Television Interference 868 MHz

A couple of months ago I put an 868 MHz Meshtastic node on the top floor of my house.

I always had bad TV reception where I live. By coincidence, that same weekend I put a new high gain TV aerial in my attic which was probably about 1 m above and 3 m horizontally from the node.

Since then, my TV reception was so bad it was pretty much impossible to watch digital terrestrial TV. I assumed it was just that the new aerial wasn’t as good as its specs or not perfectly aimed, but I didn’t really think about it because I hardly watch any TV.

Anyway, last night I switched off the node and all of a sudden TV reception was perfect. I double checked a few times and confirmed the node was the cause.

I was a bit surprised as all the TV channels I receive are 474 - 690 MHz. (The node’s power supply was not the cause.) Just thought I’d mention it.

You might be affected by harmonic radiation.

Harmonic radiation occurs when a system, such as an antenna or electronic circuit,
emits radiation at frequencies that are integer multiples of a fundamental frequency.
Essentially, if the fundamental frequency is ff, then harmonic frequencies are 2f2f, 3f3f, 4f4f,
and so on.
This can happen due to non-linearities in the system that cause it to generate signals at these higher frequencies.

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