From: <hvanesce@comcast.net>
To: <rsgb_lf_group@blacksheep.org>
Date: Thu, 14 Feb 2019 15:50:15 -0500
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Subject: LF: QRM - Other
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This popular item doesn't seem particularly friendly for ULF-VLF; 40 to 76
turns wrapped around the home's water main pipe, ~ 2 amps out, sweeping 1
kHz to 20 kHz every 50 milliseconds.

https://www.scaleblaster.com/wp-content/uploads/docs/spec-max.pdf

https://www.scaleblaster.com/wp-content/uploads/docs/installation-max.pdf

which would seem to give roughly 40 fT at 100m at for the specified 70 turns
on 4 cm water main, not counting eddy currents in the copper pipe.

Not sure how current varies* with frequency in these devices, or how
rectangular the current waveform is.

  * (guessing current varies as 1/f, which would mean roughly 30 fT at 50m
at 10 kHz)

 
A commercial unit provides 10A-40A into a 200uH coil around the water main
(less current into the nominal 1 mH coil):

https://www.scaleblaster.com/wp-content/uploads/2016/08/SB-4000-clm276.pdf

https://www.scaleblaster.com/wp-content/uploads/2016/07/Sb1200-SB4000-Instal
l-Operations-Manual.pdf

which would seem to give roughly 10 fT at 1 km for the specified 7 turns on
106 cm water main.

 
- Jim AA5BW  


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vlink=3Dpurple><div class=3DWordSection1><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>This popular =
item doesn&#8217;t seem particularly friendly for ULF-VLF; 40 to 76 =
turns wrapped around the home&#8217;s water main pipe, ~ 2 amps out, =
sweeping 1 kHz to 20 kHz every 50 milliseconds.<o:p></o:p></p><p =
class=3DMsoNormal><a =
href=3D"https://www.scaleblaster.com/wp-content/uploads/docs/spec-max.pdf=
">https://www.scaleblaster.com/wp-content/uploads/docs/spec-max.pdf</a><o=
:p></o:p></p><p class=3DMsoNormal><a =
href=3D"https://www.scaleblaster.com/wp-content/uploads/docs/installation=
-max.pdf">https://www.scaleblaster.com/wp-content/uploads/docs/installati=
on-max.pdf</a><o:p></o:p></p><p class=3DMsoNormal>which would seem to =
give roughly 40 fT at 100m at for the specified 70 turns on 4 cm water =
main, not counting eddy currents in the copper pipe.<o:p></o:p></p><p =
class=3DMsoNormal>Not sure how current varies* with frequency in these =
devices, or how rectangular the current waveform is.<o:p></o:p></p><p =
class=3DMsoNormal>&nbsp; * (guessing current varies as 1/f, which would =
mean roughly 30 fT at 50m at 10 kHz)<o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>A commercial =
unit provides 10A-40A into a 200uH coil around the water main (less =
current into the nominal 1 mH coil):<o:p></o:p></p><p =
class=3DMsoNormal><a =
href=3D"https://www.scaleblaster.com/wp-content/uploads/2016/08/SB-4000-c=
lm276.pdf">https://www.scaleblaster.com/wp-content/uploads/2016/08/SB-400=
0-clm276.pdf</a><o:p></o:p></p><p class=3DMsoNormal><a =
href=3D"https://www.scaleblaster.com/wp-content/uploads/2016/07/Sb1200-SB=
4000-Install-Operations-Manual.pdf">https://www.scaleblaster.com/wp-conte=
nt/uploads/2016/07/Sb1200-SB4000-Install-Operations-Manual.pdf</a><o:p></=
o:p></p><p class=3DMsoNormal>which would seem to give roughly 10 fT at 1 =
km for the specified 7 turns on 106 cm water main.<o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>- Jim AA5BW =
&nbsp;<o:p></o:p></p></div></body></html>
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