DCC wiring question

[billyboy]

This should be an easy one

 

My main run is a loop with a spur off to one side for the station but the question on the running loop is do I create a electrical loop for the DCC but or just terminate at a point?

 

Bill

[richrua]

As far as I know, which others may disagree with, you don't need your bus for DCC in a loop or circle to follow the track. According to a bit of reading from various folks, a star type bus is preferred. In fact some advise against a complete loop .

[richrua]

This page explains it very well.

 

http://www.brian-lambert.co.uk/DCC.html

[Noel]

As far as I know, which others may disagree with, you don't need your bus for DCC in a loop or circle to follow the track. According to a bit of reading from various folks, a star type bus is preferred. In fact some advise against a complete loop .

 

I use star because that is the way the layout had been wired for DC, now I just leave all section blocks turned on and the four stars (i.e. one for each loop) are joined in parallel at the main junction box. Easy to switch back to DC mode for occasion runs of older locos using DPDT switches between DCC controller and DC controllers.

[irishthump]

As far as I know, which others may disagree with, you don't need your bus for DCC in a loop or circle to follow the track. According to a bit of reading from various folks, a star type bus is preferred. In fact some advise against a complete loop .

 

It's best not to have a loop. I believe the simple explanation is that the signal from the controller goes out along the bus and in a loop the signal will effectively "double back" on itself whish can" confuse" decoders.

[billyboy]

Fair enough suspected as much, the opinions of those older and wiser than me always welcome.

 

Thanks lads.

[Dave]

It's best not to have a loop. I believe the simple explanation is that the signal from the controller goes out along the bus and in a loop the signal will effectively "double back" on itself whish can" confuse" decoders.

 

That's a bit of a myth, if your track is a loop it returns back on itself anyway.

[richrua]

... You know, I suppose it does!!!!

[WRENNEIRE]

This page explains it very well.

 

http://www.brian-lambert.co.uk/DCC.html

 

Jasus, that Lambert fella has a lot of spare time on his hands...

[irishthump]

That's a bit of a myth, if your track is a loop it returns back on itself anyway.

 

Recommended practice is to place insulated joiners in the loop of track at roughly the same point as the gap in the bus. The problems a looped bus can cause mainly effect large layouts, but they can cause issues in small layouts that might seem intermittent. On my old layout which had a main loop of roughly 20ft x 4ft I had an issue where some locos wouldn't respond to commands straight away. It dawned on me that it would happen at roughly the point that was furthest from where the bus connected to the command station. I cut the bus loop and gapped the track and the problems disappeared.

[BosKonay]

You can also fit DCC bus terminators / filters (DCC supplies and I think gaugemaster make some, or you can DIY) which will help maintain a clean signal.