Author Topic: Reducing Interference Mode  (Read 472 times)

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Offline eidsness

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Reducing Interference Mode
« on: August 23, 2019, 09:42:57 PM »
I'm a new staiton operator (2559) and am looking for ways to reduce the time I spend in interference mode.  I notice that my station is sometimes near the top of the list for my region (Canada), but it often drops quite a ways lower.  I think this means that I have a fairly good location, but am being affected by periodic interference.

Over email with Dale Z. I was pointed to this forum.  I've reviewed the pinned thread here on interference, but haven't been able to understand alot of the important parts.  I think that i have two basic questions:

1) Dale's build summary (https://www.bismarckweather.net/Temp/Blitzortung_Build.pdf) has great detail on several aspects.  From that article and from direct email he has described that shielding the ferrite antennas would be a big help.  In that article he used copper tape over pipe for the shielding.  I have some silver metal tape (probably Al, but I'm not sure), but no copper tape.  I'm wondering if people think that a copper pipe would be effective instead?  I would cut a slit down one side and fill it with thin wood or plastic to keep the gap open, then slide the antenna in the middle.  Is using copper important to this shielding, or would my existing metal-foil tape work as well as copper?

2) Also, I'm wondering about construction of the e-probe.  From some article (I no longer have the link) I was targeting a 5mm2 wire, approx 10cm long.  What I found was 10 gauge (approx 5.5 mm2) and I cut it a bit long, but then bent the end to get 10cm.  Since then (from Dale Z. and other places) I've learned that 16 gauge (1.5 mm2) is a better choice.  How much of an effect does the size of the e-probe have on performance?

Thanks for any advice.

Offline Cutty Sark Sailor

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Re: Reducing Interference Mode
« Reply #1 on: August 24, 2019, 10:50:57 AM »

I have a very noisy EM Environment. Optimizing takes time. My environment is variable.
Thursday I think it was I had a completely new interferer which kept me reduced or in interferece most of the day, on all three systems 689, 791, 1439.  Near Field Magnetic and Electrical. Never did chase it down... then it vanished sometime overnight.  We have to live with such situations, and adapt and optimize as best we can.
 
Shielding ferrites of no use for magnetic interference. Some effect for electrical. Watching your signals for a bit, I suggest shielding would be a waste of time for you.
 
I have 3 different types of E probes. It is not so much the 'size' of the probe, it's the height above earth, and isolation from structures, trees, etc. The 'surface area' (size) is important, but 'bigger' isn't necessarily 'better'.  The assembly is EXTREMELY sensitive to charge state, and in fact operates with a LOSS as far as 'power' into the Controller amps. The E field  assembly, including the Coax, is NOT an antenna.. It mirrors the electric charge state of the Earth / Atmoshere 'capacitor'.
See  https://forum.blitzortung.org/showthread.php?tid=2749  for a quick look at 'propagation / detection".
my three stations, respectively, (in mm) 350*2 - 150*3 - and 250*4 ---but all are 21 feet above earth, no significant difference in performance, though the gain settings vary for the E channels.


For H field, I Use a modified Ferrite build, 300*7.5 core, finding these the very best size and option for many reasons, in my situation. Here's a link to the V1 version.  50mb PDF: https://sferics.us/misc/CSS%20Thingie%201b.pdf  I currently use a Version 2, which I won't describe presently.

This project is not about 'competition' to be on top of list, though that is a great ego kick,.. it's not about 'detecting' strokes. It's about LOCATING strokes accurately, and for that goal, generally only about 17 stations within the region will actually be used... the BEST data channel from those.  Everybody else's Involved Data classes them as 'detector's....  You are computed on Region 3 Server (Amerucas) so your data within region selection should be 'North America) though Canada 'sort' is possible.

I'm workwing on a page which shows how your signals are computed. It's still very much draft. but it may help.
https://sferics.us/resource/SignalEval.html

You're running 'automatic' mode. This will drive your gains up and down. Suggest full manual, no automatics at all.
You'll chase your own tail trying to optimize in automatic.

You're apparently using stock 200mm ferrites. You need to add on your configuration data on BT the diameter, which I think is 8mm.
On that same page,a the antenna config should be HA=0, HB=1 HC=2 (undefined if not used), E ALWAYS on 3, 4-5 undefined for sys BLUE

Set all Thresholds (triggers) at 100mv and apply/save.
Set all gains at 10*10 HP ON.
Disable H Channel C, since your'e Not using it.

Gain settings affect the Analog Chain.
Threshold is a digital function. 100mv is the 'sdtandard' base which 'Effective Gains' are computed. Try to leave this at 100.

