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Ask Slashdot: Why Does Wireless Gear Degrade Over Time?
acer123 writes "Lately I have replaced several home wireless routers because the signal strength has been found to be degraded. These devices, when new (2+ years ago) would cover an entire house. Over the years, the strength seems to decrease to a point where it might only cover one or two rooms. Of the three that I have replaced for friends, I have not found a common brand, age, etc. It just seems that after time, the signal strength decreases. I know that routers are cheap and easy to replace but I'm curious what actually causes this. I would have assumed that the components would either work or not work; we would either have a full signal or have no signal. I am not an electrical engineer and I can't find the answer online so I'm reaching out to you. Can someone explain how a transmitter can slowly go bad?"
and worn out. Also I think they have pretty short life spans.
As all of your neighbors add wireless routers, the noise floor goes up, and the usable signal goes down, even though the signal strength is the same.
built in failure. bow to your corporate masters and go consume.
Over 3 years I'd imagine a greater density of wifi devices all sharing the same spectrum to have appeared. Perhaps the signal level is the same, but the noise floor has increased substantially, degrading performance.
It could be the noise floor going up near your house, or just planned obsolescence.
..have a tendency to degrade and fail over time.
Obviously the magic smoke, although not released suddenly, does gradually leech out of the components leading to loss of performance over time.
"I bless every day that I continue to live, for every day is pure profit."
Could the analog components of the amplifier/filter circuits be degrading? If capacitors are leaking, etc then that would definitely make the performance decrease but maybe not enough to completely stop working.
You should consider another option: older equipment may not have firmware as good at dealing with congestion (802.11N helps with this), or maybe the new box has 5Ghz which has much less interference issues? Maybe the real degradation was the neighbors installing access points? You may also have had certain pieces of gear installed that interacted badly with your access point (some of them have really awful firmware or very loose implementations of the standard).
These are just guesses... I haven't personally had any degradation except for interference in the 2.4Ghz band. When I bought this house devices would only detect my network and maybe one other. Now seven show up. Interference isn't just a problem in apartments anymore.
Natural != (nontoxic || beneficial)
Probably capacitors degrading, transient spikes making it through the hardware, electrostatic discharge during assembly, just plain overheating as dust coats the internals, more people using the same frequencies (possibly including yourself as you add more wireless devices), and a bevy of other reasons I can't think of at the moment.
This is a hypothesis based on peripheral involvement with analog and digital RF at 0.5 and 1.5 GHz for twenty years.
AFAIK, the output stage of anything broadcasting above about 2 GHz has to be analog, with the lower frequency signal mixed into a carrier at the higher frequency. Digital synthesizers and chips which can deal with 1.5 GHz directly are still very expensive and are unlikely to be used in the consumer routers. So the final output stage is likely an analog RF transistor.
Analog transistors change characteristics with age at elevated temperature, where elevated is anything over 20C. Implanted ions diffuse with time and temperature, changing junction characteristics. The small structures required by high frequencies are more sensitive to such things.
Check the power supply. Usually the electrolytic capacitors are already dry.
Not sure about wireless gear, but some devices (e.g. printers, light bulbs, fridges) are designed to break after a certain period of time, so that you would buy a new one.
Using the same channel does not increase signal interference. Signal interference comes from APs using neighboring channels in close proximity. If you're looking for greater range, try switching to the same channel as your neighbor. Your bandwidth could be lower, but the interference will be reduced.
I've been using wifi instead of ethernet for about 7 years now. Almost all of the NICs/APs I've used have displayed this problem with time. It's as if the equipment somehow develops creeping signal attenuation. My guess is that it's something relating to capacitors gathering a slow overcharge of some sort, causing them to block current in a growing fashion - I seem to recall this being possible from my early days of electronics studies.
Anyhoo, I fix the problem by simply switching the equipment to another channel, say, 3-4 steps away, to make sure the frequency some of the components will be switching at will be notably different. So far it has worked with all equipment I've had this problem show up on. After a while the signal attenuation develops on the new channel as well, upon which I simply switch back to the one I used before. Rinse, repeat.
In my experience power adaptor degradation is the main culprit. Over time the adaptor will provide lower voltages and a less stable current. This translates into a lower signal output and higher noise respectably. I've seen bad adaptor turn repeaters into signal jammers - trust me, that was not an easy issue to troubleshoot...
The loss in performance could be due to the solder between components (mostly between the antenna and circuit board) is degrading overtime (this happen a lot with industrial devices), also the diferents components as capacitor and resistor could be wearing out too.
1. slow burnout of emitter gear due to thermal degradation (yes, clock chips and transistors get hot, as do solder tracks and joints). Thermal runaway can occur if a solder joint fails and arcs, or overvoltage causes signal tracks to vapourise.
