It ran throughout the mine and the mine layout was such that it was basically a vertical loop that was pinched in the middle with two lobes either side. Basically it ran up in the top corner of tunnels, and just hung vertically in ventilation shafts and boreholes when needed.
Gauge was about 6 or 8 mm2 edit: 10mm2 (8 AWG), from memory the overall loop resistance was about 20 ohms.
Plenty of splices due to damage from heavy equipment, and there were a few spots where we could break the loop and test which part was shorted or open.
You could use just standard electrical wire connections like BPs as it wasn’t particularly high voltage or current and there was no attempt to make it radiate “nicely”, plenty of spots where we used twin core cabling to extend the loop to some section and basically the opposing currents would cancel the field on that length of twin.
Used for underground messaging and blasting. If you search for " MST PED system" you might find some info, it’s pretty obsolete now that most places use Wi-Fi and vhf uhf radio on leaky feeder underground.
You could normally blame your GSM phone for that, it would be woken up by a cell tower to do a bit of high powered chatter before actually ringing or receiving a SMS.
Mining?
Also, how did you spread your loop? Was it continuous or did you have splices? What gauge was it? Was it just lying on the ground?
Yep, mining.
It ran throughout the mine and the mine layout was such that it was basically a vertical loop that was pinched in the middle with two lobes either side. Basically it ran up in the top corner of tunnels, and just hung vertically in ventilation shafts and boreholes when needed.
Gauge was about
6 or 8 mm2edit: 10mm2 (8 AWG), from memory the overall loop resistance was about 20 ohms.Plenty of splices due to damage from heavy equipment, and there were a few spots where we could break the loop and test which part was shorted or open.
You could use just standard electrical wire connections like BPs as it wasn’t particularly high voltage or current and there was no attempt to make it radiate “nicely”, plenty of spots where we used twin core cabling to extend the loop to some section and basically the opposing currents would cancel the field on that length of twin.
Used for underground messaging and blasting. If you search for " MST PED system" you might find some info, it’s pretty obsolete now that most places use Wi-Fi and vhf uhf radio on leaky feeder underground.
I was about to blame you for the sounds my pc speakers used to make, but I didn’t live near any mines.
You could normally blame your GSM phone for that, it would be woken up by a cell tower to do a bit of high powered chatter before actually ringing or receiving a SMS.
TIL, Dave is cool