Topic: Adding E Field Probe - Startup and Operation - not for construction

[dfroula]

One issue that my diagrams don't show...if the "hidden" Amp1, Channel C threshold is set higher than the Channel C threshold on Amp2, the "hidden" threshold will be used instead of the C threshold set on Amp 2. The only way to get the hidden value to show on the settings page is to force all channels on, then be sure the Channel C thresholds for both amps are set the same.

I'll try to rework the diagrams to show this clearly.

Don
WD9DMP

Once an E-field amp is added, setting the gains and thresholds is no longer as straightforward as before!

In my opinion, enabling "Alternate Channel Mapping" is an absolute must. The attached images attempt to show why.

Keep in mind that overall "relative gain" of a channel is affected by two things - the gains set on the op-amps (either fixed or adjustable) and the threshold settings. The apparent or "relative" gain can be increased by by increasing the gain on an adjustable op-amp stage or by reducing the threshold on that same channel. Conversely, the apparent or "relative" gain can decreased by decreasing the gain or increasing the threshold.

Gains are set on the amp board(s). Thresholds are set on the Analog to Digital Converters (ADCs) on the STM32F4Discovery board. The STM32F4Discovery has 3 ADCs, each with two channels. After the E-field amp is added, those six available ADCs need to be mapped to the five total channels of the two amps in a way that allows the channel thresholds to be adjusted for one amp without affecting the other. Compromises need to be made. Only the "Alternate Channel Mapping" option allow threshold settings of one amp to be made without affecting the settings of the other amp.

This is particularly important if the "Auto Adjust to Noise" feature is also enabled. That feature does fast relative gain adjustments in response to local noise by varying the thresholds. A slower adjustment is done by changing the gain of the adjustable op-amps on the channel experiencing the noise. Standard channel mapping will move the threshold of a channel on one amp, but unless "Alternate Channel Mapping" is enabled, the associated threshold on the other amp will change as well, even though it may not be experiencing the noise!

The same problem exists somewhat even with "Alternate Channel Mapping" enabled, as the thresholds of channels A and B on the same amp are now shared. However, at least the common threshold will now be on the same amp, where the noise source is more likely to be common. This allows the "Auto Adjust to Noise" feature to do a better job at reducing the effects of transient noise.

Best regards,

Don

[Cutty Sark Sailor]

One issue that my diagrams don't show...if the "hidden" Amp1, Channel C threshold is set higher than the Channel C threshold on Amp2, the "hidden" threshold will be used instead of the C threshold set on Amp 2. The only way to get the hidden value to show on the settings page is to force all channels on, then be sure the Channel C thresholds for both amps are set the same.

I'll try to rework the diagrams to show this clearly.

Don
WD9DMP

Once an E-field amp is added, setting the gains and thresholds is no longer as straightforward as before!

In my opinion, enabling "Alternate Channel Mapping" is an absolute must. The attached images attempt to show why.

Keep in mind that overall "relative gain" of a channel is affected by two things - the gains set on the op-amps (either fixed or adjustable) and the threshold settings. The apparent or "relative" gain can be increased by by increasing the gain on an adjustable op-amp stage or by reducing the threshold on that same channel. Conversely, the apparent or "relative" gain can decreased by decreasing the gain or increasing the threshold.

Gains are set on the amp board(s). Thresholds are set on the Analog to Digital Converters (ADCs) on the STM32F4Discovery board. The STM32F4Discovery has 3 ADCs, each with two channels. After the E-field amp is added, those six available ADCs need to be mapped to the five total channels of the two amps in a way that allows the channel thresholds to be adjusted for one amp without affecting the other. Compromises need to be made. Only the "Alternate Channel Mapping" option allow threshold settings of one amp to be made without affecting the settings of the other amp.

