My low interwinding capacitance coil for CHANCE PI and CLONE PI

[baum7154]

I just made 3 coil for comparison with the same inductance, wire diameter and coil diameter..the 3dss type has doubled the capacitance compare to spider wave and flat spiral coil..

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It I not surprising that the 3DSS coil has more capacitance than an unshielded spiral or spider or basket wound coil but once shielded these coils loose a LOT of speed. What, if any, feedline do you have on the coils? Feedlines are major capacitance contributors and should be identical in any comparison of coils. Your coils should be shielded for comparison to the 3DSS coil. In the end SRF higher than about 1 MHz should be sufficient for most practical detecting of small gold.

Dan

[jladre]

Hi dan!
In my comparison test i leave about 1m of each coil wire end to be used as feedline. I found out also than even 3dss has high capacitance compare to other type, it is still superior in very small targets. Anyway about the shielding i dont have problem to it.. I alway used unshielded coil for underwater hunting.

[6666]

By the way I am thinking of making a vertical coil with this same 3DSS winding pattern to see how it performs.

Dan did you ever make this ?, I would be interested in seeing the former if thats possible please.

[baum7154]

No I did not yet , got side tracked on a machining project with a shorter time line. However I will be getting to it once the other project is completed.

[6666]

No I did not yet , got side tracked on a machining project with a shorter time line. However I will be getting to it once the other project is completed.

Dan did you ever build it ?

[baum7154]

Hi 6666,

Sorry, but I have not built it in the verticle frame format. I still plan to do it as time allows and compare it in the same tests I have repeatedly done with the horizontal frame coils. Will post the results here when completed..

Dan