Someone explain D-Tech rotators for me

ryan

Member
May 20, 2010
2,996
Massillon, Ohio
early on in the start they were 2 pieces of plastic with a special coating on them, one side red or blue, the other amber or blue. when they were off they were clearish, when on they reflected the light thru the coating. now they use colored glass to to reflect the light.
 

shues

Lifetime VIP Donor
May 21, 2010
10,286
NW Indiana
The old plastic D-Tech rotators did not hold up very well. The coating flakes off and your lightbar becomes filled with glitter while the emitted light becomes less red or blue and more white. However, the new glass D-Tech rotators are a marvel. The work wonderfully.


Also, fast rotators are fine for standard halogen bulbs with colored filters, but D-Techs are only useful on slow rotators.
 

Richard P

Member
May 23, 2010
1,031
Sudbury, On
Theyre simply a 2 way mirror. its 2 glass rotator reflectors together joined face to face, you can see through the rear of them, but the inside is a mirror.


one side is colored red, the other blue. as the red reflector faces you, the inside of the blue is a mirror, and when it rotates to blue facing you, the inside of the red is a reflector.


http://www.youtube.com/watch?v=qWQAqx_Q ... re=related

 

nerdly_dood

Member
Jun 15, 2010
2,312
Georgia
Never ever use D-tech rotators with a fast motor - if you do then it'll be producing 350 FPM from a single light, which is just too much for a rotator to be effective. When using it with a slow motor, it produces 190 FPM which is slightly more than a standard rotator with a fast motor, which produces 175 FPM. Don't bother using D-tech rotators with a clear lens under colored domes, you would produce a very similar flash effect with normal rotators with a fast motor. The purpose of a D-tech rotator is to produce two different colors of light from the same bulb.


A Whelen RB6 dual-beam version uses a similar method with one 65w bulb and a dual-sided reflector to produce 50,000 candlepower at 130 FPM.
 

Shawn L

Member
May 21, 2010
2,477
Corbett, Oregon
stay away from the plastic, they get brittle and flake really bad.... trust me Portland police used d-tech's for years, glass is the only way to go
 

Doug

Member
May 23, 2010
1,151
Maryland
nerdly_dood said:
Never ever use D-tech rotators with a fast motor - if you do then it'll be producing 350 FPM from a single light, which is just too much for a rotator to be effective. When using it with a slow motor, it produces 190 FPM which is slightly more than a standard rotator with a fast motor, which produces 175 FPM. Don't bother using D-tech rotators with a clear lens under colored domes, you would produce a very similar flash effect with normal rotators with a fast motor. The purpose of a D-tech rotator is to produce two different colors of light from the same bulb.

A Whelen RB6 dual-beam version uses a similar method with one 65w bulb and a dual-sided reflector to produce 50,000 candlepower at 130 FPM.

I thought Code 3's standard speed rotators were 100 RPM, and their fast were 200 RPM. Federal's rotators are 95 RPM for the standard, 120 RPM for the medium and 175 RPM for the fast.


I agree about using the D-Tech only on the standard/slow rotators; otherwise, they appear only as a blur.
 

luckyducky

Member
May 22, 2010
262
NorCal
Shawn L said:
stay away from the plastic, they get brittle and flake really bad.... trust me Portland police used d-tech's for years, glass is the only way to go

I am trying to restore an MX with NOS R/B D-techs I want one B/A.
 

nerdly_dood

Member
Jun 15, 2010
2,312
Georgia
Doug said:
I thought Code 3's standard speed rotators were 100 RPM, and their fast were 200 RPM. Federal's rotators are 95 RPM for the standard, 120 RPM for the medium and 175 RPM for the fast.
I don't know what the speed is for sure, they only say "standard" or "fast" - I'm just taking FedSig's example.
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
I always thought the blue/amber was pointless.... who runs amber blue 360? I'm sure someone does.... I just hate amber to the front on emergency vehicles.
 

cutiger

Member
Jun 11, 2010
370
SC
JohnMarcson said:
I always thought the blue/amber was pointless.... who runs amber blue 360? I'm sure someone does.... I just hate amber to the front on emergency vehicles.
If I see amber I think construction/dot/road service. I think it should only be used for rear warning and only rear warning in other vehicles.
 

shues

Lifetime VIP Donor
May 21, 2010
10,286
NW Indiana
A blue/blue D-Tech, or any D-Tech in only one color, would accomplish nothing. For that application, a normal rotator with a colored filter would be indicated.