This is particularly important if the "Auto Adjust to Noise" feature is also enabled. That feature does fast relative gain adjustments in response to local noise by varying the thresholds. A slower adjustment is done by changing the gain of the adjustable op-amps on the channel experiencing the noise. Standard channel mapping will move the threshold of a channel on one amp, but unless "Alternate Channel Mapping" is enabled, the associated threshold on the other amp will change as well, even though it may not be experiencing the noise!

The same problem exists somewhat even with "Alternate Channel Mapping" enabled, as the thresholds of channels A and B on the same amp are now shared. However, at least the common threshold will now be on the same amp, where the noise source is more likely to be common. This allows the "Auto Adjust to Noise" feature to do a better job at reducing the effects of transient noise.

Best regards,

Don

Yes, setting them the same is great!

You might also try to set the 'hidden' to the 'lowest' threshold you think you might want to use for E field C... you may find a time you'll want to go lower, and you won't be able to, unless you've 'preset' a lower figure in the "hidden" C... You'll always be able to set your E field C higher, but not go lower than your "Hidden" channel C

[dfroula]

Carrying this one step farther, turn on "Force all channels on" and set Amp 1, Channel C to the minimum value, 1mV. Then turn off "Force all channels on". Now, the Amp 2, Channel C threshold will be assured of being the value set in the Amp 2 settings.

If this is done as a one-time setup, the two jpegs I posted earlier will be correct.

Don

You might also try to set the 'hidden' to the 'lowest' threshold you think you might want to use for E field C... you may find a time you'll want to go lower, and you won't be able to, unless you've 'preset' a lower figure in the "hidden" C... You'll always be able to set your E field C higher, but not go lower than your "Hidden" channel C

[Cutty Sark Sailor]

Carrying this one step farther, turn on "Force all channels on" and set Amp 1, Channel C to the minimum value, 1mV. Then turn off "Force all channels on". Now, the Amp 2, Channel C threshold will be assured of being the value set in the Amp 2 settings.

If this is done as a one-time setup, the two jpegs I posted earlier will be correct.

Don

You might also try to set the 'hidden' to the 'lowest' threshold you think you might want to use for E field C... you may find a time you'll want to go lower, and you won't be able to, unless you've 'preset' a lower figure in the "hidden" C... You'll always be able to set your E field C higher, but not go lower than your "Hidden" channel C

Added Don's "Keep it Simple" solution to avoid 'threshold' confusion, and revised that portion considerably.  Thanks, Don!

[W7DRM (old call was W3DRM)]

Just got home after a 7-hour drive (two-way) and I see you guys are making changes to the procedure... 

Anyway, while looking to see what has changed I noticed something that might confuse a newbie (well, it confused me...).

In the following section, it states:

"Suggested intial settings:

Run in manual mode. You want control with fixed parameters for awhile.
Turn off all filters..."

Looking at the referenced image, I only see one thing that seems to be related to "filters". It reads "Auto Amplitude Filter". Is this the selection you are referring to or am I missing something? If it is only that one then shouldn't it read "Turn OFF (or deselect) the Auto Amplitude Filter selection?

I also see a typo where it says "Suggested intial settings:" Should be "initial".

Will work on getting my supplementary document updated tomorrow.

[dfroula]

There are two filter mechanisms. The first is the "Ignore signals below threshold" filter. This determines whether a signal on a channel is transmitted to the servers when another channel reaches the threshold value. When this "trigger" occurs, the info from the other channels will also be sent if their amplitude at the time of the trigger is >= the specified percentage of the threshold setting for that channel. This value should be left at the default 10%. For example, if Channel A reaches its trigger threshold of, say, 120mV, the other active channels, say Channel B, will be evaluated to see if their amplitudes are at least at 10% of their threshold settings. If it is, the transmitted UDP packet will contain data for that channel(s) as well. This can be effectively disabled by setting the "Ignore signals below threshold" to 100%. Then, only if a channel exceeds its own threshold value will it be sent. It is a bad idea to do so, since the servers will not see supplementary information from the other channels - particularly with the E-field amp, which an also be used to determine strike polarity and intensity, even if the E-field channels did not reach their own trigger thresholds. You do not want to disable this filter.

