Not built yet. This is my plan and parts list. When it's done I'll add what I actually heard and anything I'd change.
What to expect
A crystal set has no amplifier. Every bit of sound you hear comes from the energy the aerial catches. So be realistic about what that means.
- Medium wave will be clear. Local and national MW stations come in well, especially after dark.
- Shortwave will be quiet and it will fade. You'll hear the big international broadcasters, mostly in the evening, through an earpiece. Signals drift in and out. That's normal for shortwave, not a fault.
- No loudspeaker. There isn't enough power to move a speaker cone. You listen on an earpiece or headphones.
- The aerial decides everything. A long wire up high is the difference between hearing stations and hearing nothing. A telescopic rod won't do it on shortwave.
Why this design
I started from a classic design, the EconOceanic (credit at the bottom). It works, but it uses four separate switches and a battery-powered speaker. I've kept what makes it good and cut what makes it hard to use.
A crystal set is the only receiver that runs on zero power. Add a single transistor and you need a battery. So the whole design is about wasting as little signal as possible.
With no amplifier, signal strength comes from wire length and height. That's why the biggest single spend is 50 m of copper wire and a proper earth rod.
Each coil has its own small aerial winding. A two-pole switch picks both windings at once. The original needed two switches to change band, and mixing them up is where people get lost.
A toggle switches the tuning capacitor between wide (find a band) and fine (separate the stations in it). Shortwave stations sit close together, so fine tuning makes them usable.
A long wire on shortwave can swamp the tuning and you hear several stations at once. The second input goes through a small adjustable capacitor, so you can trade a bit of volume for sharper tuning.
Cardboard soaks up damp and changes shape, which shifts the tuning. PVC doesn't. The 40 mm tube is almost the same size as the old paper-towel tube the original used.
How it works
Four stages. Each one is a part you'll hold in your hand.
Catch
The aerial wire picks up every station at once as tiny currents. The earth connection gives those currents somewhere to flow.
Choose
A coil and the tuning capacitor form a tuned circuit. It rings at one frequency and ignores the rest. The band switch picks the coil, the tuning knob picks the frequency inside that band.
Detect
The germanium diode strips the radio wave away and leaves the audio. It's the "crystal" in crystal set. Germanium is used because it starts conducting at a very low voltage, so weak stations still get through.
Hear
A crystal earpiece turns that tiny audio signal into sound. It needs almost no power, which is why it works when normal headphones won't.
Parts list
Everything below is on Amazon UK, checked 7 November 2026. Listings change, so check each one before you order. Budget about £230 for the lot, of which about £60 is the aerial and earth.
These are affiliate links. If you buy through them I make a small commission, at no extra cost to you. It helps cover the cost of running this site. This is a hobby, not a shop.
The radio
Listening
Aerial + earth
Small extras
Tools you'll also need: soldering iron, drill + bits (3, 6.5, 7, 9.5 mm), small hacksaw, fine sandpaper, multimeter, masking tape, marker.
Build it
Nine steps. Do them in order. The coils are the slow part. Everything else is a couple of evenings.
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Check every part first
Open everything and lay it out. Find the diode, a 1nF capacitor (marked
102), a 100k resistor (brown-black-yellow on a 5% resistor, brown-black-black-orange on a 1%), and a 40pF trimmer.Put the multimeter on the tuning capacitor. Find the two big sections. If your meter reads capacitance, each one shows about 266pF with the plates fully closed. Mark them A and B with tape. The common pin goes to earth.
Why: halfway through a build is the worst time to find a part missing or not knowing which pin is which.
-
Drill the lid
Everything mounts on the lid, so you can lift the whole radio out. From the left: TUNE (the capacitor, 7 mm hole plus two 3 mm screw holes), RANGE toggle (6.5 mm), BAND switch (9.5 mm). Drill a 3 mm hole near the middle for adjusting the trimmer with a small screwdriver.
On the left end of the box: three spring terminals for ANT 1, ANT 2 and EARTH. On the right end: the EAR socket (6 mm hole).
Hold the real knobs on the lid before you drill to check they don't clash. Wear glasses: plastic chips fly.
