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The Wi-Fi only works when it's raining

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Re: The Wi-Fi only works when it's raining

#271

Post by ozim »

rawbot wrote: post #254
ozim wrote: post #249

Earlier quoted context omitted.

Love that story. For me it reminds me most debugging I see at work. People coming up with theories and doing some magic incantations on the interface. Instead of reading the log files or reading error description which makes usually error and fix obvious in 10 seconds.

Reading log files with really obscure error messages might as well be reading a magical grimoire. Especially when the solution turned out to have nothing to do with the error message.

Hey but that is not a discussion, that's just throwing anecdote to bring other person down or make yourself feel better.

Re: The Wi-Fi only works when it's raining

#272

Post by 9935c101ab17a66 »

The author’s completely over the top reaction to the plausible and not especially weird titular statement gets old, quick.

Especially when they reveal that the network is using wifi antennas over a non-insignificant distance in an urban setting. Of course it’s the local wireless point to point bridge! The first thing you’d do is look down the line of sight for interference.

Re: The Wi-Fi only works when it's raining

#274

Post by taneq »

mikegreenberg wrote: post #69
asadhaider wrote: post #33

Earlier quoted context omitted.

First thing I thought of too. Anyone know if there a list of more articles similar to these three?

I have one first-hand story: I did tech support via phone for a popular consumer computer brand. One particular call, a woman reported that her computer was restarting every time someone in the house flushed the toilet. Long story short, her home was in the back-back woods with the home powered by a generator. In addition to powering the computer, the generator was also the source of power for a water pump which woul…

I have a similar one, with an automated monorail hoist. The engineer who started the job had ordered the monorail hoist with a control cabinet with Ethernet comms to tell it where to move (instead of just controlling the hoist directly from the main control cabinet.) After days' worth of shenanigans trying to troubleshoot seemingly random comms drop-outs I'd narrowed it down to only occurring when the hoist was being lowered under load, which led me to the Ethernet cable in the hoist cabinet which ran parallel to the motor cables from the hoist's 6kW VSD. Whenever it lowered, the EMI was enough to nuke the Ethernet connection. Re-routed the Ethernet cable and after that it ran fine.

Re: The Wi-Fi only works when it's raining

#278

Post by tomaskafka »

koyote wrote: post #195

One of my most recent 'weird internet issues' was when I upgraded our 50mbit internet connection to 100Mbit and my laptop never really reached 100Mbit whereas my homelab easily got 100Mbit on speed tests. It took me a while to realise the difference was that the homelab was physically connected and the laptop was using Wifi. The laptop wifi was connected to the AP at ~1.2 Gbit and a different machine had the same iss…

Dtto for video cables - once you get into 1440p/4k and high frequency rates or VBR, that HDMI 2.1 or DP 1.4 certifications start to actually matter.

What is worse is that the hardware tries hard to make it work even with noncompliant cable resulting in things like random flashes of black, or multiple random reconnections after plugging in the laptop.

Re: The Wi-Fi only works when it's raining

#279

Post by ColinWright »

swores wrote: post #252
Sharlin wrote: post #156

Earlier quoted context omitted.

Well, you can't just ignore a radar shadow or noise. Just like GP's point-to-point microwave link couldn't just "ignore" the crane. You can't make a bad Wi-fi connection faster by just telling your computer to ignore the wall between you and the hot spot. A wind turbine is a solid obstacle that conceals stuff behind it, and even if a single turbine might not be a big deal, most commonly someone interested in harnessi…

My (probably ignorant) thinking was that if there weren't propellers, just stalks, they could be arranged in a pattern that radar setups at multiple locations could see through gaps and between them have no dark spaces caused by the towers. Leaving the problem that the blades essentially block out an entire circle, but if the radar software knows the position of every turbine's blades (by a combination of turbines re…

Radars work in the 3cm or 10cm ranges[0], so you'll always get a return from the towers and the blades, and that significantly reduces the energy that gets beyond the turbine to illuminate potential targets.

Reflections from targets also need to pass the turbine(s), reducing the return even more.

Beamwidths are significant, depending on the antenna configuration. You can have beamwidths of 0.5 degrees and more. That helps detection, but reduces target discrimination. It helps get the energy past the turbines, but you tend to have "wound down" the power output to allow for that. So it doesn't really help.[1]

You know where the turbines are ... knowing the exact positions of the blades won't help at the frequencies being used.

In short, it's complicated. Radar pulses are like HUGE lumps of energy flying through space, and delicate things like turbine blades chop them up and defect them around, preventing them from getting to, and then from, the targets.

[0] Marine radars, X-Band and S-Band. There are other ranges and bands.

[1] Yes, this is all extremely simplified and inaccurate, but I'm trying to give a sense of what's going on.

Re: The Wi-Fi only works when it's raining

#280

Post by swores »

ColinWright wrote: post #279
swores wrote: post #252

Earlier quoted context omitted.

My (probably ignorant) thinking was that if there weren't propellers, just stalks, they could be arranged in a pattern that radar setups at multiple locations could see through gaps and between them have no dark spaces caused by the towers. Leaving the problem that the blades essentially block out an entire circle, but if the radar software knows the position of every turbine's blades (by a combination of turbines re…

Radars work in the 3cm or 10cm ranges[0], so you'll always get a return from the towers and the blades, and that significantly reduces the energy that gets beyond the turbine to illuminate potential targets. Reflections from targets also need to pass the turbine(s), reducing the return even more. Beamwidths are significant, depending on the antenna configuration. You can have beamwidths of 0.5 degrees and more. That…

Thanks! I wouldn't have guessed the sizes were so large for radar, and just assumed that in current era radar would have progressed to the point of even being able to not send pings at the rotating blades in sync with their rotations (ie always firing radar somewhere within the circle but only at the spots where the blades are not) the same way machine guns fired past propellers on WW2 (or WW1?) fighter planes figured out. But of course a bullet and a radar setup isn't at all the same thing.
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