Electric fence on steroids!

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Easylife
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I returned to a horse field which I first detected many years ago but now part of it has an electric fence. I was surprised that I could not escape it's pulse even when about 50m away from it. This was using a Nox 800 in multi-frequency but it was still there in single frequencies too. Maybe the 15" coil was acting as a larger aerial amplifing it but is usually as quiet as any other. There was a distinctive repetitive pattern giving three different readings, low, mid and high, more noticeable using full tones. Lowering the sensitivity to more than I am comfortable with was the only way to completely alleviate it, but I was just surprised at how strong it was! It's real bad news if that's how they make them now? Hopefully I'll get it switched off when I see the landowner. :pulling hair out:
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Saffron
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Most electric fences were powered by a normal 12 volt "car battery", you can normally detect reasonably close to these.
But they could go flat (as the fencing only drains the battery and its on 24x7) and horses / livestock soon work this out and "escape"!, and therefore needed charging and a second battery to be used when this was being done.

However, now a lot of electric fences are on a long line running around a lot of fences and powered from the mains back at the farm buildings. These are more powerful (I would not suggest holding one to test this statement!), and you will get EMI from them for a much greater distance from the fence.

Single freq reduces the problem compared to multi, but turning down sensitivity (resulting in loss of depth) is the best option. But if you can stand the noise the patterns do become recognisable. Earlier this year I found a nice crotal bell (ringer!) close to one of these fences by ignoring the patterns and recognising the clear bleep was out of sync with the EMI. However, I am sure the EMI meant I missed some genuine signals. But even here I could only manage it for about 10 minutes before having to admit the constant noise from the EMI was too much.

Evan
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Easylife
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Saffron wrote: Thu Nov 05, 2020 11:56 pm However, now a lot of electric fences are on a long line running around a lot of fences and powered from the mains back at the farm buildings. These are more powerful (I would not suggest holding one to test this statement!), and you will get EMI from them for a much greater distance from the fence.
That is exactly this, I should have said that it was mains powered. Normally I could detect through this to an extent as you suggest, but this was a very heavily detected permission (by myself) so just now listening out hard for the feint deep remaining small targets, but that's just impossible with the fence pulsing.
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Pete E
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Why not ask if you can switch the fence off for a couple of hours?

I detect a series of horse paddocks, and the owner is happy enough for me to disconnect the fence when I go in, as long as I reconnect it as I leave...
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Easylife
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Pete E wrote: Fri Nov 06, 2020 12:57 am Why not ask if you can switch the fence off for a couple of hours?

I detect a series of horse paddocks, and the owner is happy enough for me to disconnect the fence when I go in, as long as I reconnect it as I leave...
Yep, that shouldn't be an issue, just really quite surprised at how far the pulses reached!
Maybe thats the difference between battery and mains powered then?
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Easylife wrote: Fri Nov 06, 2020 1:34 am Yep, that shouldn't be an issue, just really quite surprised at how far the pulses reached!
Maybe thats the difference between battery and mains powered then?
Not just the power, but I think the frequency the operate at too...basically think of it as akin to a tazer in some respects...
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