Fig 2 · Lid layout. Hole sizes are for the parts listed. Check yours with calipers or a ruler first. Why: big tuning knob on the left, band on the right, so your right hand rests on tuning, the knob you touch most. Terminals go on the ends, so aerial wires don't trail across the controls.
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Make the coil tube
Cut 120 mm off the PVC tube with a hacksaw and sand the ends square. Draw a straight line along its length with a marker. That's your start line: every winding starts and stops on it, so turn counts are easy to keep.
Drill pairs of 1 mm holes where each winding starts and ends (positions in the table below). Thread the wire end through the hole and back out to anchor it. Leave 25 cm tails.
Why: a wire anchored through the tube can't unwind while you work. The old method of gluing as you go is messy and easy to get wrong.
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Wind the four coils
Each band has two windings: a small aerial winding and a bigger tuning winding, 3 mm apart. Wind both in the same direction, turns tight and touching. Label every tail with masking tape as you go, for example
2-AER-START.Coil Wire Aerial winding Gap Tuning winding Inductance Starts at 1 · MW 0.4 mm 14 turns 3 mm 70 turns ≈160 µH 5 mm 2 · SW low 0.6 mm 5 turns 3 mm 20 turns ≈20 µH 55 mm 3 · SW mid 0.6 mm 3 turns 3 mm 10 turns ≈6 µH 84 mm 4 · SW high 0.6 mm 2 turns 3 mm 6 turns ≈2.5 µH 105 mm Fig 3 · Coil tube to scale. Pale blocks are aerial windings, solid blocks are tuning windings. About 10 mm between bands. When all four are done, brush on two thin coats of varnish. Let it dry overnight.
Why: the turn counts set the bands. I worked them out for a 40 mm former and this capacitor, so each band overlaps the next and there are no gaps. The aerial winding is about a fifth of the tuning winding. That's enough to pass the signal across without the aerial dragging the tuning around. The 10 mm gaps stop neighbouring coils from interfering with each other.
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Mount the coil and the parts
Stick two rubber feet on the underside of the tube and glue them to the inside of the lid with Araldite. Keep the coil at least 15 mm from the tuning capacitor. Fit the capacitor, toggle and band switch through their holes and tighten the nuts. Fit the terminals and the EAR socket in the box ends.
Why: the feet lift the coil so wires can run underneath. The gap to the capacitor stops the coil picking up its metal and shifting the tuning.
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Make the earth bus
Run one bare piece of 0.6 mm wire along the inside of the lid, from the EARTH terminal to the far end. Every connection marked "earth" in Fig 1 joins this one wire: the ends of all eight windings, the capacitor common pin, C2, R1 and the socket's sleeve.
Why: one earth wire is easier to check than lots of separate earth joints, and it keeps the signal path short.
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Wire the band switch
Find the switch's two poles with the multimeter. Each pole has a centre tag (common) and six outer tags. Turn the shaft to position 1 and see which outer tag connects to each common. Do the same for positions 2, 3 and 4.
- Pole A common → ANT 1 terminal. Also → ANT 2 terminal through the 40pF trimmer.
- Pole A, positions 1–4 → start of aerial winding on coils 1–4.
- Pole B, positions 1–4 → start of tuning winding on coils 1–4.
- Pole B common → tuning capacitor section A.
- The finish of every winding → earth bus.
Scrape the enamel off every wire end with fine sandpaper until the copper is bright, all the way round. Check each coil with the multimeter through the switch before you solder.
Why: enamel left on a joint is the most common reason a crystal set stays silent. The joint looks soldered but nothing passes through. Testing before soldering means a mistake costs seconds, not desoldering.
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Wire tuning, detector and earpiece
- Capacitor section A → pole B common. That's the tuning node.
- Capacitor section B → one side of the RANGE toggle. Other side of the toggle → tuning node. Toggle on = WIDE, off = FINE.
- Diode from the tuning node to the EAR socket tip. Leave its legs long and hold it in with crocodile clips for now.
- C2 1nF and R1 100k both from the socket tip to the earth bus. Socket sleeve to the earth bus.
- Leave the two small 20pF sections on the capacitor unconnected.
Why: leaving the diode on clips lets you try the germanium and the Schottky on a real station and solder in the louder one.
