Volume momentum sync

Marks bars where price and volume both rose over the window; at default settings it never marks anything.

VolumeMomentumSync compares the close and the volume on each bar with the values window bars earlier, and scores a bar only when both are higher. The score averages two terms, each a rise divided by its own size plus 0.0001, so each term sits between 0 and 1 and the average never reaches 1. In practice the volume term is close to 1 for any volume rise of a few percent, so the price rise drives the score. A bar is marked when the score is above sync_threshold.

How to read it

Each marker sits on a candle where the close and the volume were both higher than window bars earlier. A candle with no marker failed that test or missed the threshold.
A marker needs both legs up: a price rise on falling volume, or a volume rise on a flat or falling price, draws nothing.
The default threshold of 1.2 is above anything the score can reach, so the chart stays empty until you lower sync_threshold.

What it outputs

Sync signal: The averaged score, drawn on bars where both price and volume rose over the window and the score cleared sync_threshold. The score runs from 0 up to just under 1.

When it fires

A bar where the close and volume are both higher than window bars earlier and the averaged score clears sync_threshold. The price rise over that span was large enough to clear the cut-off. It confirms an up-move; it does not call a reversal.

Settings

window: How many bars back the close and volume are compared against. Higher demands that price and volume rose over a longer stretch; lower reacts to the last few minutes. At 1 the comparison is with the bar itself, so the indicator never fires.
sync_threshold: The cut-off the score must clear. Because the score stays below 1, values of 1 or more never fire. Lowering it admits smaller price rises: 0.9 needs a rise of about 0.04% over the window, and 0.5 fires on nearly any bar where both are up.

Pitfalls

At default settings it never fires. The default threshold of 1.2 is unreachable, so the indicator looks broken until the threshold is lowered. On SPY one-minute bars for September 2026 it marked 0 of 20,160 bars.
The volume leg is nearly always close to 1, so volume mostly acts as a gate: it has to be higher than window bars earlier. The price rise sets the score.
The marker says price and volume rose together over the window. It does not forecast direction after the marker, so do not read it alone as a buy or sell signal.