Noise spikes on board, System Blue
#1
I'm seeing noise spikes which appear on the board. These spikes still appear with the H-field pre-amplifier unplugged. I'm guessing this could be the result of me not grounding the board? It only happens on channel 1A.

[Image: RWRJeHh.png]
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#2
(2016-06-15, 13:06)Jorgeminator Wrote: I'm seeing noise spikes which appear on the board. These spikes still appear with the H-field pre-amplifier unplugged. I'm guessing this could be the result of me not grounding the board? It only happens on channel 1A.

[Image: RWRJeHh.png]

I also see those....
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#3
(2016-06-15, 15:08)Andrew.Instone-Cowie Wrote:
(2016-06-15, 13:06)Jorgeminator Wrote: I'm seeing noise spikes which appear on the board. These spikes still appear with the H-field pre-amplifier unplugged. I'm guessing this could be the result of me not grounding the board? It only happens on channel 1A.

[Image: RWRJeHh.png]

I also see those....

I tried grounding the board at the SMA connector like Richo said in another thread, but the spikes are still present. Otherwise the noise suppression and detection rates are excellent, I'm picking up strikes as far away as Turkey and Siberia (3000-5000km) with the 200mm ferrite rods.
One noise source that I'm aware of is our induction cooktop, the noise goes through the roof when someone is cooking.
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#4
These spikes come from the board itself, but only on the first channel (red) because it's too close to the network controller and not well isolated from the digital part. I've already seen that on my (beta) board and reported it, but it seems there was not enough time to fix/investigate that.

The spikes can be lowered a bit by disabling the high-pass filter (-> HP off). Please change the gain from 5*16 to 16*5. The overall gain of the BLUE system is really high and the first stage should always be higher than the second one.
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#5
(2016-06-15, 13:06)Jorgeminator Wrote: I'm seeing noise spikes which appear on the board. These spikes still appear with the H-field pre-amplifier unplugged. I'm guessing this could be the result of me not grounding the board? It only happens on channel 1A.

[Image: RWRJeHh.png]


What are you using as an oscilloscope ?  I'm interested in getting one and would like some ideas of what to start looking at

Thanks
Michael
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#6
(2016-06-16, 22:33)mhbeach Wrote:
(2016-06-15, 13:06)Jorgeminator Wrote: I'm seeing noise spikes which appear on the board. These spikes still appear with the H-field pre-amplifier unplugged. I'm guessing this could be the result of me not grounding the board? It only happens on channel 1A.

[Image: RWRJeHh.png]


What are you using as an oscilloscope ?  I'm interested in getting one and would like some ideas of what to start looking at

Thanks
Michael

No oscilloscope, the signals can be viewed through the web interface  Smile 
If there's a lot of lightning activity it can be difficult to spot the "false positives" since the signals stay on the screen only for a fraction of a second.
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#7
(2016-06-16, 23:09)Jorgeminator Wrote:
(2016-06-16, 22:33)mhbeach Wrote:
(2016-06-15, 13:06)Jorgeminator Wrote: I'm seeing noise spikes which appear on the board. These spikes still appear with the H-field pre-amplifier unplugged. I'm guessing this could be the result of me not grounding the board? It only happens on channel 1A.

[Image: RWRJeHh.png]


What are you using as an oscilloscope ?  I'm interested in getting one and would like some ideas of what to start looking at

Thanks
Michael

No oscilloscope, the signals can be viewed through the web interface  Smile 
If there's a lot of lightning activity it can be difficult to spot the "false positives" since the signals stay on the screen only for a fraction of a second.

Thanks !! - I'm still waiting for my System Blue to arrive - good to know I don't need a scope
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#8
(2016-06-16, 20:58)Tobi Wrote: These spikes come from the board itself, but only on the first channel (red) because it's too close to the network controller and not well isolated from the digital part. I've already seen that on my (beta) board and reported it, but it seems there was not enough time to fix/investigate that.

The spikes can be lowered a bit by disabling the high-pass filter (-> HP off). Please change the gain from 5*16 to 16*5. The overall gain of the BLUE system is really high and the first stage should always be higher than the second one.

Thanks Tobi, disabling the high-pass filter did the trick. The overall noise also decreased.
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#9
HP-Filter is first of all a mains filter

If you do not have that noise, cut it off, as it also have en extra gain you do not need

/Richo


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