[GLLUG] Charity WiFi, a bit off topic
cehunter at gb-x.org
Wed May 23 04:32:47 UTC 2018
On 22/05/18 23:01, James Holland via GLLUG wrote:
> On 26/03/18 17:56, John Winters via GLLUG wrote:
>> I've tried various brands of ethernet-over-mains devices and none of
>> them was reliable. They all seem to need to sit down for a rest
>> every hour or so, resulting in a couple of minutes of no connectivity
>> before they start working again. Really annoying if you're in the
>> middle of watching a film or something.
> To solve this I ping the AP every second. It works really well - much
> better than the repeater which I tested. I use LEDE (Openwrt) on the AP.
That was an approach that I tried too, but it didn't really help. It
prevented the Devolo and the TP-Link power-line efforts from going into
"sleep" mode, but didn't overcome the basic flakiness of the whole
power-line concept. I've used power-line communications since the 1960s
(I built a pair of 120kHz FM mains intercoms!), and it's OK for
non-critical applications. However, the general lack of reliability of
the medium, and the abysmal build quality of the equipment, conspire to
ensure that it'll never be reliable. Examination of several faulty
units (of various brands) show that there's always insufficient
isolation between the low voltage logic side of the circuit and the
mains side. The leakage figures on some of them were scary!
At one time, BT installations frequently included their power-line links
- particularly when BT-TV was involved. They'd arbitrarily throw these
things in, charge extra for them, and then blame the subscriber's
computer, mobile phone, TV, or even the weather for the appalling
performance of the BT "Infinity" service.
They really should be banned - the wideband RF noise from them jams
everything from Long Wave to the TV Bands. When I lived in London, I
paid for the installation of a couple of wired Ethernet links around a
neighbour's house so that I could get fairly reasonable radio reception
two doors away! They returned those "Netgear" jammers to PC World and
after a serious argument - which involved demonstrating that the DAB
radios on the shelf wouldn't work with the things plugged in, but were
fine when they were removed - the store manager realised that these
efforts weren't a good idea.
The RF noise we suffer these days from cheap and nasty Switched-Mode
PSUs, Ethernet over mains, Microwave Ovens, Induction Heaters and
Cookers, and all the rest is becoming a real nuisance. In most cities
we live in a kind of "Electro-smog", which increases the power budgets
for communications radio of all sorts, including PMR, Police, Fire and
Ambulance, microwave links, and all the rest. Everyone's having to
"shout louder" to make themselves heard!
Chris (in the Suffolk countryside!)
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