An antenna is tuned for a frequency range. A 433 MHz antenna on an 868 MHz board (or the other way round) reflects most of the transmitter's power back into it: range collapses, and at 22 dBm the radio can be damaged. Check the band printed on the antenna, and never transmit with no antenna connected.

Cheap boards often ship with a generic stub that is not tuned for either band. Replacing it is the single best upgrade.

Stub or “rubber duck”

Gain: 0 to 2 dBi

Good for: Handhelds and testing on a desk

Quarter-wave whip (433: about 16.5 cm; 868: about 8.2 cm)

Gain: about 2 dBi

Good for: Cheap, easy, works well with a ground plane (a metal box lid or a few radials)

Half-wave dipole

Gain: about 2 dBi

Good for: Needs no ground plane; a good indoor or window antenna

Collinear or fibreglass omni

Gain: 3 to 6 dBi

Good for: The usual choice for a fixed node on a mast; flat coverage all round

Yagi or panel

Gain: 6 to 12 dBi

Good for: Point-to-point links to one distant node; narrow beam, must be aimed

Gain is not free. A high-gain omni squashes its coverage into a flat disc: on a hilltop node it can fire over the heads of everyone in the glen below. For a node looking down on its users, 3 dBi or a slight downward tilt is often better than 6.

At these frequencies range is mostly about what is in the way. LoRa will go many kilometres with a clear line of sight and struggle to cross a village with none.

• Height beats power. Doubling transmit power adds a few hundred metres in the open; getting the antenna above the rooftops multiplies range.

• Trees matter more than people expect, and wet trees more than dry ones. Coverage measured in August is not coverage in January.

• Hills are walls, but they are also the best sites: a node on a hill sees everything on both sides of it.

• Indoors is lossy. A window facing the direction you care about is far better than the middle of the house. Foil-backed insulation and metal-framed windows block almost everything.

Free tools such as HeyWhatsThat (heywhatsthat.com) and radio coverage planners will draw the horizon from a point; use them before buying a mast.

Coaxial cable loses signal, more at 868 MHz than at 433, and thin cable loses most. Ten metres of RG174 at 868 MHz throws away roughly half the power; ten metres of LMR-400 loses almost nothing. Keep the run short, use decent cable (LMR-240 or better for anything over a few metres), and put the radio near the antenna if you can: a standalone node in a box at the top of the pole with a short tail to the antenna beats a long feeder to a radio indoors.

Connectors: most boards have a u.FL or IPEX socket; most antennas have an SMA plug. Check whether you need SMA or RP-SMA (reverse polarity; common on Wi-Fi kit); they look alike and do not mate. Every adapter is a small loss and a place for water to get in.

Scotland's weather gets into everything. Seal connectors with self-amalgamating tape, make sure cable enters a box from below with a drip loop, use a fibreglass antenna outdoors rather than a bare whip, and expect to check it after the first winter.

A relay that has to survive a Scottish winter on a panel needs more panel and battery than a summer test suggests: December gives perhaps a tenth of June's energy, and a fortnight of cloud is normal. Face the panel south and tilt it steeply (60° or more) for winter. The ScotMesh firmware can lower transmit power or switch the radio off below a battery level you choose, which turns a dead node into a quiet one that comes back with the sun.

• The licence-free bands limit both transmit power and how much of the time you may transmit. The ScotMesh profiles are within those limits; adding a high-gain antenna raises your effective radiated power, so do not pair the 22 dBm profile with a high-gain directional antenna without checking the rules for the band.

• Transmit power is the least effective knob. If a link is marginal, raise the antenna, shorten the cable or move the node before raising the power.

Real results from real sites in Scotland are worth more than any of the above. When you measure a link, note the two sites, antennas, heights and the RSSI and SNR reported by rnstatus or the node's page, and put them on the ScotMesh Discord (discord.gg/ytxfyuDmSt) or add them here.