* Posts by M0PLT

3 posts • joined 2 Jul 2018

East Midlands network-sniffer wails: Openreach, fix my outage-ridden line

M0PLT
Boffin

Re: It could be an EMC issue!

2.45 GHz and 5 GHz used for Wi-Fi are license-free Industrial, Scientific & Medical bands. They can be full of noise generated by ZigBee, Bluetooth, A/V senders, Baby monitors, and microwave ovens (at 2.45 GHz). Wi-Fi should not be seen as reliable or protected spectrum. Only a physical cabled connection - where practical - using Cat5/6 and clean Ethernet can be considered reliable. Powerline devices should be thrown in the nearest WEEE skip. They may not be affecting your radios. They will be affecting someone else's!

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M0PLT
Boffin

It could be an EMC issue!

There have been cases in the past where an entire village has suffered regular outages of their ADSL signals thanks to local REIN sources. Power-Line-Networking/Power-Line-Technology is a known cause of interference that leaks from the mains-wiring with the very same frequencies DSL services are trying to use (same modulation techniques). I wonder how many in the village are using Sky Q with the PLT switched on (as it is by default!)? Poorly maintained electric fences can also act as spark-gap transmitters which generate large regular wide-band electromagnetic pulses which affect the 3 to 30 MHz HF band. Openreach "engineers" I have spoken to do not know the first thing about EMC, or the hoards of junk electronics that can cause it. They are not going to find a REIN issue with a casual visit to the end-user's home; and neither with Ofcom with a casual drive-through as their equipment is not sensitive enough to pick-up the interference!

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Boffins want to stop Network Time Protocol's time-travelling exploits

M0PLT
Boffin

Re: Time NTP was upgraded(See what I did there!)

The GPS system is used to contribute to the accuracy of UTC. You can configure your NTP server to display UTC, or your local time zone. The Meinberg LANTIME M600 on my desk ticks away in UTC. I sat up to watch the last leap-second. There was a pause at 23:59:59 for 1 second to allow the planet to catch-up before the clock ticked over to 0:00. The NTP protocol can correctly handle leap-seconds - assuming the correct parts of the NTP protocol have been coded into your device. If the code-monkey skipped it as irrelevant, then yes, your computer/IoT crap will throw a wobbly!

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