Ebay Schiebel Coils came today. Specs, and thoughts.

[Brian Deese]

I bought a few of these mil surplus coils off ebay. I figure they are for the an19-2 but I dont know for sure. I spent some quality time with a scalpel,and the lcr meter. I wanted to check if they are sheilded as Eric has stated he had some that were not. These are dated nov 2006. Ok lets get to it. The TX and RX are seperate. TX inductance is 248uH, DCR 1.1 ohms. Q 1.9@1kHz. RX inductance is 466uH, DCR 3.0 ohms. Q 1.1@1kHz. Inside the cable are 5 wires, two are actually coax, two are stranded, and are connected to the sheilds of their corresponding coax. I am guessing that is so you are not depending on the coax braid to carry current? The 5th wire is connected to the tx,I assume it is a detection circuit to be sure the unit is working. It has a 6 pin connector, 2 for rx,2 for tx,and two are connected together but not to anything else as far as I can tell. So I have no way to tell if the actual winding is shielded. I will look up the socket for this plug on it and hook it up to a test rig. Looks like it will be a good coil.

[Brian Deese]

Smaller Picture

[mschmahl]

I think I had 2 wire for RX and 2 wire for TX. The 5th wire is only a white plastic cord. Maybe the shield is connected inside the coilhousing to the "cold" coil-leads. But my schiebel coils are much older

[Geophyz]

Here is a photo of the 4-wire Schiebel cable from the un-sheilded version of their coil. The older version did not have any coax, just 4 wire and the white wrap cord and also a smaller white/black thread.

[mschmahl]

Thanks. That is what I have found.

[Ferric Toes]

The coils I have are 'old Schiebel'. One problem I had is that part of the shaft is aluminium and if the coil lead is wrapped loosely around this, you get false signals as the cable moves relative to the shaft. The coax should cure this but whether the later coils also have shielding, I'm not sure.
Unshielded coils also give falsing if you touch a wet saltwater beach, or even seaweed. That is one way of telling. The other way is to take a hacksaw and cut through the coil so that you can see a cross section. Obviously, it is best to use an already broken coil and I have heard that there are plenty, if you can find them.

Eric.

[Brian Deese]

Wow that is interesting,looks like so cord.

Here is a photo of the 4-wire Schiebel cable from the un-sheilded version of their coil. The older version did not have any coax, just 4 wire and the white wrap cord and also a smaller white/black thread.
[ATTACH]37254[/ATTACH]

[Brian Deese]

Receptacles

I found the receptacles 62gb-50t10-06sn they have them at farnell in the UK but I havent found them here in the states. 45 dollars each,yuk. I will pay them I guess,i sure dont want to rework connections on that micro coax.

[Geophyz]

Wow that is interesting,looks like so cord.

The 4-wire is very flexible stuff, I kept the cable off a broken coil and use it on another instrument. The jacket is extra thick, probably polyurethane.