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Put up the aerial and earth
Run 20–40 m of wire as high and as straight as you can: house to a tree, or to a pole at the end of the garden. Put an insulator at each end and tie the support rope to the insulator, not to the wire. Bring the end to the window and into ANT 1.
Drive the earth rod into damp ground, as close to the radio as you can. Clamp a wire to it and run it short and straight to EARTH. Don't coil up the spare.
Why: this is the step that makes the radio work. Height gets the wire above buildings and noise. Length catches more signal. The earth completes the circuit. A shoddy aerial will make the best-built set sound dead.
First listen
Start on medium wave
Band 1, RANGE on WIDE, aerial in ANT 1, earpiece in. Wait until dark and turn TUNE slowly. You should hear UK medium wave stations.
Why: MW is strong and always there. If it works, the radio is built right. If you hear nothing on MW, the fault is the wiring, not shortwave conditions.
Pick the best diode
Park on a weak station. Swap between the germanium and the Schottky diode. Solder in the louder one.
Move to shortwave in the evening
Band 3, WIDE. Sweep slowly. When you catch something, flip to FINE and retune to separate it from its neighbours.
Too many stations at once?
Move the aerial to ANT 2 and turn the trimmer down with a small screwdriver. You'll lose some volume and gain separation. Find the setting where it's just clear.
Keep a log
Write the time, band, range, rough knob position and what you heard. After a week you'll know where everything sits.
| Band | WIDE covers | FINE covers | Good for |
|---|---|---|---|
| 1 · MW | 0.53–2.0 MHz | 0.74–2.3 MHz | UK medium wave, any time; distant MW at night |
| 2 · SW low | 1.5–5.6 MHz | 2.1–6.5 MHz | 90 m, 75 m, 60 m bands, night |
| 3 · SW mid | 2.8–10.3 MHz | 3.8–11.9 MHz | 49 m, 41 m, 31 m: the busiest broadcast bands, evening |
| 4 · SW high | 4.3–15.9 MHz | 5.9–18.4 MHz | 25 m, 22 m, 19 m, 16 m bands, daytime |
These are calculated figures. Wiring and tolerances move them, so expect yours to be 10–20% off. Rule of thumb: lower frequencies work better at night, higher ones in daylight. For what's on air right now, check a live schedule such as short-wave.info.
A crystal set only decodes ordinary AM. Amateur voice (SSB) sounds like garbled ducks, and Morse comes through as thumps. That's a limit of the design, not a fault.
If it's quiet
| What you hear | Most likely cause | Fix |
|---|---|---|
| Nothing on any band | Enamel on a joint, or a bad earth | Re-scrape and resolder the coil tails. Check EARTH. Touch the aerial wire: you should hear a click. |
| Fades to silence after a few seconds | No 100k across the earpiece | Fit R1. The earpiece needs it to let the diode reset. |
| MW fine, shortwave dead | Wrong time of day or band | Try band 3 after dark. Check a live schedule. Make sure the small SW coil tails are soldered. |
| Two or three stations at once | Aerial too tightly coupled | Use ANT 2, turn the trimmer down, switch to FINE. |
| Loud hum | Aerial near mains wiring | Move the wire away from the house. Improve the earth. |
| Very quiet everywhere | Aerial too short or too low | More height first, then more length. Try the other diode. |
Safety
- Lightning. Unclip the aerial and lay the end outside whenever a storm is anywhere near. Never listen during thunder.
- Power lines. Keep the aerial well clear of overhead power and phone lines, including if it falls.
- Earth rod. Check for buried cables and pipes before you drive it in.
- Never use a gas pipe or the mains earth as your radio earth.
Notes + credits
This build is based on the EconOceanic crystal shortwave radio designed by Walter Heskes and published on Phil's Old Radios. It's well worth reading. My changes: one two-pole band switch instead of separate coil and capacitor switches, coils recalculated for a 40 mm PVC former and the capacitor I could buy in the UK, a wide/fine range toggle, a series trimmer on a second aerial input, and no battery-powered speaker.
Coil values come from the standard single-layer coil formula (Wheeler) and the tuning ranges from f = 1 ÷ (2π√LC), allowing about 30–40pF of stray capacitance. They haven't been tested on a built set yet. I'll update this page with real numbers when mine is done.