My grandmother's house is adjacent my parents' w/ 200 ft. between and line of sight. Back in 2013, when my grandmother moved into the then-new house, I setup a point-to-point wifi bridge between them to share my parents' Internet connection and give me easy remote support access to grandma.
Summer of 2023 visiting relatives complained the Internet service in grandma's house was slow and unreliable. There were repeated suggestions made by helpful relatives for purchasing a new WiFi router for her house, getting independent Internet service, etc.
Grandma was happy with it, and the relatives went home, so I put off looking at it. When I did finally look at it, months later (when I went over for Thanksgiving) everything seemed fine.
When the relatives came to visit in summer 2024 they complained again. I looked at it immediately and found massive packet loss on both ends.
The ornamental trees planted along the driveway between the houses were the culprit. With the leaves off (say, at Thanksgiving time) it was fine. When the relatives came to visit in the summer the trees were in full leaf and acting as very good attenuators.
The trees were newly planted when grandma moved in. I didn't even think about them getting bigger and fuller when I set up the link. They filled out in the 10 years intervening, though. (Chalk it up to me still being relatively young and not thinking about installations on 10+ year timescales when I put it up.)
Fortunately there's a room in her house with line of sight to my parents' house unobscured by trees. It meant putting the radio outside a bedroom window instead of the attic (where I'd originally stashed it), but it solved the problem and ended complaints from relatives.
When I took a look at it, it turned out that his (proprietary) wireless USB adapter for the mouse was very close to the band of the noise of the microwave. The microwave was also not properly grounded and shared a circuit breaker with his room, as apparently the kitchen was formerly larger and then split into two rooms by the landlord.
That was quite funny seeing that problem happen in action, he was always joking about a ghost in the machine, and I was joking about him being radiated by his microwave.
The cool part is years later in University one of my commilitones told me that his mouse stops working when the fridge turns on. The first thing that I checked was whether or not there's noise on the power circuit, et voila, easily fixed.
I had to disable a 2.4ghz access point a couple years ago because a bathroom had a passive IR detector for the light switch that would never let the light shutoff. Because detecting IR is a pretty weak signal, I guess these switches amplify it. The issue is the circuit also acts as a weak antenna for 2.4ghz and thinks its seeing IR when it's actually just amplifying and seeing the 2.4ghz beacon signal.
RF gets weird. Something I've thought about over the years is how my FM radios at my old house would sometimes pick up aviation radio which should be AM well above a tuned FM frequency. Apparently this is due to the common design being a superheterodyne receiver which comes with a few quirks (such as causing some small interference itself when it's receiving).
Long ago there was this case of a factory that pressed desks out of steel sheets. Their main press (an absolute monster) had taken someone's arm off and they couldn't find the cause. It turned out that near the roof there was an air conditioning unit that that had a flaky relay in it that drew a gigantic spark on disconnecting, enough to upset the latch that controlled the safety interlock on the press, causing the press to move by itself.
It took quite a while to find it.
- Car allergic to vanilla ice cream: https://www.cs.cmu.edu/~wkw/humour/carproblems.txt
- Can't log in when standing up: https://www.reddit.com/r/talesfromtechsupport/comments/3v52p...
- OpenOffice won't print on Tuesdays: https://bugs.launchpad.net/ubuntu/+source/cupsys/+bug/255161...
This reminds me of a recent issue I had. I had just gotten a new laptop from IT. While picking it up from them, I had generated myself a password, put it in my password manager on my phone, and then entered it twice to set it on the laptop. Everything worked great. But when I got back to my desk, the password didn't work! I tried a bunch of times, watched myself hit each key to eliminate typos, etc.
I went back to IT and they asked me to demonstrate. But this time it worked! I walked back to my desk, thoroughly embarrassed. But a couple hours later I had to log in again and once again could not.
After thinking about it for awhile, I realized that I was typing at IT while standing over a sitting-height desk. Sure enough, typing in that position fixed my issue. I carefully watched what I was doing this time - something about the exact layout of the keyboard and the weird angle I was typing at ensured that I was making a particular typo I typed in that position - just a single letter switched to another, every time. Sure enough, making that one substitution to my intended password got me in.
There’s a video on YouTube about this somewhere and we were able to confirm their findings.
Directional antenas are far from directional, they pick noise from everywhere.
In my opinion rain reduces that noise, and if the point to point has more than enough signal margin to keep operating at full speed, it ends up improving the link.
Something like horse blinders.
Easiest solution: permanently point a good case-fan-sized USB fan on to the unit, using its own USB port.
After hours and hours of iterations I could get it to work perfectly, just once, for each cartridge. I would clean it a bit more, try a game, things would work great. I’d try another game and it the copyright logo would fail. So I’d clean it up a bit more. Swab the port and try it again. It worked! Then another game… nope.
I eventually realized that the isopropanol was making a weak connection work fine, and then I guess it just kept working once power was flowing.
No matter what I tried I couldn’t get it to stay fixed, so I keep a handful of cotton swabs and a small dispenser of isopropanol in the carrying case. I’ll swab a cartridge before inserting it and it works every time.
So now I have a Game Boy that requires alcohol to work.
The fix was easy: Prune the branches. than
>The fix was easy: upgrade our hardware. We replaced our old 802.11g devices with new 802.11n ones, which took advantage of new magic math and physics to make signals more resistant to interference.
I'm surprised WiFi can't pass on reliably through branches. Must have been a nightmare back then.
Update: this comment on the original posting of this article suggests so: https://news.ycombinator.com/item?id=39896699
Discussion then: https://news.ycombinator.com/item?id=39896371
Related:
We can’t send mail farther than 500 miles (2002)
> I wonder how much polarization affects things; I was once told that terrestrial FM Radio is transmitted with vertical polarization to reduce interference from tall objects between you and the transmitter.
> Terrestrial TV (some of which used bands that overlap FM radio) uses horizontal polarization.
This is only true in the US (and probably areas influenced by US standards). In Europe, FM radio transmissions (and digital television nowadays) tend to be mixed-polarization (circular polarization), except if there are known interference (usually border areas) that would preclude mixed-polarization.
Analog television meanwhile significantly differs depending on your area, which required you to either test which tower and polarity is the best (note that all broadcasts are transmitted at a single tower, unlike in the US), or just... request a map with that data.