.