Modifying the loco frame
- Above the motor, but not lower than the top of the motor, provides an extra 1/8" clearance
- Above the front truck and drive shaft, while leaving clearance for the truck to swivel and tilt freely
- Above the rear truck and drive shaft, while leaving clearance for the truck to swivel and tilt freely
Highest priority is the battery. It is the largest component and determines operating duration between recharges. Since small speakers in well-designed enclosures provide good sound quality, it is a good trade-off to make speaker size our second priority. Radio receiver size can be modified by antenna choice and orientation.
S-CAB battery power supply, BPS
BPS battery, 850 mAh LiPo
Decoder, TSU-1000, model 827104
Speaker, Railmaster, DS1425-8
S-CAB receiver, cross-wise mounted antenna
- For good radio reception, avoid placing the radio antenna against a metal surface.
- The BPS turn-on sensor must be outside the range of magnetic fields created by motor and speaker.
- The speaker should be located so that the motor magnet does not interfere with speaker performance.
- To accommodate the speaker
- To create some air-space between antenna and metal frame.
The speaker is glued to a styrene plastic mounting that is attached to the frame with screws, which allows assembly to be removed for access to drive shaft and front truck. To complete this sub-assembly, the radio receiver will be mounted on back of speaker enclosure with adhesive or double sided sticky tape.
This arrangement leaves space above the motor for battery and decoder, neither of which is sensitive to the motor's magnet.
Tweaks to reduce component size
Tweaks to fit components in available space
S-CAB receivers are normally bundled back-to-back with the decoder, but an end-to-end arrangement fits more conveniently in this loco. Receiver and decoder are close together for this installation, but there is no limit to the length of wire between receiver and decoder.
Although the antenna cannot be separated from the receiver circuit board, there is a selection of different antennas and some can be oriented to suit the available space. This installation uses a ceramic chip antenna mounted "cross-wise".
Completing the project
Setting up the consist
At the conclusion of an operating session, the consist (or loco) is parked on a siding with track power to charge the battery and with F5 turned on. If later, the loco being charged is forgotten and track power turned off, F5 will immediately turn off loco batteries and prevent slow discharge from draining the battery. With battery power off, all loco electronics shut down, including the decoder, which will reset to its default state (F5 off) next time it turns on.
Comment: Some decoders save the state of their function outputs when shut down. Since this complicates using the decoder to turn off battery power, it's easier to initiate battery turn-off manually with a second on-board magnetic sensor.