ProRealAlgos
Indicators/probuilder · probacktest · proorder · proscreener

PRTBANDSUP

PRTBANDSUP returns the upper band of the proprietary PRT Bands volatility envelope in ProBuilder, used to detect breakouts and resistance. Syntax, examples.

Syntax

probuilder
PRTBandsUp

The instruction takes no arguments and returns the upper band value on the current bar.

Formula

The PRT Bands are proprietary to ProRealTime™ and the exact calculation is not published. The bands form an adaptive volatility envelope around price, similar in role to Bollinger or Keltner bands, but the underlying smoothing and width logic cannot be reproduced from public documentation. Treat PRTBandsUp as a platform built-in whose output can be consumed but not recomputed by hand.

How it works

On every bar, PRTBandsUp evaluates to the level of the upper envelope line that ProRealTime™ draws for its PRT Bands indicator. The band expands and contracts with market volatility, so its distance from price is not constant.

The upper band usually acts as a dynamic resistance reference. While price trades inside the envelope, the market is considered range-bound or in a mild trend. When the close breaks above the upper band, buying pressure has exceeded the recent volatility envelope, which breakout strategies interpret as the start or continuation of an upward move.

PRTBandsUp is almost always paired with PRTBANDSDOWN to monitor both edges of the envelope, and with PRTBANDSSHORTTERM or PRTBANDSMEDIUMTERM for the center lines. Because the instruction returns a plain numeric series, it can be compared, averaged, or offset like any other price-based value.

Examples

Example 1, Trend inversion detector with background colouring (Indicator)

probuilder
up = PRTBandsUp
dn = PRTBandsDown

if close crosses over up and trend <= 0 then
  trend = 1 // switch state to bullish
  r = 0
  g = 255
elsif close crosses under dn and trend >= 0 then
  trend = -1 // switch state to bearish
  r = 255
  g = 0
endif

signal = trend <> trend[1] // true on the bar where the state flips
backgroundcolor(r, g, 0, 50) // tint the chart by current state

return signal style(histogram) as "trend inversion", trend coloured(r, g, 0) as "trend direction"

The variable trend persists from bar to bar, so it only changes when the close crosses the opposite band. The histogram marks the exact bar of each inversion, and the background is tinted green or red to match the active state.

Example 2, Breakout entry system (ProOrder)

probuilder
DEFPARAM CumulateOrders = false

upper = PRTBandsUp
lower = PRTBandsDown

// Enter long when the close breaks above the upper band
IF NOT LongOnMarket AND close CROSSES OVER upper THEN
  BUY 1 CONTRACT AT MARKET
ENDIF

// Exit when the close falls back through the lower band
IF LongOnMarket AND close CROSSES UNDER lower THEN
  SELL AT MARKET
ENDIF

A minimal long-only breakout strategy. The full envelope is used, entry at the upper band and exit at the lower band, which keeps positions open through normal in-band noise.

Example 3, Screening for fresh upper-band breakouts (ProScreener)

probuilder
breakout = close CROSSES OVER PRTBandsUp
SCREENER[breakout](close AS "Last price")

Returns every instrument in the watchlist whose close crossed above the upper PRT Band on the current bar.

Interpretation

Price positionReading
Close above PRTBandsUpUpside breakout of the volatility envelope. Momentum strategies treat this as a long signal or trend confirmation.
Close between the bandsNo breakout. Price is contained within recent volatility.
Close below PRTBANDSDOWNDownside breakout, the bearish mirror case.

Band touches without a close beyond the band are weaker evidence than a confirmed cross. In sideways markets, crosses above the upper band frequently reverse, so breakout logic based on this band alone tends to whipsaw without an additional trend or volatility filter.

Common errors and gotchas

  • No parameters accepted. PRTBandsUp[20] or PRTBandsUp(close) raises a syntax error. The band periods are fixed by the platform, the instruction is written bare.
  • Proprietary formula. The band values cannot be recomputed manually or replicated on other platforms. Strategies built on PRT Bands are tied to ProRealTime™'s implementation.
  • Whipsaw in ranges. A close above the upper band in a sideways market often mean-reverts within a few bars. Combine with a trend filter such as a long moving average before trading breakouts.
  • Upper band alone is half the picture. Envelope logic normally needs both edges. Reading only PRTBandsUp while ignoring PRTBANDSDOWN discards the exit or short side of the signal.