What do the lines on the TDI represent?

The fast line (often green) is a short moving average of RSI, the signal line (often red) is a slower one, the base line (often yellow) is the midline of Bollinger Bands computed on RSI, and the outer bands mark that RSI's volatility envelope. Colors and exact periods vary by platform, but the roles stay consistent.

Is the TDI better than using RSI alone?

It presents the same underlying data with more context, not more information. The smoothing and bands make crossovers and volatility squeezes easier to see, at the cost of extra lag and more rules to manage. Whether that helps depends on the trader and market; nothing in the construction makes its signals inherently more reliable than a plain RSI.

What are the standard TDI settings?

The classic stack is a 13-period RSI, a 2-period fast line, a 7-period signal line, and 34-period bands at roughly 1.6185 standard deviations. Ports vary the smoothing types and occasionally the band multiplier, which changes the feel more than the substance. As with most composites, consistency matters more than the specific numbers: the reads are learned patterns, and they only accumulate meaning under stable settings.

What is a TDI shark fin?

Community vocabulary for a sharp spike of the fast line outside an outer band that immediately snaps back inside, drawing a fin shape. It is read as an exhaustion event: momentum overshot its own recent volatility envelope and failed to hold there. Like all TDI patterns it is an RSI behavior wearing a memorable name, and it earns trust only at meaningful price locations, not floating in the middle of a range.

Why is the band multiplier 1.6185 instead of 2?

It came that way from the original release, a golden-ratio-styled choice, and the convention stuck. Practically, narrower bands make band touches and breaks more frequent, tuning the panel toward earlier but noisier volatility reads than standard Bollinger settings would give. There is no statistical case for the specific number; treat it as part of the indicator's learned visual grammar rather than as mathematics.

Is the TDI a complete trading system?

It is marketed that way, and it does bundle trend, timing and volatility reads into one pane. But every read derives from a single RSI stream, so the panel cannot supply what that stream lacks: price structure, levels, volume behavior, and higher-timeframe context. Traders who use it well typically treat it as the momentum module inside a larger process, letting location decide where the TDI's timing grammar is allowed to fire.

Concept

Traders Dynamic Index

Traders Dynamic Index is a Momentum & Oscillators concept. The Library holds 1 implementation, a working definition you can pull into Quant.

TDI

Top Traders Dynamic Index indicator

The top custom implementation, built on the original standard Traders Dynamic Index formula.

1 total

The Traders Dynamic Index implementation below can become a backtested trading strategy — describe your rules and Quant writes the code.

Traders Dynamic Index

Indicator

What is the Traders Dynamic Index?

The Traders Dynamic Index (TDI) is a composite momentum indicator, developed by Dean Malone, that layers several readings into one pane. Its base is an RSI, commonly 13-period. On top of that it plots a fast moving average of the RSI (the price line, often 2 periods), a slower one (the signal line, often 7), and Bollinger Bands calculated on the RSI itself: volatility bands around a market base line, commonly on a 34-period basis.

The design intent is a single window that answers three questions at once: the RSI supplies momentum direction, the two moving averages supply crossover timing, and the bands supply a volatility envelope for the momentum reading. It became popular in forex trading as an all-in-one panel, though every component is a smoothed derivative of the same RSI series, so its lines confirm one another more than they independently verify anything.

The classic release carried some distinctive conventions that ports mostly preserve. The bands are usually drawn at 1.6185 standard deviations rather than the Bollinger default of 2, a golden-ratio-flavored choice from the original that has no demonstrated statistical edge, and the community grew a vocabulary around the shapes: lines braided flat around 50 read as a dead range, the price line riding an expanding band marks a strong push, and the sharp poke outside a band that immediately folds back, the shark fin, is read as an exhaustion spike. The grammar is genuinely convenient; it is also all one RSI stream wearing four costumes.

Modern Library versions extend the panel rather than the math: LazyBear's early port established the baseline, and later builds like thienlovv's and ZyadaCharts' add automated divergence detection and packaged buy/sell arrows on top of the classic lines. The honest framing for all of them is that the TDI is a well-organized RSI dashboard: it makes the state of one oscillator unusually readable, which has real workflow value, while structure, levels and volume still have to come from somewhere else.

How to identify the TDI's components

Five plots, one source. Identifying the TDI means tracing each line back to the RSI it decorates.

