Your First Open Energy Experiment for Under $50

The meta-pattern post laid out the thesis: 768 patents, three recurring principles, 29 experiments. But a thesis is just words until someone builds something.

This post is about building something. Specifically, it's about running the most accessible experiment in the Open Energy catalog — the Bifilar Coil Resonance Characterization — with components you can order today and have on your bench by the weekend.

Total cost: under $50. Time to first measurement: about two hours. No prior experience required beyond basic soldering.

What you're measuring and why

A bifilar coil is a coil wound with two parallel wires instead of one. It's been a curiosity in electrical engineering since Nikola Tesla patented his bifilar coil design in 1894 (US Patent 512,340). The interesting property: depending on how you connect the two windings, a bifilar coil can have a dramatically different self-resonant frequency than a conventional single-wire coil of the same dimensions.

Self-resonance is important because it's where the coil stops behaving like a simple inductor and starts behaving like a resonant circuit — an LC tank where the coil's own parasitic capacitance tunes against its inductance. At self-resonance, energy sloshes back and forth between the magnetic field (inductance) and the electric field (capacitance) with minimal loss.

That's one of the three meta-pattern elements: resonance. And the bifilar geometry — with its unusual inter-winding capacitance — is a form of non-linearity in the circuit's impedance response.

By measuring the self-resonant frequency, impedance magnitude, and Q factor of both a conventional and a bifilar coil on the same core, you produce a direct comparison of how winding geometry affects the resonant behavior of a simple system. That's real data. That's what the platform needs.

What you need

The instrument: NanoVNA (~$30)

A NanoVNA is a pocket-sized vector network analyzer. It measures impedance, resonance, and signal reflection across a frequency sweep. The original NanoVNA design is open-source hardware; Chinese clones are widely available for $25–35 on Amazon, AliExpress, or Banggood.

Look for a NanoVNA-H or NanoVNA-H4 — the H4 has a slightly larger screen and a wider frequency range, but either works for this experiment. Both sweep from 50 kHz to 900+ MHz, which is far more range than you need.

You'll also need a short SMA-to-alligator-clip cable or SMA-to-BNC adapter to connect the NanoVNA to your coil. These are a couple of dollars and usually come in the NanoVNA kit.

The core: ferrite toroid (~$5)

Get a Fair-Rite 5943003801 (or equivalent FT-37-43 / FT-50-43 mix-43 toroid). Mix 43 is a nickel-zinc ferrite optimized for the 20 MHz–250 MHz range — well above the frequencies we're measuring, which means the core won't saturate and confuse the results.

You can buy these individually from Mouser, Digi-Key, or in 10-packs from Amazon for under $10 total.

The wire: magnet wire (~$8)

Get a spool of 30 AWG enameled copper magnet wire (also called "winding wire"). A 200-foot spool is about $8 and will last you dozens of experiments. The enamel insulation is what makes the bifilar winding possible — the two wires sit right next to each other without shorting.

Supplies you probably already have

• A soldering iron (any temperature)
• A small piece of perfboard or just bare wire ends
• A ruler or calipers
• A notepad (or, better, a HiveJournal account to log measurements)

Total: ~$43 if you're starting from zero. If you already have a soldering iron, it's more like $35.

The build (30 minutes)

Step 1: Wind the conventional coil

Cut two lengths of magnet wire, each about 24 inches long. Strip about ½ inch of enamel from each end (a lighter flame works — hold the tip in the flame for 2 seconds, then wipe with a paper towel while hot; the charred enamel comes right off).

Take one wire and wind it around the toroid. Thread it through the center hole, around the outside, and back through — that's one turn. Do this 10 times, keeping the turns evenly spaced around the toroid. You now have a 10-turn conventional coil on a ferrite core.

Leave about 2 inches of wire on each end as leads.