More Info on setup here (must be logged in and have operator membership)
https://forum.blitzortung.org/showthread.php?tid=2573&pid=18216&highlight=manual+mode#pid18216

Have Fun

Mike
 

Offline eidsness

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Re: Reducing Interference Mode
« Reply #2 on: August 24, 2019, 03:46:14 PM »
Thanks for the detail reply.

My e-probe is mounted on my roof, which is as high as I can put it.  Our place is surrounded by trees that are much taller than the house.  I can't do anything about them, however that is the only obstruction.  We're in a subdivision and all buildings are approximately the same height.

My e-probe is a length of 10 gauge copper pipe, which goes directly into the pre-amp, just as in your picture.  I also don't have anything connected to the ground.  I had been considering running a wire but based on your feedback I won't do that.

The probe is inside of black ABS pipe.  I cut two circles of clear plastic that fit inside the pipe.  One circle is at at the top and has a small hole in the middle.  The probe goes through the plastic and is bent so the rest hangs from that.  The bottom circle has a bigger hole, which fits around the coax connector.  This keeps the entire probe centred in the pipe.  Hopefully that description makes sense.  The idea is that the probe and pre-amp should be isolated from everything.

I have a single length of coax from the pre-amp, through a hole in my ceiling to the controller.  About 20 feet in total length.  I'm not sure about details of that coax, it was the thickest one I found in my basement.  I don't see any markings on the section that comes through my ceiling -- how could I tell if it is triple shielded?

One aspect that I'm not sure about is that the probe is mounted on a steel roof vent.  The roof is standard wood and asphault shingles.  The vent is a box that is about 1 square foot by about 2 feet high.  Instead of putting a hole in my roof I cut a hole in the middle of the vent and put the ABS through it.  The GPS receiver is on the same vent, which Google is able to show:

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As described above, it is isolated inside the pipe, but would the steel plate (about 1 square foot) affect the signal?  The bottom of the preamp is probably about 6" above the flat plate.

I should also mention that my goal isn't to get to the top of a list as a competition thing.  I'm just using it as a way to guage the effectiveness of my setup.  This is mainly because I don't have enough RF background to understand details of the signal graphs, and various tuning parameters.  My thinking that if I can get to the middle of some sorting, then I'm probably doing OK.  Your new page is a good description of what the columns mean, thanks.

That being said, I'm trying to figure out how to read the signal graph better.  The example you showed is great for helping me to understand what I'm looking for.  In comparing the two from your image, I think the problem with the top one is the repeating wave pattern?  If I try adjusting parameters, then am I trying
to get rid of steady patterns like that?

For example, here is an image I just took of the magenta line:

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I count about 6 peaks within 93.1 microseconds.  Which I think means the period is about 15.5us, or about 64.5kHz.  Should I should look for something that could be interfering at that frequency?

Is this the right approach for going about this?

I'll experiment with the manual mode.  I've been avoiding that because I don't have a strong understanding of what I'm looking for.  I'll start with your suggested values and try to get a feel for what the signal graph looks like.

Regarding updating my BT stats, is this the page I should use?

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I used the length as the dimension, should that be diameter instead?

I wasn't able to see the last link that you posted.  I think that means that my BT forum account hasn't been updated, I'll follow up with them and then try again.

Thanks again for providing so much detail.  I'm sorry that this reply got so long.  I think it happened because I don't yet know enough to understand what details are not important; it looks like I errored on the side of too much.

Offline vreihen

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Re: Reducing Interference Mode
« Reply #3 on: August 24, 2019, 10:11:00 PM »
Set all Thresholds (triggers) at 100mv and apply/save.
Set all gains at 10*10 HP ON.
Disable H Channel C, since your'e Not using it.

Can I ask a really dumb question?  I've been looking everywhere in the BT web site and controller's web interface for the manual settings ever since putting my just-finished Blue controller on line for testing last week, and I can't find them anywhere.  Is there a jumper needed somewhere on the board to make them visible?  I don't have the filter chips installed, if that's why the options are missing.  (I can't read the last link above, so I guess that I need to figure out how how to get marked as an operator in the BT forum one of these days if the answer is locked away there.)

If you wouldn't mind, can you please take a peek at station 2603 and let me know if it is clobbering the servers with junk data?  I have the E-field antenna hanging indoors from a curtain rod and just temporarily cobbled together the two BT-provided H-field ferrites on a piece of cardboard for testing, and see the controller go into interference mode every minute or so.  I don't want to swamp the servers with bad signals while I build the H-field housing and figure out how to interpret the signal data to find the final mounting locations for everything.....
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Offline vreihen

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Re: Reducing Interference Mode
« Reply #4 on: August 24, 2019, 10:30:13 PM »


I used the length as the dimension, should that be diameter instead?