A D-Tech works by letting one color of light through one side of the filter, while reflecting all the rest of the colors of light back at the other side of the filter. I imagine a blue/blue D-Tech would emit very little light, would have a diminished or dull flash, and that the light would not fill the D-Tech in the same way it fills a normal D-Tech.
 

Richard P

Member
May 23, 2010
1,031
Sudbury, On
JohnMarcson said:
I always thought the blue/amber was pointless.... who runs amber blue 360? I'm sure someone does.... I just hate amber to the front on emergency vehicles.

Blue/ amber is snow plows here, that would be a useful bar here
 

cbratt

Member
May 21, 2010
29
Idaho
You must run the RED/BLUE config. I tried to split them up and make a blue/blue - red/red set up....it didn't work...the colors were REALLY washed out and the glass looked like the old plastic lenses.....i switched them back.


I put two fast rotators on the outboard sections on my D-Tech bar....and they get a lot of attention....but any faster and you'd loose color shift.
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
Richard P said:
Blue/ amber is snow plows here, that would be a useful bar here


I guess there is at least one legit use for blue amber... :eek:
 

EL1998P71

Member
May 23, 2010
704
Sterling Heights Mich
Doesn't ADOT (Alaska Dept of Transportation) use amber and blue for their road vehicles and plow trucks?


There was an epsiode of Dangerous Drives on Speed channel that showed plow trucks with amber and blue strobes and pick up trucks with amber and blue LED's.


Red/red or Blue/blue D-Tech's are pointless, you'd be better off with a color dome.


And you loose the POP of the reflector.


Auburn Hills, MI used 360's with D-Techs in place of the intersection sweeps.


The upper lights were much brighter over the lower D-techs


In certain uses I could see using a D-tech, but an fully loaded bar with only D-Techs is not an effective use of a lightbar.
 
May 21, 2010
1,591
Berlin, MI, 48002
EL1998P71 said:
Auburn Hills, MI used 360's with D-Techs in place of the intersection sweeps.


The upper lights were much brighter over the lower D-techs


In certain uses I could see using a D-tech, but an fully loaded bar with only D-Techs is not an effective use of a lightbar.

I ended up with most of those bars & they had the plastic / flaky D-Techs. I think they would've been better off with an MX-style single sweep.
 

StLFC-Mike

Member
May 24, 2010
23
SouthEast Wisconsin
IIRC, the D-Tech choices were either red/blue or blue/amber.


The theory behind it is kind of like a filter that does not absorb the non-selected color rather it reflects it at the other colored element. Because of this, a red/amber version would be a poor performer due to yellow being a composite color of red.


Havent seen them by me in quite a few years, wasn't impressed with them as the colors blurred and were washed out.


Technically they are illegal in WI.
 

Maranos

Member
May 21, 2010
151
Pacific Northwest, USA
Shawn L said:
stay away from the plastic, they get brittle and flake really bad.... trust me Portland police used d-tech's for years, glass is the only way to go

They still do in fact. Tho the majority of their fleet sports the C3 2100 or the Liberty now, I still occasionally see one with the d-tech's cruising the streets. Before they migrated to the glass d-tech's I was able to get my hands on one of the old plastic versions that was being retired. As you can see just not as bold of colors due to wear. In fact the one on the very left end is supposed to be R/B but it looks more W/A now due to fading. And for whatever reason Portland did S F F F S for rotator speeds, fast d-techs are definitely pointless as posted above.

 

Forum Statistics

Threads
54,052
Messages
450,127
Members
19,141
Latest member
pcrose

About Us

  • Since 1997, eLightbars has been the premier venue for all things emergency warning equipment. Discussions, classified listings, pictures, videos, chat, & more! Our staff members strive to keep the forums organized and clutter-free. All of our offerings are free-of-charge with all costs offset by banner advertising. Premium offerings are available to improve your experience.

User Menu

Secure Browsing & Transactions

eLightbars.org uses SSL to secure all traffic between our server and your browsing device. All browsing and transactions within are secured by an SSL Certificate with high-strength encryption.