MCC & Cars

High pitched whistling noise from UCCI transmission loop

I'm in the process of switching from my "test" layout to my permanent layout. The new layout is much larger (around 15 metres of road in total). I have split the layout in two and am using both transmission loops on the UCCI.

I can hear a high frequency whistling noise coming from both of the the transmission loop. This wasn't present on my smaller test layout. The vehicles respond perfectly and obey all commands.

Has anyone else had this issue? Many thanks in advance.

Quick update: it seems to be proportional to the loop current setting. Reducing it to 200mA makes it a lot quieter but the noise is still there.


Hi Andrew,
The noise decreases while you get older.
More serious: the modulated current through the wires generates a modulated magnetic field that generates a physical force on the wires. What you hear is the resulting movement.
You may mimimize this by fixing the wires by glueing, however this may be quite some work. It depends on how irritating you find the noise wether you want to do that.
Anyway it does not mean anything is wrong.

Best regards, Leon

Hi Leon,

Many thanks for your help with this. You're right - it does sound like an old fashioned television!

I'm still testing the transmission loops and servos and have not applied a road surface yet. See the attached photo (with thanks to James at DCC Train Automation for the laser-cut roads).

The transmission loops are glued to the road along its full length. I'll reduce the transmission loop current to the lowest level that still works, as this reduces the noise.

I'll also experiment with applying some road surface plaster, as this will hopefully hold the wires in place and stop some movement. I'll let you know how I get on.


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