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Intermittent Powerline Dropout

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I second the huge THANK YOU to snagro for the 'constant ping' suggestion, like SansB I have been running without dropouts now for two days - though in my case I am simply pinging the router from my machine rather than pinging an external website. Don't think the problem has anything to do with power-saving on the adapters as the Devolo ones allow you to disable power-saving on each adapter (which made no difference).
 
Devolo support confirmed their adapters use a QCA chipset, so more weight behind the argument that its a problem restricted to QCA devices. They have also asked that I place a network switch between the adapter and the PC - no idea what that is meant to prove - anyone?
 
Can you drape a CAT5e wire just to make sure it is not happening on the wire side? You know when it is going to happen so just lay out a patch cable right before to make sure. Probably is the power adapter but maybe something with the Ethernet port.
 
My guess is there could be QRN caused by all kinds of appliances cycling on/off within the household as well as from the neighborhood. Hang the scope on the power line and observe how much noise is floating around. Most likely AM type random noise that is.
 
Can you drape a CAT5e wire just to make sure it is not happening on the wire side? You know when it is going to happen so just lay out a patch cable right before to make sure. Probably is the power adapter but maybe something with the Ethernet port.
When you say "maybe something with the ethernet port" do you mean the port on the PC, the port on the router, or the port on the adapter? Unlikely as all have been swapped out during troubleshooting. The only element that hasn't been changed is the mains wiring. Have thought of running a cat5 cable to the PC but impractical as office and router are at opposite ends of the apartment. p.s. why do you say "you know when it's going to happen"? The dropouts are random.
 
My guess is there could be QRN caused by all kinds of appliances cycling on/off within the household as well as from the neighborhood. Hang the scope on the power line and observe how much noise is floating around. Most likely AM type random noise that is.

Maybe so, but why does the constant ping to the router over the same connection solve the problem? Surely the interference, if there is any, would slow down or stop the ping as well? It doesn't.
 
When you say "maybe something with the ethernet port" do you mean the port on the PC, the port on the router, or the port on the adapter? Unlikely as all have been swapped out during troubleshooting. The only element that hasn't been changed is the mains wiring. Have thought of running a cat5 cable to the PC but impractical as office and router are at opposite ends of the apartment. p.s. why do you say "you know when it's going to happen"? The dropouts are random.

I have seen Ethernet ports go into power saving mode with problems. Not all Ethernet ports support the same level of firmware. Sometimes some Ethernet ports just don't like to adjust to other Ethernet ports so you have interaction problems. It is just a test for a complete picture. Adding the switch is another way to test this.
 
Maybe so, but why does the constant ping to the router over the same connection solve the problem? Surely the interference, if there is any, would slow down or stop the ping as well? It doesn't.

That is kinda possible with some smart technology including software to go with it. So called noise blanking is used in modern radios.(Modern radios are more software than hardware these days with updatable f/w, etc.) repeated ping can learn the noise pattern and deal with it. I am just guessing here.
 
Maybe so, but why does the constant ping to the router over the same connection solve the problem? Surely the interference, if there is any, would slow down or stop the ping as well? It doesn't

Seem's more like the HomePlugs are getting out of sync, or one is going into Sleep mode...

As far as interference on the PHY - remember that HPAV is Windowed OFDM, and does map it's way around noise - what's interesting is that each window can have a different modulation scheme within the band... and they notch around most common SW/MW radio bands (to keep the HAM's happy)...

Old-school dimmer switches - dimmers that use phase-cut, these can generate a huge amount of noise on the loop, so watch for them. Quick test here - turn off the lights that are controlled by dimmers...

HPAV_Noise_Sources.png


Switching power supplies - e.g. cell phone chargers - some are pretty cheap, and can generate more noise on the loop if not properly isolated between the high voltage side and the low-voltage DC side - and the frequency that it switches at, this can cause problems inside the frequency bands that HPAV uses - quick test here - unplug the chargers and see what happens

Other things - mixing HomePlug 1.0 and HomePlugAV adapters - they're supposed to be compatible, but consider that HP 1.0 has different error correction and OFDM sub-carrier schemes, it's not wise to mix them up...

HPAV_PHY.png

Lastly - try changing the name of the HomePlug sets, getting away from the defaults... and double check the QoS schemes on each HP adapter - whether it's Internet, Voice, Video, or Gaming, getting these out of sync can cause timing issues that make the adapters lose sync...

Hope this helps...
 
Thanks all for comprehensive suggestions. I have ruled out the ethernet ports as the source of problems since I have had the same issue despite having swapped out (a) the HomePlug adaptor set (b) the pc and (c) the router independently during troubleshooting. "Homeplugs getting out of sync or going into sleep mode" is possible but unlikely as same thing has happened with two different manufacturers sets, and the current Devolo plugs indicate when they are in power saving mode (LED on adaptor blinking instead of solid). As we have no dimmers, the HomePlugs do not have their default names, and are of identical specifications, I guess that just leaves the chargers, and the QoS schemes - absolutely no idea how to check the latter - unplugging the chargers I can manage!
 
