Interference identification?

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DanubeBCL
Posts: 160
Joined: Sat Jul 02, 2016 12:39 pm

Re: Interference identification?

Postby DanubeBCL » Tue Mar 14, 2017 8:29 am

I suspect harmonics of the charching dock of a lawn mow robot or a photovoltaic inverter.
The harmonics of my eastern neighbour's lawn mowing robot are relatevily stable. Harmonics of TV, monitor power supplies often "wobble". The photovoltaic inverter of a neighbour 80 m away also shows such pulsing. Funny is that the odd and even carriers swap pulsing. It is difficult to 100 % identitfy such an interference without direction finding. There are so many possible sources. But, even when you found the source of the interference it is not guaranteed that you get rid of it. The neighbours normally are stubborn, the national spectrum supervisors do not care and often the noise is within legal limits.

The "photovoltaic" neighbour BTW kicked me out of the house after trying to talk in friendship with him and the authorities cancelled processing before they talked to the neighbour, telling me they had "more important work to do". I should clear the issue with the neighbour myself. The interference is now here for 3 years. No chance to ged rid of it.

And I fully agree with you: Purchasing new equipment like receivers, SDRs or whatever, is totally throwing money out of the window. I once critized the maker of the Elad receivers for doing nothing against PLC interference. After all it spoils his business. He told me that he is a member of a committee against electromagnetic pollution together with other receiver manufacturers. He said word by word: "You cannot imagine how powerful the lobby of the PLC manufacturers is."

PS: I have found the image of the photovoltaic inverter noise which I also showed the spectrum staff (arrows). I marked "Radio 700" because it is important that a radio station is jammed by the noise. Without this premises the staff would not have processed the case at all. The interference is also present in the ham bands. But the authorities were not interested in this at all. They stopped processing the case because of "other, more important appointments".

73, Heinrich
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CaptainNemo
Posts: 114
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Location: Genoa - Italy

Re: Interference identification?

Postby CaptainNemo » Tue Mar 14, 2017 10:23 am

13dka wrote:Well this thread must be jinxed...I enjoyed mostly unharmed reception until this weekend but now... :(
... The only thing I care about is "will it go away?". ...


Did you try to lower the gain? Did you get the same pattern?

DanubeBCL wrote:...the authorities... they had "more important work to do".


In this era of eurosceptic a good new: authorities are the same all over the world... :lol: I feel like home... :D

bye
gio

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DanubeBCL
Posts: 160
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Re: Interference identification?

Postby DanubeBCL » Tue Mar 14, 2017 10:36 am

Well, I really do not want to swing the hammer of Eurosceptics. But European standards have often undermined more practical local standards. E. g. in my PLC example the noise clearly offended the previous German regulations of electromagnetic conformity. But the "harmonised" European law rules now.
And even more evil: The European commissioner who pressed through the first PLC regulations between 2006 and 2009 was a German. :evil: He later worked as a consultant for manufacturers teaching them how to deal with the European Parliament. In other words: He knew how profitable lobbyist work is.
73, Heinrich

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13dka
Posts: 125
Joined: Sun Feb 14, 2016 8:40 am

Re: Interference identification?

Postby 13dka » Wed Mar 15, 2017 7:27 am

The pulses are gone this morning, I just don't know for how long. Trying to locate the source using a portable turned out to be quite a challenge and I failed miserably at it, that the interference consists of pulses didn't make it any easier.

Too bad we don't have anything like class action lawsuits here. If we had those, affected hams, SWLs and the remnants of the industry would at least have a legal ground on which we all could form a network, a lobby against spectrum polluters. Well, some of them. We could file suits for lower emission limits and better enforcement of these limits, albeit with little too no chance to win those. After all, if you look at it a little bit more down-to-earth, for the vast majority of the population it's like, dunno, the steam engine association files a suit for lower minimum speed requirements on the autobahn or lower top speeds on all roads or something. :( And like DanubeBCL already mentioned, PLC is just the tip of the iceberg.

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DanubeBCL
Posts: 160
Joined: Sat Jul 02, 2016 12:39 pm

Re: Interference identification?

Postby DanubeBCL » Wed Mar 15, 2017 10:12 am

13dka, we BCLs and hams do not have the power, influence and money to go into lawsuits. And the outcome of such lawsuits is uncertain. We had some cases in Germany where the filers lost.
And even if you should win a lawsuit against one of your neighbours: When you come home from court three other neighbours in the meantime have installed new jamming devices.
BTW: I am still looking for some quiet place in the country to build a remote receiving station. But this is not so easy. Either the RF noise is already there (even in small villages) or the real estates are unaffordable. I never thought that such efforts would ever be necessary just to listen to the radio. :evil:
73, Heinrich

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CaptainNemo
Posts: 114
Joined: Mon Jan 05, 2015 1:22 pm
Location: Genoa - Italy

Re: Interference identification?

Postby CaptainNemo » Wed Mar 15, 2017 2:45 pm

Anyway, dear friends, let's put it in this way:
chasing unwanted signals is an other new flavor of our hobby ... 8-)

bye

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DanubeBCL
Posts: 160
Joined: Sat Jul 02, 2016 12:39 pm

Re: Interference identification?

Postby DanubeBCL » Wed Mar 15, 2017 4:27 pm

CaptainNemo wrote:chasing unwanted signals is an other new flavor of our hobby ... 8-)
Yes. I already tried the "Worked All PLC" award. But my neighbours did not send QSL cards for my reception reports. :(
73, Heinrich

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13dka
Posts: 125
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Re: Interference identification?

Postby 13dka » Thu Mar 16, 2017 11:46 pm

Heinrich I tried to reply to your PM but it seems you have opted to no receive PMs from other members. Not important though.

The pulses are still gone but I have a new neighbor who obviously got his TV moved into the apartment now, it's "only" narrowband muck every few 100kHz but still - we have 4 (LED-) TVs running in this house and they're all pretty clean RF-wise, but the new guy's old plasma (I guess) tube is really nasty. I know he's staying only for a while so I can ignore that but still.. I wish I'd live alone on an island, with some huge guns to keep neighbors at some distance. :mrgreen:

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DanubeBCL
Posts: 160
Joined: Sat Jul 02, 2016 12:39 pm

Re: Interference identification?

Postby DanubeBCL » Fri Mar 17, 2017 7:46 am

13dka wrote:Heinrich I tried to reply to your PM but it seems you have opted to no receive PMs from other members. Not important though.
Thanks, there seems to be a problem with my email account. But no so important. We cannot do anything against the QRM anyway.
And yes, I know that 100 kHz spaced harmonics of monitors and TV sets. I have lots of them from distances up to 80 m and more. They come in reguarly in the late afternoon one by one when the neighbours switch on their sets. The spacing is between 60 and 100 kHz depending on the frequency their switched PS is operating. But above 5 MHz they totally disappear in the PLC modem noise.
73, Heinrich

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jpsa
Posts: 23
Joined: Sun Nov 06, 2016 10:33 am

Re: Interference identification?

Postby jpsa » Fri Mar 17, 2017 8:31 am

13dka wrote:Well this thread must be jinxed...I enjoyed mostly unharmed reception until this weekend but now... :(

...exact 1 second pulses from 0 to 10 MHz and some dense muck between 2 and 3 MHz...

I see stuff a bit like that too, periodic in both time & frequency, affecting mostly 3 MHz - 5 MHz or thereabouts. It's more like three second intervals, though. I think of it as 'tartan pattern' interference!

Fortunately it's not so strong, and not in a frequency range I try to use much.
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