08/20/05 (UPDATED 12/17/2010)
MTH TIU Antenna Add-on Modification to Extend MTH DCS Handheld Remote Operation Range:
Background of operation: The MTH DCS (Digital Command Control System) utilizes: (1) a wireless handheld remote with LCD screen and (2) a base receiver & track interface called a TIU. (There is a third device, an AIU, for accessories) The TIU goes between the output of an AC / DC power supply and the power lines that goes to the track. The TIU accepts the wireless signal from the handheld remote and converts it into a digital signal that is fed with the power through the track to the MTH DCS equipped engine(s). The wireless remote is supposed to have a 50ft operating range.
In operation (with my TIU located inside the basement) I was getting an actual range of between 10-40 feet outside depending on where you were.
In testing I found that adding to the length of the existing TIU antenna would yield a much better range and have the steps noted below.
Lengthening the TIU antenna
NOTE: Be sure to stay grounded when attempting this modification so as not to risk a static discharge to the TIU antenna.
- Flip the TIU upside down and remove the 6 screws holding the top and bottom pieces together and remove the top cover.
This photo shows the top of the TIU main board with short antenna that comes with the RF transmitter board. (This has a solderless connector added on the end during early stages of my testing.)
- Solder a wire to the end of existing antenna wire so that the total length is about 12.88 inches long. (the original is ~3.125" and the new extension should be ~9.76" in additional added length...if you figure about .25" in overlay in soldering the two antennas together then your new wire should be ~10" long) (12.88" is precise length for a full wave antenna at the 916.5 Mhz frequency) I found that the best wire to use is the thick solid copper core wiring used in house wiring, and in my case use the bare ground wire and keep it straight. (You will want to try and keep the wire standing relatively straight up.)
- Use heat shrink to insulate the new connection between the two antenna wires
- Drill out a small hole between two of the vent grills so you can push the new antenna through
- Reattach the top cover of the TIU.
- In this case I used a small amount of hot glue at the base of the antenna to keep it securely in place and standing standing straight up and to eliminate flex of the internal antenna connection
- Note: if you want to use just a bare wire for maximum reception, be sure to not touch the antenna and risk a static discharge as that could be harmful to the RF transmitter. For more protection, you could use a wire with an insulator or (as I have done) slide on a length of heat shrink.
One thing, fresh 1.5v alkaline batteries can yield a little better range than the 1.2v rechargeables, but with this mod you shouldn't need them.
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