Well, FWIW, trolling the google - not looking for flame-bait, but in the catching fish in a boat context - seems like more complaints for HP/HPav do seem to be focused on the QC-Atheros solutions - but I'm not certain if that's an issue, as they've had a reasonable amount of success at shipping solutions - more devices/more complaints...

;)
 
Not that I'm able to add much to some of the technical discussions above, I'd just like to report that the constant ping across the Homeplugs is continuing to work with no loss in connectivity. The constant ping has now been going on for 3 weeks, and we haven't had a single outage. They are working exactly as well as I had hoped when I purchased them.

Prior to the ping solution I had pretty effectively eliminated all plug-in sources of noise by putting all appliances, electronics, and anything else that plugs in to the mains on noise filtering surge protectors, while the Homeplugs were the only devices directly plugged in to the wall. This did a lot to improve overall performance and reduced the intermittent dropouts, but didn't eliminate it completely.

The only major source of noise that I couldn't do anything about was the heat pump/AC unit which is directly wired into the mains. I was previously convinced this was the cause of the dropouts. However, the past two weeks the weather has been all over the place, with the heat and AC turning on at different times of the day, yet with the ping we haven't had any problems.

The Homeplugs are using a custom network name, and the QoS settings match on each device. Unfortunately Netgear doesn't provide a lot of options to tweaking any other settings or options (and actually the PLP1200s don't even have an official management utility and I had to use an older utility to set the Network Name).

Whatever the issue is, it does appear specific to QCA chipsets. Like I said in my previous post, I have three different generations of adapters (AV500, AV2 SISO, AV2 MIMO) that all have QCA chipsets. All three pairs have the same problem. I'm thinking about testing the older adapter pairs in turn with the ping to see if it fixes them as well.

I've also been toying with the idea of getting a pair of Extollo LANSocket 1500s, since they are Broadcom based just to compare. However, considering I had almost given up on Homeplugs and the PLP1200s are now working perfectly, I don't know if I can justify the cost for an unknown. :\
 
Devolo have responded to my issue log by suggesting I use a 10m ethernet cable from adapter to PC, which they supplied, but it made no difference. They then sent me some 'modified' adapters (not sure what had been modified) and still no change. As per SansB the only thing which has consistently eliminated the dropouts is the constant ping to the router.
 
TP-Link dropped a firmware update (dated March 2016) that seems to help out quite a bit for the AV1200 TL-PA08030P devices... dropouts went to zero in my case - been running it for about a week now..

check their support site for details.
 
My ZyXEL PLA5206 has been going rock solid since January. Not a single dropout that I have noticed.

I'm still inclined to believe this is an issue based on Qualcomm chip-set. Can one of the folks with this problem try out a set with Broadcom. If it doesn't solve the problem return your product?
 
TP-Link dropped a firmware update (dated March 2016) that seems to help out quite a bit for the AV1200 TL-PA08030P devices... dropouts went to zero in my case - been running it for about a week now..

check their support site for details.
That's good to hear but I would like to see fixes for all the previous generations of TP-Link adapters which suffer from the same dropouts.
 
Realise this is an old thread but just wondering if the Broadcom/Qualcomm theory has been confirmed or disproved, or if anyone has found a better solution than the 'constant ping' (which is still working)
 
Realise this is an old thread but just wondering if the Broadcom/Qualcomm theory has been confirmed or disproved, or if anyone has found a better solution than the 'constant ping' (which is still working)

No, but the new Broadcom based TPLink AV2000s have worked rock solid for me, for weeks. However, switched to MoCA now. I only got about 70 Mbps, really wanted the full 110 Mbps out of my DSL.
 
Just discovered the Devolo units I have been having problems with have a Broadcom chipset, so another theory bites the dust. Reluctant to change to TP-Link as Devolo support have been super helpful, but will give them a try.
 
Which Devolo's ? The Devolo dLAN 1200+ is not Broadcom, it is also the QCA 7500. In my experience, these suffer from the same random dropouts as e.g. the TPlink TL-PA8010 or PA8030.

Tp-Links TL-PA9020 uses the BCM60500. The promised 2 Gbps is clearly non sense. I have link speeds close to 800-900 Mpbs. The actual ethernet speed is much lower. However, in my home they were robust against all the bad things coming from supplies, chargers and more. Never saw a dropout in 3-4 weeks.

There are theories where the dropouts come from, like sleep modes and sending an occasional ping might keep the connection alive.
 

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