LazyBear

DEnvelope [Better Bollinger Bands]

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Bollinger Bands (BB) usually expand quickly after a volatility increase but contract more slowly as volatility declines. This extended time it takes for BB to contract after a volatility drop can make trading some instruments using BB alone difficult or less profitable.

In the October 1998 issue of "Futures" there is an article written by Dennis McNicholl called "Better Bollinger Bands", in which the author recommends improving BB by modifying:
- the center line formula &
- different equations for calculating the bands.

These bands, called "DEnvelope", follow price more closely and respond faster to changes in volatility with these modifications.

Fore more indicators, check out my "Master Index of indicators" (Also check my published charts page for new ones I haven't added to that list):

More scripts related to DEnvelope:
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- DEnvelope Bandwidth: http://pastebin.com/jz6QL45G
- DEnvelope %B : http://pastebin.com/r4XfrDvd

Sample chart with above indicators: https://www.tradingview.com/v/dK1uhbN8/#...

List of my free indicators: http://bit.ly/1LQaPK8
List of my indicators at Appstore: http://blog.tradingview.com/?p=970
Open-source script

In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.

Disclaimer

The information and publications are not meant to be, and do not constitute, financial, investment, trading, or other types of advice or recommendations supplied or endorsed by TradingView. Read more in the Terms of Use.

Want to use this script on a chart?
//
// @author LazyBear 
// List of all my indicators: https://www.tradingview.com/v/4IneGo8h/
//
study("DEnvelope [LazyBear]", shorttitle="DENV_LB", overlay=true)
lb=input(20, title="DEnvelope lookback length")
de=input(2, title="DEnvelope band deviation")
alp=2/(lb+1)
src=hlc3
mt=alp*src+(1-alp)*nz(mt[1])
ut=alp*mt+(1-alp)*nz(ut[1])
dt=((2-alp)*mt-ut)/(1-alp)
mt2=alp*abs(src-dt)+(1-alp)*nz(mt2[1])
ut2=alp*mt2+(1-alp)*nz(ut2[1])
dt2=((2-alp)*mt2-ut2)/(1-alp)
but=dt+de*dt2
blt=dt-de*dt2
plot(but, color=red, linewidth=2)
plot(dt, color=gray)
plot(blt, color=green, linewidth=2)