2. ionising radiation, particularly on unshielded components such as antenna conductors (I've seen something like this occur on an externally mounted amateur radio antenna: the sunward side of the antenna completely degraded, the result being that the only signals received (or sent) were on the shadow side).
3. component quality on consumer gear is not as stringent as it could be. Components can and do fail, and considering the number of components in a lot of consumer gear, it's a wonder any of it actually leaves the factory.
4. the noise floor of several years ago was far, far lower than it is now. The ERP of newer gear is (by design or by necessity) higher than older gear as more and more transmitters have to share the band. As a result, the signal quality taking a dive may be at least partly illusory. The equipment may actually be perfectly fine.
5. parasitic structures in semiconductor packages may be the catalyst for failure, either immediate or delayed. Such structures may be as small as a single atom of chlorine embedded in a crystal of germanium - innocuous at first (undetectable, even), but over time and use, that contamination will alter the chemistry of the semiconductor, possibly causing it to bond with the package material and rendering it useless. This might not even be an issue in high powered gear like regulators but in something like a microprocessor, it's a showstopper.
Operation Guillotine is in effect.
Tell their stinkin' signals to get off your lawn!
Table-ized A.I.
Tell their stinkin' signals to get off your lawn!
Lawn, hell! They've gotten into his house...
Those who can make you believe absurdities can make you commit atrocities. - Voltaire
Eating away at the PCB!
Perhaps it's frequency drift. As components age their values change slightly. And when dealing with 2.4 Ghz and above tolerances are strict. It's just my guess.. Take it or leave it.
Using the same channel does not increase signal interference. Signal interference comes from APs using neighboring channels in close proximity.
Err, that makes zero sense. Wifi access points do not coordinate their transmissions or do any sort of code division multiplexing or anything else that might help with interference. Two transmitters on the same channel will absolutely interfere, worse than if they were on neighbouring channels. If you are lucky, they will interfere enough that the other access point decides to switch channel.
Finally! A year of moderation! Ready for 2019?
The poor ministrations of the duties of the tech priests leads to decay. It's either that or it's been touched by Nurgle.
Like, oh, say, "smart meters".
When they started installing "smart meters" in my area because "too many" people were installing solar, and PGE were paniced that they'd have to pay the same rate they were charging instead of cutting off the payout at net zero by having differential rates so they payed less when solar was active, my bandwidth went to hell, and I had to more centrally locate my AP to avoid the interference.
I haven't been to an Applied Superconductivity Conference for a decade, but at that time people were beginning to sell racks of very narrow band receivers for cell systems with high temperature superconductors allowing a narrower bandwidth than anything one can do at room temperature. Sterling refrigerators at 80K. One was able to increase channel density about a factor of three. I don't think this technology has made it to consumer electronics yet. Or will.
and nobody asked:
âoeDid you measure the signal quality?â
There are lots of apps that show you various signal parameters for most platforms (Linux, iOS, Windows). Even if you donâ(TM)t know what the signal parameters mean, the magnitude of difference between an old and new router can tell you something.
I think, if there is no difference, it is perception based; otherwise an overworked flux capacitor.
Go get some Apple AirPort Expresses. :)
Note: I'm an Apple fanboy and heavily invested.
I've tried DLink, Linksys, Cisco [which works, but on the $$$ corporate level], a few others, and Zyxel. Zyxel came close -- but the configuration has to be specific [repeater talk to SSID w/ specific MAC id]. The default quick setup could leave the sub-routers chattering amongst themselves... But I digress.
The AirPort's at $99 pay for themselves in setup alone. And frankly, they "just work". Unlike all the others the AirPort DOES PROPERLY PASS ALONG MULTI-CAST THROUGHOUT THE NETWORK. All the other products sub-routers ... dropped multi-cast. No more AirPrint, AirVideo, etc... Yeah -- there's a ton of iOS devices along with Mac's involved on my networks now. :)
They dynamically can be setup as a sub-sub-repeater. Wander the network rather seamlessly. I've just recently gone through this headache and with the AirPort's they will *OWN* the area I want to cover -- add AirPort's as needed to have signal strength / coverage. Just did a 6,000sq/ft house -- all three floors, my home, and the office at 18,000 sq/ft plus yard coverage [as the bay doors are opened :-].
Amazing product.
Too stupid? Actually most people aren't 'stupid', it's just that most of the population don't live and breathe IT issues. An equally narrow-minded, self-absorbed mom in a typical household would also think you're stupid because you can't cook as well as she can.
