DD coil

[Mark-VA]

In regards to a DD coil, anyway to know which side is the transmit coil?

[dfbowers]

Without getting fancy, get a roll of magnet wire from Radio shack. Wind it around a ferrite slug, say 100 turns or so. If you don't have a ferrite slug just use the roll of magnet wire. Hook both ends to a digital voltmeter and set the meter to the lowest A.C. setting. Move the sniffer coil (that you just made) over both sides of the coil. Make sure that your sniffer coil is oriented vertically (hole on top or slug pointed upwards). It should be obvious.

[HECTOR]

In regards to a DD coil, anyway to know which side is the transmit coil?

Radio Shack also used to sell telephone pickups (the kind with a little suction cup) for recording conversations. I have one of those and it is ideal.

[Carl-NC]

Most of the time the cable hole is on the TX side.

[kt315]

with more fat wire.

[Carl-NC]

with more fat wire.

True, if you have an x-ray machine. (I do.)

[Davor]

You bought it for your mother in law and said it was a bed lamp?

I worked on re-fitting industrial x-rays long ago, changing the tube's nappies and transformer oil, vacuum them and build-up to 100kV. The tubes are so nice looking on their own. Not so nice if you are in front of them while operating.

[mikebg]

Where is placed TX winding

You bought it for your mother in law and said it was a bed lamp?

I worked on re-fitting industrial x-rays long ago, changing the tube's nappies and transformer oil, vacuum them and build-up to 100kV. The tubes are so nice looking on their own. Not so nice if you are in front of them while operating.

HI Davor!
We are colleagues in terms of x-ray equipment service. I do the same thing, but in medical systems for diagnosis and therapy. Use a mirror to watch the temperature of the anode path, because the mirror can't reflect X-rays.

As to determining where the TX winding is placed, I suggest two ways:
1. By weight. If the search head is on a stem with axis of symmetry, it will lean towards the heavier part where the TX winding is. Place the rod on a table and then try to balance the search head on it.
2. By generated TX field when the machine is running. You need a coil which is connected to an AC meter or a red LED. No need of resistor R.

[F117]

Have a look here: http://www.geotech1.com/forums/showt...attery-charger
A small relay coil and a high-bright LED (with/without series resistor) will do the trick.

Regards,
- Bernard

[deemon]

The most simple trick is to glue a little magnet to a paper sheet and bring it to the coil .... near the transmit coil we'll hear a quiet sound

[golfnut]

The most simple trick is to glue a little magnet to a paper sheet and bring it to the coil .... near the transmit coil we'll hear a quiet sound

off up a small speaker - 1 or 2" dia or a cellphone speaker.

May have to short the terminals together with bit of wire, may not?

S

[deemon]

off up a small speaker - 1 or 2" dia or a cellphone speaker.

May have to short the terminals together with bit of wire, may not?

S

Yes , I tried this trick too - sound appears when the terminals are shorted , of course .