RFLink and sudden range drop

[Nautilus]

Hi,

I know this is probably not directly linked to Domoticz but as there are probably many people here using RFLink with Domoticz I thought I'd ask if there are any who have experienced what I just did. And if you have, did you find some root cause or good troubleshooting methods.

My issue was that RFLink (latest official firmware) has been working very stable and it has a good range with external antenna. But suddenly on last Saturday evening it first looked liked it had stopped working - although a bit later I concluded that just the range had dramatically dropped. I wasn't even at home at that time so I first really noticed it on Sunday morning when my Nexa swtiches didn't work. A couple of them, closer to the RFLink's antenna still worked. I then checked 433Mhz thermometers and they had stopped updating on Saturday evening around 10PM.

I then stopped the RFLink hardware and restarted, then rebooted the Raspberry Pi to which it is connected, and finally tested also with another antenna and different antenna positioning. All this had no or little effect on the range. At this point I started thinking it has just died as it is few years old already. I was away from home most of the remaining day and to my surprise when I came back it was again working as it used to.

But now I'm left puzzled that what just happened. Why the range dropped, why it came back? If this happens again, is there something I can do to fix it quicker?

Thanks in advance for any insights you might have on this...

[bjornhallberg]

Any updates on this? I've also experienced a substantial range drop some time in the last months. I didn't discover it until I plugged in my remote 433MHz sockets for the xmas lights and saw very erratic operation and range. I used to get signals from across the block, now I struggle to turn on a relay from two meters away.

I have both the RFLINK official transceiver as well as a cobbled together version with separate transmitter and receiver. Both function just as badly. Tried another power plug for the Raspberry with no change. Running Domoticz v4.10629. Will update to the latest beta to see if it helps.

[DutchHans]

Strange... I have an rfxcom and also noticed a rangedrop... Switches that worked for years are suddenly not or bad responding... Could it be related?..

Hans

[Nautilus]

Mine's been now stable again for about a week (since last Sunday). I did not update Domoticz at that time, only rebooted. That did not have any immediate effect. I'm currently running 4.11551 (Compile Date: 2019-12-05 12:00:48). Could it have been some sort of electromagnetic interference...

[bjornhallberg]

Still no improvement here, and the problem is not related to RFLink at all it seems. I tried switching the remote relay sockets (several brands / models) using the supplied remote (also several different remotes) and got a range of about 10 cm (!) maximum. What could cause this? To my recollection I have not plugged in anything new to the electrical grid lately. It would have to be an old appliance going bad or the neighbors connecting something really evil.

[sancla]

Could it be interference?
Any chance you can get you hands on a SDR (Software Defined Radio) ? That would at least give you some insights in what is going on in the ether...

And how about linking the RFLink to your own computer?

Sent from mobile phone

[bjornhallberg]

Thought about setting up some sort of SDR. Any recommendations? Looking at RTL-SDR or NESDR currently.

[sancla]

Personally I once bought this one from AliExpress without any regrets:
€ 19,08 | RTL2832U + R820T2 100 Khz-1.7 Ghz Uhf Vhf Hf Rtl. Sdr Usb Tuner Ontvanger Am Fm Radio
https://a.aliexpress.com/svuhRCmMF

They are cheap, dirty and enough for me to gain some insights. But not that very accurate, especially in the higher and lower bands. But they are a lot of fun!
Should you live near the Belgium/Dutch border I can bring it to you...

I am thinking for some time to buy an Hack RF, but as it's different price category I need to think a bit longer about that one until I have some budget for it (to many projects, wishes, likes, wanahaves etc ...). Cool thing about the Hack RF is that is can also transmit instead of only receiving!

Another solution could be to use a DVB-T (digital television) receiver and use that as an dirty and even cheaper SDR. Their are multiple sources to be found on the internet on that subject...

After all, you are more looking for a way to find the source of the interference, not any exact precision measurements. A cheap SDR could be enough for that. It's up to your budget and how fast you want it to find the best solution...

Sent from mobile phone

[Dave21w]

Sounds very much like interference, most cheap 433Mhz devices have no form of battery mangement, some just stop working and others go into a strange locked up state where they contantly transmit garbage until the battery finally dies, a prime example of this is the Kerui D026 door sensor, I had one of these on my back door and experienced lots of devices dropping off my 433Mhz network, it wasn't until I noticed the little red light on it flashing away contantly at about 5Hz that I realised what had happened, this was one of the reasons that all my door sensors are now zigbee devices.

Given the amount of cheap weather stations out there that use the same frequency it doesn't have to be one of your devices thats causing the problem, could well be a neighbour !!