Size a solar system with arithmetic instead of guesswork, wire it without a fire, and learn the whisper that crosses a thousand miles on watts. The reference tables print; the trainer is a game.
☀️ The solar sizer
Rules baked in: ~30% real-world losses (charging, wiring, dirt, heat); batteries sized to their safe depth of discharge; controller sized at 125% of panel current. Watt-hours = each device's watts × its hours. A fridge lies — measure it across a full day if you can.
Respect the order of connection: battery to controller FIRST, panels last (and reverse to disconnect). Fuse every wire that leaves a battery, as close to the post as possible. A battery bank stores a fire's worth of energy — treat it like one.
🔌 12-volt wiring that doesn't burn
load at 12 V
up to 3 m run
up to 6 m run
fuse it at
5 A (lights, radio)
16 AWG / 1.5 mm²
14 AWG / 2.5 mm²
7.5 A
10 A (laptop, pump)
14 AWG / 2.5 mm²
12 AWG / 4 mm²
15 A
20 A (fridge, inverter-small)
10 AWG / 6 mm²
8 AWG / 10 mm²
25 A
40 A (big inverter)
8 AWG / 10 mm²
6 AWG / 16 mm²
50 A
Low voltage forgives shocks, not shorts: 12 V will weld a wrench across battery posts. Remove rings; insulate tools.
The run length is BOTH ways (out and back). When between sizes, go thicker — copper is cheaper than a fire.
Fuse ≈ 125% of the steady load, always smaller than what the wire can carry. The fuse protects the WIRE, not the device.
Never mix old and new batteries, or different chemistries, in one bank. Series adds volts; parallel adds amp-hours; matched batteries only, either way.
📻 The ham shelf — being heard beyond the horizon
Listening is free, everywhere, always — any shortwave/SDR receiver, no license. Transmitting needs a license in normal times (the exams are genuinely easy, and hams welcome newcomers). In a true life-and-death emergency, any station may use any means to call for help — that exception is real law nearly everywhere, and only for that.
Where the voices are: 80 m — regional, at night · 40 m — the all-day workhorse, a few hundred km · 20 m — daytime, across oceans · 2 m/70 cm FM — local line-of-sight, the handheld bands; repeaters extend them across a region.
The wire that works: a dipole. Two equal wires fed in the middle, as high as you can hang them. Length is pure arithmetic → the calculator belowtotal metres = 142.6 ÷ MHz.
Protocol for being heard: listen first, twice as long as feels natural. Speak plainly. Give the callsign slowly, in phonetics. Short transmissions, real pauses. "CQ CQ CQ, this is …" calls anyone; answer with both callsigns.
phonetic alphabet (say it so static can't bend it)
A Alfa
B Bravo
C Charlie
D Delta
E Echo
F Foxtrot
G Golf
H Hotel
I India
J Juliett
K Kilo
L Lima
M Mike
N November
O Oscar
P Papa
Q Quebec
R Romeo
S Sierra
T Tango
U Uniform
V Victor
W Whiskey
X X-ray
Y Yankee
Z Zulu
numbers said digit by digit — "one four five"
🎵 The Morse trainer — a game with a real prize
Two ways to play. The table itself is on the one-pager shelf — print it; train here.
👂 Copying — hear it, type it
🔑 Keying — send it yourself
short press = · long press = —
Part of the Ark. Original prose; standard electrical practice and the universal radio conventions — provenance in DATA-SOURCES. Corrections: 🔔 ring the bell.