Friday, 31 May 2013

QRM - It is a very noisy Friday

My last post was about the joys of SDR, this one is about the bane of not only SDR but radio in general namely the amount of electromagnetic rubbish that is thrown into the ether by shoddy equipment, with SDR you just see just how much s**t there is.

These are some waterfalls captured today, first exhibit showing lovely evenly space spikes, and a mass of hash and splatter.

A little further up the spectrum, another splatter, this I am convinced is some form of Power Line Network Adapter. You know the ones someone thought was a clever and expensive solution to that problem "How do you get network data from one room to another without the hassle of running a cheap proper shielded network cable or using wifi?" Their answer was to use unshielded mains wiring to transmit data at radio frequencies turning them into efficient antennas!

Mind you even using shielded network cabling isn't always the answer especially if you have cheap probably Chinese made network equipment which some one is using nearby. It generates this pretty pattern right across the VHF 2 meter band, especially bad on 144MHz.

Hold on VHF is immune to PLA interference you say? Yeah right!

I have posted before about problems I have had before including some videos including the one below. Thanks to my direction finding skills I know which direction this annoying interference was coming from, but I haven't seen it for a while, someone got themselves a new Plasma/LCD TV?

I am aware some of my equipment generates some noise, but even powering down the entire house and running on laptop batteries I see just as much rubbish, rubbish that disappears as soon as you remove the antenna.

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