Method and apparatus for a sensor wire

1. A method of making a cable, the method comprising the steps of:

wrapping an insulation layer substantially about a conductor;

applying a foamable polymer layer substantially about the insulation layer, wherein a cross-section of the foamable polymer layer has a substantially uneven outer surface;

welding an armor shell, wherein the armor shell is exterior to the foamable polymer layer, wherein the armor shell is substantially concentric to the conductor; and

leaving at least one contiguous pneumatic void along a length of the cable between the substantially uneven outer surface of the foamable polymer layer and the armor shell.

2. The method of claim 1 , further comprising:

testing a weld integrity of the armor shell; and

foaming the foamable polymer layer.

3. The method of claim 2 , wherein the step of testing the weld integrity further comprises performing a hydrostatic pressure test of the weld integrity of the armor shell.

4. The method of claim 1 , wherein the step of applying the foamable polymer layer further comprises:

applying the foamable polymer layer substantially about the insulation layer, wherein the cross-section of the foamable polymer layer has a substantially even outer surface; and

extruding the foamable polymer layer, wherein the cross-section of the foamable polymer layer has the substantially uneven outer surface.

5. The method of claim 4 , wherein the step of extruding the foamable polymer layer, further comprises striating the foamable polymer layer.

6. The method of claim 5 , wherein the step of striating the foamable polymer layer further comprises creating between 2 and approximately 30 striations in the foamable polymer layer.

7. The method of claim 1 , further comprises the step of forming a plurality of pneumatic voids between the armor shell and the foamable polymer layer along the length of the cable.

8. A method of making a cable, the method comprising the steps of:

applying a fluoropolymer insulation layer substantially about a conductor;

extruding a foamable polymer layer substantially about the fluoropolymer insulation layer, wherein a cross-section of the foamable polymer layer has a substantially uneven outer surface; and

longitudinally welding an armor shell that is exterior to the foamable polymer layer, wherein the armor shell is substantially concentric to the conductor.

9. The method of claim 8 , further comprising:

testing the weld integrity of the armor shell, wherein the step of testing includes at least one of an inert gas pressure test and a hydrostatic test; and

foaming the foamable polymer layer, thereby expanding the foamable polymer layer and filling at least one pneumatic void, whereby the foamable polymer layer becomes a foamed polymer layer.

10. The method of claim 8 , wherein the step of extruding the foamable polymer layer further comprises:

extruding the foamable polymer layer substantially about the insulation layer without activating the foamable polymer layer, wherein the cross-section of the foamable polymer layer has a substantially even outer surface.

11. The method of claim 10 , further comprising extruding a plurality of peaks and a plurality of valleys into the foamable polymer layer, thereby creating a plurality of contiguous pneumatic voids between the foamable polymer layer and the armor shell along a length of the cable.

12. The method of claim 10 , wherein the step of extruding the foamable polymer layer, further comprises striating the foamable polymer layer.

13. The method of claim 12 , wherein the step of striating the foamable polymer layer further comprises extruding between 2 and approximately 30 striations in the foamable polymer layer, thereby leaving a plurality of pneumatic voids between the armor shell and the foamable polymer layer along the length of the cable.

14. The method of claim 8 , further comprises the step of forming a plurality of pneumatic voids between the armor shell and the foamable polymer layer.