When you grow up and leave your parent's basement, here's a tip -- try to be more diplomatic and really try to understand society as a whole. Not everyone knows what you do and conversely you're not stupid because you don't have the various skill-sets of everyone around you. Some day soon you'll be out in the job market and when that happens you won't score points in any job interview by stating how everyone else is stupid because you know something like how to change channels on your wireless router and they don't.
It isn't just their cheap stuff. One of my Cisco 877s started randomly rebooting.
The two large caps on the board were faulty, so I replaced them and now it works perfectly.
Monster Cables(tm) are much better for carrying electric audio signals, because they are outrageously expensive.
You need to buy cans of Monster Air to spray around your house.
You can find the product on their web site, and you really will be able to hear the difference on your wireless connections.
Probably.
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
They'll swap brand parts for something their brother, cousin, whatever makes for a fraction of the cost, bugger the value tolerances or the longevity of the substituted components. Then in that tiny, unobtrusive case, the crappy parts cook, degrade and eventually blow up if you haven't replaced the whole device in the meantime.
Remember the problems with the first batch of Raspberry Pi's? The manufacturing samples came back all to spec and with the correct components and the contractor was given the go-ahead to produce the first batch. First thing they did was to switch the ethernet socket with magnetics for a cheaper one without magnetics. Passed the static check on the production line fine, arrived back in the UK and failed when actually required to work in a live situation. Luckily, the Foundation had access to some non-destructive investigation equipment and x-ray examination of the ethernet socket revealed the lack of those pesky little ferrite cores.
If that happens to a small outfit with its finger on the piulse, then I suppose the scope for sharp practice is greater with large companies and their long production runs and more remote quality testing.
"Bingo, I would wager that most households use wireless only now, since wireless only devices are becoming so popular. I just bought a house...not one inch of ethernet in the place. I don't know about you guys...but that would drive me crazy to make all my desktops wireless!"
Same here. My house was built in the 1950s. Guess they used mostly wifi back then, too.
Some idiot thought it was cheaper to spend $1 less on caps than the cost for customers calling tech support repeatedly for flakey performance.
A lot of tech companies have bean counters in charge, except they don't even know much about beans.
“Common sense is not so common.” — Voltaire
False. There are provisions for just such a thing.
Maybe we should be bitching that this is not turned on by default?
Beyond that: The signal is spread-spectrum. It is resistant to interference because of this. Depending which 802.11 you are using, you may also be frequency-hopping. As well, each channel is not just a notch of spectra. There's an attenuation mask they are supposed to follow as well.
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
Six years ago, I took some tupperware cereal containers, drilled two holes in the bottom and pushed a WRT54G router's twin antennae through each hole. I caulked both holes. I inverted the containers, took an old broom stick and jammed it up into the contaners and screwed each router up high outdoors on buildings spaced 400' apart. I configured all three routers with DD-WRT in bridged/AP mode. I have never taken them down. This is in Vermont. They work great and cover some 18 acres. What more can I say?
*** Don't be dull.***
I'm glad this question was asked, because I've experienced the same thing in many situations. (When I worked doing on-site PC service, I had a lot of service calls related to wi-fi issues, and often found routers in a degraded state. One was so bad, you could literally only see the SSID and make a connection if you had a laptop or mobile device within 2-3 feet of it!)
The explanation about bad capacitors sounds about right though, since that's been the bane of most other modern electronics over the last decade or so. If not capacitors, I imagine other inferior quality parts soldered onto the circuit board that fail with heat and time.
As cheap as some of the wireless routers have become though, I suppose they really are pretty disposable. I've got a Tenda branded Chinese wireless N router here that's actually working pretty well for me with a 50mbit cable modem connection from Comcast attached to it. I have a 3 story townhouse apt. and the signal is still pretty good on the 3rd. floor with this down in the corner of the basement. The router's cost? Absolutely free last year with a coupon Micro Center mailed out. But I can buy them there all day long for about $20 each.
I just replied with that suggestion while I was reading through, I should have read farther... my only router problem was caused by a bad PSU... it was only outputing 3.2V when it should have been putting out 9. I replaced it with a universal wall-wart PS, and it works just fine again. Considering that I doubt it just all of a sudden went from 9 to 3.2V, I would guess my wireless was getting worse and worse (although most of my stuff is wired, so I wouldn't have noticed).
Stupid sexy Flanders.
Old Bathroom cabinets (1950s) have a slit to dispose of razor blades by throwing them down the wall.
While this was o.k. to do in the 1950s, the inside walls of your house slowly filling up with razor blades will degrade the wireless signal. To make matters worse, blades were specifically designed to be lambda/4 of 2.4Ghz. Two touching razor blades that are sufficiently dirty and corroded will create a simple crystal receiver and rebroadcast your wireless signal with a random frequency shift. (The original intention of course was to disrupt Russian radar.) /p
To make matters worse, having two or more bathrooms might create a phase shifting device that could concentrate your and your neighbors' microwave radiation at random spots in your house or yard. My only advice is, never to stay at one spot too long, as this has been linked to spontaneous human combustion.
