Weather Station Hardware > Blitzortung

Interference and Noise

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Phil23:
Just browsed this entire thread & I see no mention of the Digital Filter Option.

I'd be interested to hear more about it & see the interface options available when it's installed.
I did see mention of "Above 20kHz....

A look at the data sheets indicates the devices can filter lower.
It mentions 128kHz/32kHz/8kHz.

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In my case I'm looking at a source that's in the 18-20kHz range that's permanently there & a bit directional.

It may well be just part of my environment which has stuff like a Ubiquiti PowerBeam 5AC, fed by PoE.
14 security cameras also on Poe.
Hybrid Solar inverter & panels.

All in about 300m of CAT6 running about the place & a total of 5 network switches.

Considering moving my station to the rear of the property, about a 20m displacement, but that will not change it's location much in relation to an extension lead that runs on the other side of the yard to get power & data to the other shed via Ethernet Over Power adaptors.

Edit,

I'm Station 1928 by the way.

Cutty Sark Sailor:
Sorry... if you have interferers below 20 KHz, those are junk you'll have to find physical or channel gain/threshold solutions.  I've three systems, 2 Reds, and a 19.1  BLUE developer's release with repairs and modifications. I can tell you from experience there are simply some things we have to learn to live with, and adjust to... If your station must operate at a maximum range of 800 km because of your 18 K noise... so be it.. the informatuion you send will be just as viable, and likely of better quality for those signals, as folks in excellent locations, who can run 4000miles.   So What????  You probaably can't be a locator beyond 800 miles normally anyway.... sure you miss some 'detectons', but you'll send a lot less useless signals.  30-800 km is one of the original network paradigms, anyway... best data, least junk signals,etc. 

The primary impulse charactistics we'rei interested in is the 3 kHz to 30 kHz range. Higher frequencies are important, so the more that are present, the better data. The design bandpass of a System Blue is 3-300+ KHz with the HP filter analog secment operating. With it off, the BP is 3-60 KHz.

The optional filters, if installed, are operating currently at a LP variable of 22 toi 220 KHz.  Neither your 'normal' "HP off" even with optional filter combinations, will eliminate signals below 20khz.  Additionally, since the Server computation algorithms for computation of vall the various filter configuratio9ns oif the optional filters are still in development, use of the optional filkters in some circumstances can lead to degradation in data quality.
When first released, those optional filters were allowed to run wide open, about 5  to 300+. What was discovered at frequemcies above 250 KHz, digital artifacts and distortion would be at times introduced into the digital portion, among these digital aliasing, at the preferred sampling rate of 500kHz...

The system can function, of course, at a higher sampling rate, but so many operators "played games" with things they may not be conversant with,  the Server was told to 'disregard any signals not at 500, and  all the systems were sent configuration commands from the server to restrict the optional filters to 20-220 kHz.   That's where it still remains, until all the 'experimental' amd developmental algorithms, both for filter settings, higher samoling freq, higher signal rate, a DSP filter, noise elimination are incorporated on ZSserver, and in system firmware as applicable

Phil23:
My interference is definitely emanating from the Solar Panels.

Rotated my loop today & it was apparent in the change & noise floor on the suspect channels went down.
Dragged the H-Field & E-Probe down from the roof & tied them to a steel post in the back yard & all much better.
About a 10m displacement.

Plan B is to get it on the far Gable of the garage. Got a new switch for in there today & a data cabinet up,
so should go on plan for a proper relocation next weekend.

miraculon:

--- Quote from: Phil23 on September 02, 2019, 06:07:51 AM ---My interference is definitely emanating from the Solar Panels.

Rotated my loop today & it was apparent in the change & noise floor on the suspect channels went down.
Dragged the H-Field & E-Probe down from the roof & tied them to a steel post in the back yard & all much better.
About a 10m displacement.

Plan B is to get it on the far Gable of the garage. Got a new switch for in there today & a data cab up,
so should go on plan for a proper relocation next weekend.

--- End quote ---

I am a Ham Radio operator and subscribe to the QST magazine. A few years back there was an article about noise from solar panels and interference on Ham radio bands.

The RSGB has the article available here: https://rsgb.org/main/files/2014/02/QST20Solar20April2020165b25d.pdf

Perhaps you might find some useful advice in the article. Even though the HF Ham bands are not particularly high frequency, you may need to adapt some of the advice for lower frequencies that the Blitzortung system is looking for. Relocating the antenna farther away is a good step, I agree.

Greg H.

W0BTU:
Thank you for sharing this. The article talks about reducing interference in the HF bands using ferrite.

However, mix 26 powdered-iron is much better suited for ELF than any ferrite mix. Details at https://ham.stackexchange.com/questions/10003/need-a-ferrite-suppression-material-for-choking-15-khz-to-60-khz .

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