SEF Coil?

[Raven357]

Question about 10x12 S.E.F. coil on MXT. This evening I noticed constant falsing at the end of swing and when the coil makes contact with the ground.
Is that normal for this coil?

 

[Monte]

Question about 10x12 S.E.F. coil on MXT. This evening I noticed constant falsing at the end of swing and when the coil makes contact with the ground.

Is that normal for this coil?

Sometimes you can get 'falsing' at the end of a swing, if the coil is swept up and away from the ground in an inappropriate arc type sweep. This can be due to an abrupt change due to it's move away from the ground signal. It can sometimes be caused by an improper Ground Balance, but it all depends upon the particular coil/detector design and set-up.

Also, if the end-of-sweep is an abrupt pause and return sweep the other direction you can get some falsing. This is often caused by using a too-brisk sweep and abrupt reverse direction when using a slow-motion, quick-response model. It can also happen if the internal windings and circuitry in the coil are loose and the brisk change of sweep causes some jarring or movement of the internal components.

It is possible to get a 'false signal' if a search coil makes contact with the ground, and is sometimes just due to an abrupt jarring of the search coils inner windings or circuitry. So, while it is possible that this could be the result of improper sweep control, or even poor control settings (even possibly a too-high Gain or Sensitivity setting), I would first consider it an issue with the search coil construction.

I had a 10X12 SEF that I used on an M6, MXT and Vision units that I had and never had the issues you mention. I have, however, heard of a couple of cases where they had similar problems that you mention with the 19X12 SEF on their MXT, but not with the stock 950 or 12" or two smaller accessory coils.

Thus, a conclusion is that it would appear the SEF coil was the cause. How do your others coils function with similar settings and operation?

Monte