Step 2: Measure the conventional coil

Connect the coil leads to the NanoVNA's CH0 port using your SMA-to-clip cable. Set the NanoVNA to sweep from 100 kHz to 30 MHz (this range is wide enough to capture the self-resonance of a 10-turn coil on a small toroid).

Look for the impedance peak — the frequency where |Z| is highest. That's the self-resonant frequency. On the NanoVNA, this shows up as a dip in the S11 (return loss) trace or a peak in the impedance display.

Record three numbers:

1. Self-resonant frequency (in MHz)
2. Impedance magnitude at resonance (in ohms)
3. Q factor — most NanoVNA firmware calculates this automatically, or you can estimate it as f₀ / bandwidth₋₃dB

Write these down. Take a photo of the NanoVNA screen.

Step 3: Wind the bifilar coil

Now take both wires — hold them parallel, touching each other — and wind them together around the same toroid, on the opposite side from the conventional winding (or use a second toroid if you prefer a cleaner comparison).

Wind 10 turns of the pair — same number of turns, same core, but now two wires go through each turn instead of one.

Here's the key part: how you connect the four wire ends matters. Label them:

• Wire A, start end = A1
• Wire A, finish end = A2
• Wire B, start end = B1
• Wire B, finish end = B2

Connect A2 to B1 (series-aiding configuration). Your measurement leads are now A1 and B2. This puts the two windings in series with their magnetic fields adding — Tesla's original configuration.

Step 4: Measure the bifilar coil

Same procedure as Step 2. Same frequency sweep. Same three measurements: self-resonant frequency, impedance at resonance, Q factor.

Take a photo. Write it down.

Step 5: Compare

You now have two sets of measurements on the same core, same number of turns, same wire gauge — the only variable is the winding geometry (conventional vs. bifilar series-aiding).

The questions the platform wants answered:

• Is the self-resonant frequency different? (Theory says yes — the inter-winding capacitance of the bifilar configuration should shift it.)
• By how much? (This is the data point that matters. A 10% shift is interesting. A 2x shift is very interesting.)
• Is the Q factor different? (Higher Q means less loss at resonance — more energy stays in the system.)
• Is the impedance at resonance different? (Higher impedance at resonance means the coil is a more effective energy storage element at that frequency.)

What to do with your results

1. Clone the template on HiveJournal — search for "Bifilar Coil Resonance Characterization" and clone it. The template has the full procedure, but now you've already done it.

2. Log your measurements in the clone's progress tracker. Include: core material, wire gauge, number of turns, NanoVNA model, all three measurements for both coils, and photos of the NanoVNA screen.

3. Submit a replication — once your measurements are logged, submit a replication on the template. Was the self-resonant frequency significantly different between the two configurations? Confirmed or refuted, either answer is valuable.

4. Add yourself to the map if you haven't already. You're now a citizen scientist. Welcome.

What happens when 50 people do this

Right now, the replication count on the bifilar coil experiment is zero. It's waiting for you.

When 50 different people — with 50 different NanoVNAs, 50 different toroids, 50 different gauges of wire, wound in 50 different garages — all report their measurements, we'll have a dataset that either confirms or refutes the hypothesis that bifilar geometry meaningfully shifts resonant behavior compared to conventional winding.

If confirmed across 50 independent replications, that's not anecdote. That's data. And it's data that feeds into the larger meta-pattern investigation: does resonance + non-linearity + pulsed excitation produce anomalous behavior when all three are present in the same system?

The bifilar coil experiment tests the first two. The pulsed excitation experiments come next. But this is where it starts — with a $5 toroid, some wire, and a cheap instrument.

The cost breakdown

If you already own a NanoVNA (or any VNA), the experiment costs about $16 in parts.

This is the first experiment. There are 28 more. Some cost more, some cost less, all are designed to be run on a workbench with commercially available components.

The question isn't whether any one person can build a breakthrough. The question is whether a thousand people measuring the same things, sharing everything, can assemble a picture that no one person could see alone.

Clone the experiment. Run it. Report what you find.