The other filter is the "Auto Amplitude Filter", which can remove certain high-amplitude noise sources that have a very regular interval. It is this filter that should not be enabled, at least for initial setup.

Best regards,

Don
WD9DMP

[DaleReid]

Don,
A VERY clear explanation.  I had no idea on how those worked in detail.

Thanks.
Dale

[Cutty Sark Sailor]

Right... sorry about that.. I was referring to the automatic modes, auto noise, and auto amplitude... I've gone back and specified those in that portion... thanks.,. Reason for not running those is to begin the process of tracing any interference, if necessary, and to also "prove" that the amps are working and other adjustments, etc, work as designed.
 

[W7DRM (old call was W3DRM)]

Mike & DonF,

Thanks for the clarification and answering my questions as well as though of other members.

You two have really dug into the theory and operational aspects of this entire Blitzortung system. I think everyone who reads these posts will gain from your explanations and experiences. I certainly have and thank you both for your contributions to this project.

[Cutty Sark Sailor]

Well, Don and I both figure if we can keep you all confused enough... 

[miraculon]

I decided to go "Full Automatic" and enjoy the ride...
It does sound like you guys are tweaking to your hearts content, though.

Greg H.

[W7DRM (old call was W3DRM)]

The latest version of the Startup and Operation document has been uploaded. The link to it can be found in the first post of the Blitzortung Documentation thread:

• http://www.wxforum.net/index.php?topic=20037.0

[W7DRM (old call was W3DRM)]

Wow, since going through the steps that Mike & DonF have provided for us, I am noticing a much higher level of "Good" signals than I did when I had everything set in "Automatic" mode. I'm running in Manual Mode starting off with the settings suggested. I did have to lower some of the Amp settings and also raised the threshold settings for Amp 1 due to constant interference mode with the default settings.

All of this with both Ferrite and E-field antennas sitting in my office pretty much surrounded by computers and electronic gear. The outside move is still planned but time to do it just hasn't been on the board, as yet.

I've attached a few screen captures of the Tracker Status Graph that shows the dramatic jump in Good signals.

[W7DRM (old call was W3DRM)]

Mike,

Where are the "Spectrum" jpegs found? I see the "Raw Signals" jpegs on bo.org but can't figure out where the others are.

[Cutty Sark Sailor]

Don...
check your pm

[Cutty Sark Sailor]

7/13/2014 ADDED THE FOLLOWING NOTE TO PRIMARY POST:
You CANNOT DISABLE E-field signals by checking "don't send" on the settings page. The server wants to see all three channels. Best you can do is set gains to 1x1, thresholds to "0". You can adjust gains.

[Silversword]

Hi All,

I have a question as to the distance for this antenna system will cover?  If it does not go beyond my surrounding body of water, it would not be worth installing this antenna at my location.

Any thoughts on this?

Regards,

--Stan Y.
   Maui, Hawaii

[Cutty Sark Sailor]

Hi All,

I have a question as to the distance for this antenna system will cover?  If it does not go beyond my surrounding body of water, it would not be worth installing this antenna at my location.

Any thoughts on this?

Regards,

--Stan Y.
   Maui, Hawaii

Ahhh.... Stan....
The 'issue' with E field, is it's extremely sensitive...  I've said once or twice, that a receiver could probably get lightning on Jupiter, if we could get the signals through the ionosphere!

Because of the sensitivity, it will pick up anything in the filtered bands, up to 50Khz... anything -- from all directions. Aurora from the South Pole, if set right. That's one thing that limits the range.... too many signals... so the "gain" of the preamp is actually a reduction! Those of us who have a quiet enough environment can pretty much equal the H field's reception if we choose... but that 's not what it's designed for, and those long range signals will likely be 'useless' for the intent.