Having worked on some of the 802.11 algorithms, I can safely predict that all equipment with a crystal oscillator will eventually degrade.
802.11g was speced for a differential frequency deviation of 40ppm. Nominally thats 20 ppm allocated to AP and 20 to the remote.
In an effort to cut costs as much as possible (because most of you shop only on price, right?), the crystals used do not have good aging properties. It's not unusual to see crystals used that have as much as a 5-10ppm/yr agiing spec.
Unluckly customers will see their AP and remote device diverge, and within 3-4 years the frequencies are out of range of the algorithm's ability to compensate.
Actually, that's not true. In this case, excess cooling is the most likely cause. Just like your, you know, when you have a cold shower, the antenna chip shrivels slightly and doesn't want to perform.
It's an exploit of a loophole in /. moderation. Funny mods provide no 'karma'. The basic idea is mod the post up funny, and back down overrated. This can repeat without end with enough moderators, and the poster goes to full negative karma for just one post.
Low quality capacitors are known to go to crap rather quickly. As the capacitors die the filter circuits will "spread" the range of frequencies that will be accepted as valid signal. Timers dependent on capacitive charge will also get "slower" (e.g. take longer to reach the charging threshold and rigger the time event).
The sad truth is that modern electronics, particularly those built on the cheap or with poorly sourced components, just go stale on the shelf, and go stale faster when in use.
Innocent people shouldn't be forced to pay for inferior software development.
--"Code Complete" Microsoft Press
Almost all cheap and even some expensive router's are built to fail. Cheap components and no cooling end up causing weak BGA joints and dryedup cap's causing it to fail. It the same with new TV's they last a few years then they die because of bad caps or overheated voltage regulators. look at old tv's they go forever. well until the tube burns out. I have a old console TV still works.
Over the years I've owned modem/routers by Netgear, Linksys, Cisco, Swann, TP-Link, Thomson, Corega, Origo, D-Link, probably some others too. I've used them with different ISP in different countries, various physical locations, in the presence and absence of other local networks, with stock or custom firmware (DD-WRT, Tomato and OpenWRT) and I've come to one conclusion: they're all crap.
For the most part they work ok when new, but I have never had a router that stayed working for more than a couple of years. Usually the first symptom is wifi dropouts, then dropping ADSL, then router crashes. Eventually they just stop responding at all. It's not interference since getting a new router always fixes it all (for a bit anyway). I really don't understand how they would 'wear out' (being solid state); perhaps poor thermal design? I'm not a demanding user - they need to connect my ADSL to my ethernet and wifi quickly and reliably and provide NAT, DHCP, basic firewalling, operation as a DHCP relay or bridged access point if it's not a modem; I can happily do without media servers, port triggers, QoS, static routes, print serving etc - if it can't provide my most basic requirement of simply maintaining a connection, all that's just excess junk.
I've had the worst record with Netgear; their stuff just likes to die. I've not tried Apple, Buffalo or Draytek. Most of the open firmware is generally better than stock, but instability and risk of 'bricking' is stupidly high, and we wouldn't need them if stock firmware was decent in the first place.
It all seems a bit like my experience with Terry Pratchett books - I have a bad experience with one, so I look for suggestions, get recommended something, try that, and and am disappointed yet again. I'm certain there must be a market for wifi kit that isn't crap; it seems to be up for grabs.
Most people on slashdot are fixated on one answer. It could be any of them.
1. Bad hardware including AC adapters, poor caps, bad cooling, etc.
2. Interference from neighbor's devices, this doesn't just have to be wifi access points. Had a neighbor who was into building tesla coils. It totally screwed up my wifi when he was playing with it.
3. Poor drivers or wifi devices in your computer. Had a linksys card die on me. It wouldn't stay connected more than a few minutes at a time (pc card)
4. All your neighbors caught up to your wifi router's capabilities. Cheap 802.11n devices are available now.
I moved into a new house and everyone in the neighborhood had linksys routers operating on 802.11g. There was so much interference all around me that I couldn't get a connection upstairs and two concurrent computers could never stay connected. I upgraded to an 802.11n apple airport extreme. It can operate at 2.4 and 5Ghz and now I'm the dick in the neighborhood that overwhelms everyone else's wifi signal because I spent more than $50 on a router. Two years later, I only see one device that's on 802.11n besides mine.
At this point, I just gave up on wifi for serious tasks and use powerline networking. It's much faster although I've noticed some CFLs cause interference with it so I've had to go to LED light bulbs.
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