KELTNER (Keltner Channels)

Keltner Channels use an EMA as the middle line with upper and lower bands offset by a multiple of ATR. They are smoother than Bollinger Bands because ATR is less volatile than standard deviation.

Declaration

function init(ctx) {
  ctx.indicator('keltner', 'KELTNER', { period: 20, multiplier: 2 });
}

Options

Option	Type	Default	Description
`period`	`number`	20	EMA and ATR period
`multiplier`	`number`	2	ATR multiplier for band width

Output

Returns an object with three series, accessed via underscore naming:

Property	Description
`upper`	Upper channel (EMA + multiplier x ATR)
`middle`	Middle line (EMA)
`lower`	Lower channel (EMA - multiplier x ATR)

Accessing Values

function onBar(ctx, i) {
  const upper = ctx.ind.keltner_upper[i];
  const middle = ctx.ind.keltner_middle[i];
  const lower = ctx.ind.keltner_lower[i];
}

Use Cases

Channel Breakout

function onBar(ctx, i) {
  const close = ctx.series.close[i];
  
  if (close > ctx.ind.keltner_upper[i]) {
    ctx.order.market('ASSET', 1, { signal: 'buy', reason: 'keltner_breakout' });
  }
  if (close < ctx.ind.keltner_lower[i]) {
    ctx.order.close('ASSET', { signal: 'sell', reason: 'keltner_breakdown' });
  }
}

Bollinger-Keltner Squeeze

function init(ctx) {
  ctx.indicator('bb', 'BBANDS', { period: 20, stdDev: 2 });
  ctx.indicator('kc', 'KELTNER', { period: 20, multiplier: 1.5 });
}

function onBar(ctx, i) {
  const bbInside = ctx.ind.bb_lower[i] > ctx.ind.kc_lower[i] && 
                   ctx.ind.bb_upper[i] < ctx.ind.kc_upper[i];
  
  // Squeeze: Bollinger Bands inside Keltner = low volatility
  // Expansion after squeeze = potential strong move
}

Calculation

Middle = EMA(Close, period)
Upper = Middle + multiplier x ATR(period)
Lower = Middle - multiplier x ATR(period)

Bollinger Bands - StdDev-based bands (more reactive)
ATR - Underlying volatility measure
Donchian - Price-range channel