1Start at the base: a 13-period RSI computed on price; every other element derives from this series.
2The price line: a very fast moving average of the RSI, classically 2 periods, supplying the twitchy lead trace.
3The signal line: a slower average, classically 7 periods, giving the crossover partner.
4The base line and bands: a 34-period average of the RSI flanked by bands near 1.6185 standard deviations, framing the momentum stream's own volatility.
5Read the state machine: crossovers time entries, the 50 region splits bull from bear regime, band pinches mark contraction and band rides mark strong trends.

How it's calculated

TDI plots an RSI together with its own smoothed signal lines and volatility bands so momentum, trend, and volatility read from one panel.

\operatorname{RSI}_t = 100 \times \frac{\mathrm{AvgGain}_t}{\mathrm{AvgGain}_t + \mathrm{AvgLoss}_t}

\mathrm{PriceLine}_t = \operatorname{SMA}(\operatorname{RSI}, a)

\mathrm{SignalLine}_t = \operatorname{SMA}(\operatorname{RSI}, b)

\mathrm{BaseLine}_t = \operatorname{SMA}(\operatorname{RSI}, c)

\mathrm{UpperBand}_t = \mathrm{BaseLine}_t + m \times \operatorname{StdDev}(\operatorname{RSI}, c)

\mathrm{LowerBand}_t = \mathrm{BaseLine}_t - m \times \operatorname{StdDev}(\operatorname{RSI}, c)

t: bar index

RSI_t: relative strength index of the close over p bars

AvgGain_t: Wilder smoothed average of up moves max(close_t - close_{t-1}, 0) over p bars

AvgLoss_t: Wilder smoothed average of down moves max(close_{t-1} - close_t, 0) over p bars

p: RSI period (default 13)

SMA(x, n): simple moving average of series x over n bars

StdDev(x, n): standard deviation of series x over n bars

a: price line period (default 2)

b: signal line period (default 7)

c: base line and band period (default 34)

m: band width multiplier (default 1.6185)

PriceLine_t, SignalLine_t: fast RSI line and its slower trade signal line (green and red in the original)

BaseLine_t: market base line, the midline of the bands (yellow)

UpperBand_t, LowerBand_t: volatility bands, Bollinger Bands computed on the RSI series (blue)

Defaults are Dean Malone's original settings: RSI 13, price line 2, signal line 7, bands 34 with multiplier 1.6185.

Typical readings use price line versus signal line crosses for entries, both lines versus the base line for trend, and band width for volatility.

Some platforms offer EMA smoothing options or a population standard deviation, which slightly changes band width.

How traders use it

As a crossover trigger: the fast price line crossing the slower signal line is the classic TDI entry cue, usually filtered by whether both sit above or below the 50 midline.
As a volatility read: the price line pressing an outer band marks stretched momentum, while pinching bands signal contraction that often precedes a stronger directional move (not a guaranteed one).
As a regime filter: the market base line's position and slope relative to 50 is used to permit longs, shorts, or neither, functioning like a bias check before any crossover is taken.
As a divergence panel: because the price line is a lightly smoothed RSI, classic and hidden divergences against price are read directly off the TDI, and several ports annotate them automatically.
With zone grammar: excursions into the outer RSI zones, commonly 68 and 32 on the TDI scale, add an overbought/oversold layer, most useful when a zone touch coincides with a shark-fin poke outside the band.

TDI vs related momentum tools

RSI: The TDI is RSI with staging: smoothed copies, a slow baseline and a volatility envelope, all computed on the oscillator itself. Nothing in the dressing adds independent information; what it adds is readability, turning RSI's single squiggle into an organized state display.

Stochastic RSI: Both are RSI derivatives with opposite temperaments: Stochastic RSI stretches the oscillator to amplify sensitivity, accepting noise, while the TDI smooths and frames it to emphasize regime and timing, accepting lag. One turns the volume up, the other tidies the room.

MACD: MACD builds its crossover grammar from price-based averages; the TDI builds an equivalent grammar from RSI-based ones. The reads rhyme, fast-slow crosses and centerline regime, but MACD is unbounded and price-anchored while the TDI inherits RSI's 0-100 cage and its saturation behavior.

Concept family

Momentum & Oscillators

91 concepts mapped · 91 in the Library