Here is the code of the Bollinger Bands:

period = 20
dev = 2.0
data = customclose
MA = average[period](data)
BolUp = MA+STD[period]*dev
BolDn = MA-STD[period]*dev

RETURN BolUp, BolDn

I know this is an “old” post, but I react anyway:

Maybe the difference is in the MA. PRT uses expMovAv (exponentialAverage) and Nicolas uses SimpMovAv (Average) I think.

Gr. Pieter

Hi Nicolas,

I don’t have the PRT code, but I just compared the PRT BB and your BB in one chart and saw a different outcome.

Then I changed your BB SimpMovAv  into a expMovAv, and the outcome was the same as the PRT BB. So then I knew.

I now made a combination indicator with BB and Keltner (both with the same SimpMovAv) so that I can easily change the periods, the BB deviation and the Keltner ATR-percentage with one action without opening the probuilder. (therefor  you have to create indicator parameters named “per” (period) “dev” (BB deviation) and “ATR” (ATR-percentage)

Pieter

// you have to create indicator parameters named "per" (period) "dev" (BB deviation) and "ATR" (ATR-percentage)

period = per
dev = dev
data = customclose
MA = average[period](data)
BolUp = MA+STD[period]*dev
BolDn = MA-STD[period]*dev
 
MiddleMovingAverage=Average[per](close)
UpperKchannel=MiddleMovingAverage+ATR*AverageTrueRange[per](high)
LowerKchannel=MiddleMovingAverage-ATR*AverageTrueRange[per](low)



RETURN bolup as "BOLsim++", ma as "BOLkeltMA",  BolDn as "BOLsim--",     UpperKchannel AS "KeltSim hi",LowerKchannel AS "KeltSim Lo"