I believe that you should have 200,8 for the BT-provided ferrites in the above page, if @Cutty Sark Sailor is correct.  (I haven't been able to confirm the diameter online, but 8mm looks about right by eyeball using a ruler and guessing the thickness of the shrink tubing.)  Hover over the field in a desktop web browser, and a tool tip dialog will display explaining what to enter for each input type.  Also, the E-field length should be in millimeters, so your entry of 11 may be in error.  The assembly instructions say that a 10cm (100mm) piece of wire is all that you need for an E-field probe, as the included picture shows.  I had a hunk of 14/2 romex electric outlet wire in my toolbox that I stripped for one of the 14-gauge conductors, and it barely fit under the screw terminal on the E-field board.

Let me throw in a disclaimer that I'm just starting out with BT myself, so I may be wrong or confused.....
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Offline eidsness

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Re: Reducing Interference Mode
« Reply #5 on: August 25, 2019, 08:55:02 AM »
I hadn't noticed the tooltips, thanks for pointing them out.  I've updated my page now.

I had to file down the end of my 10 gauge wire in order to fit in the terminal block, but it is pretty snug now   :lol:

Offline dupreezd

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Re: Reducing Interference Mode
« Reply #6 on: August 25, 2019, 10:51:22 AM »
I believe that you should have 200,8 for the BT-provided ferrites in the above page, if @Cutty Sark Sailor is correct.  (I haven't been able to confirm the diameter online, but 8mm looks about right by eyeball using a ruler and guessing the thickness of the shrink tubing.) 

I stripped down the heat shrink on a unused 200mm ferrite that I got with my kit. It is right at 10mm. Granted, I got this one end of 2017, maybe the new ones are different.

Can I ask a really dumb question?  I've been looking everywhere in the BT web site and controller's web interface for the manual settings

It is under the Settings tab, then Main.
Auto Adapt to Noise
Auto Amplitude Filter



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« Last Edit: August 25, 2019, 10:53:13 AM by dupreezd »
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Offline DaleReid

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Re: Reducing Interference Mode
« Reply #7 on: August 25, 2019, 01:19:36 PM »
Cutty (Mike),
I read your comment several lines below and continue to learn.  I'll wait until I return home from a meeting to analyze more of your posting.

One of my major interferences is a storm itself.  I'll be running all great and something moves by a hundred miles away and I have to crank my gains down a lot.

Remarkably, with low gains I have been used as a locator for some strikes within 10-50 miles pretty reliably.

I do find that once I'm in interference mode, I get stuck there and have to change settings, then reboot the controller to 'snap out of it' and start reporting again.

Have you ever experienced that?  How about you, Greg?
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Offline vreihen

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Re: Reducing Interference Mode
« Reply #8 on: August 25, 2019, 06:46:04 PM »
Can I ask a really dumb question?  I've been looking everywhere in the BT web site and controller's web interface for the manual settings

It is under the Settings tab, then Main.
Auto Adapt to Noise
Auto Amplitude Filter

I finally found where most of the missing settings were hiding in the controller's web interface.  When I did the initial controller config, I set an admin password (like any good IT professional does even on their home network) and stupidly left guest access enabled.  When I tried to logon using the tab, I punched in the incorrect user ID.  The controller didn't say that it didn't logon, and dropped me back at the guest status page like it had logged on.  Hence, all of the fun tabs were not visible.  Insert Homer Simpson "Doh!" here..... #-o
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Offline W0BTU

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Re: Reducing Interference Mode
« Reply #9 on: September 11, 2019, 04:49:46 PM »
In manual mode, if you enable only Auto Adapt to Noise, your stations will seldom go into interference mode.

NOTE: Do NOT enable Auto Thresholds!

This definitely improved my station's performance, even though I no longer have the type of repetitive pulse-type noise that this feature was intended for.

Feedback would be most welcome, especially from those that have tried this.

(This is not documented anywhere; I found that out by accident.)  [tup]

« Last Edit: September 12, 2019, 12:44:54 PM by W0BTU »
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Offline ke9lz

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Re: Reducing Interference Mode
« Reply #10 on: September 12, 2019, 04:29:55 PM »
In manual mode, if you enable only Auto Adapt to Noise, your stations will seldom go into interference mode.

NOTE: Do NOT enable Auto Thresholds!

This definitely improved my station's performance, even though I no longer have the type of repetitive pulse-type noise that this feature was intended for.

Feedback would be most welcome, especially from those that have tried this.

(This is not documented anywhere; I found that out by accident.)  [tup]

I have tried this but found it really made no difference on both my Red or Blue stations. 

Steve
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