It's designed to be utilized for shorter range... under 500 miles.  The C channel is the critical channel, and is virtually the same data, omnidirectional, of the output of the (directional) H field. The A and B channels have other purposes... eventually for precision stroke info such as type, polarity, etc.  Used with the H field signal, many more things will be possible.

So, it's not whether the system is valuable or not... it's because you are out there keeping the faith, alone, opening the store every day, but no customers.  Because whichever system is used, single or dual, it still takes 3 pairs of stations ( a minimum of 4 stations in other words) to locate a signal.

If it were me, I'd go for it anyway.  One reason, --when the interest hits Hiawaii, other stations need the old pro, who sat there with the candle in the window waiting for visitors. Able to tell them things like "the fleet's on exercise, that noise will go away in 72 hours... don't worry about it'. 

Plus  the pretty Magenta and Teal and Orange signal traces added to the Green and Red are kinda fun to look at...

Hang in there! Virginia City Nevada just went on line... sooner or later we may get enough western stations with an environment that will allow them to 'crank up' and help you until the Islanders wake up!

Mike

[Silversword]

Hi,

Thanks Mike for the info.  I wrote to support at BO and see if they had any on stock but they are out at this time.  Tobias relied and suggested that being out here may not make a difference and I still need to figure out my noise issue.  Have not been able to work on this as too many things got to my time to work on it..

Maybe this weekend I'll be able to put some time into it.

Thanks again for your input and suggestion.

--Stan Y.
   Maui, Hawaii

[Cutty Sark Sailor]

Thought I'd give this aging thread a bump, since the info is still valid.  A lot has been gleaned from the E field addition to system RED.  The info and data, and signal quality we've supplied are going to make the next generation of BO hardware something to astound folks.  You might expect some 'dramatic' changes in approach and signal processing. Some will be surprising, I expect, but I wouldn't be surprised to see those of us who may hook up with 'System 3' (whatever color it winds up being    )  sitting in front of our monitors at this time next year with our jaws gaping....   

[DaleReid]

Hey, I'm pretty amazed already!

My little solo Efield was looking down into Texas and the Gulf seeing strikes yesterday and today.

Hows that for astounding.

[Maumelle Weather]

Hi Folks,

Finally got my E-field online yesterday, thanks to Jumpin Joe. I initially had used the CAT5 connection that came with the E filed kit on my Red controller, because when I originally ordered the Red, it only had one normal CAT 5 connection with it, instead of 2. So, after looking here, I saw where Don (Minden, NV) had ordered some more off of Ebay. He was kind enough to send me the part #.  I ordered those. Then I went to work on building the E field kit. Got the kit built, got the connectors in.  Assembled everything, (after placing one of the SMD's in the wrong spot).  Took everything out to the Red location, plugged it in and.....nothing happened. No power, lights, etc.  Needless to say I was bummed. Brought the E field back into the house, went over it with a 10X magnifying glass, and couldn't see anything wrong.

Long story made short is the connector I had gotten had an internal power connection built into it that wasn't allowing anything to work. Joe tracked it down for me. I would have never considered that being the problem.

It is currently detecting some of the strokes out in the Gulf of Mexico, some 500-700 miles away from me. The preamp/antenna is currently inside my shed about 8 feet above the ground, and about 4 feet away from the H field antenna, which my explain some of the additional noise I am seeing. I'm open to suggestions as to its final placement.

Thanks,

John

[Cutty Sark Sailor]

Good show, John... 
(And Limpin' Joe (temporay) er... Jumpin Joe.)
Your sigs look good on H field...
E field probe/preamp assy needs to be OUTSIDE....   away from the shed.  8-12 feet high should be fine. Mine's 21', I think.

Mike

[Cutty Sark Sailor]

  This topic needs to be bumped.  Especially with the new "Blue" system on the horizon... So, here... "BUMP", dang it...

[orion_jb2001]

Hi all,

I am just about to do some pre season maintenance work on my set up and am just going over posts in general.  How critical in all this is the  channel threshold settings? ALso is there a link to somewhere that goes more into these particular settings?

Jeff