Free lunch

[Kev]

Hi,
The old detector operator adage "dig em all!" does pay off especially when fossicking for gold. This is not one of those "dug a large 'obviously' trash signal and found a 2 oz nug

 

[dfxone]

Kev, where did you find this nugget? Along the beach on the west coast? Interesting story. All gold nuggets are beautiful to me. Great find. GH, Don

 

[Kev]

Hi Don,
It looks like a Coast piece, but it

 

[Eric Foster]

Hi Kev,

Nice little nugget. Did you get much signal from the ground in that location?

Eric.

 

[Kev]

Hi Eric,
Thanks, the way things are going with the gold price she might buy me dinner as well as lunch!

These little pieces are coming from raised alluvium which is again passing through an eluvial phase, who knows how many times Au gets recycled, anyway the ground is hot, so much so that I think it would send a lot of VLFs into the weeds! If I use my stock 11" mono I get 2 or 3 seemingly legitimate signals each pass of the coil, only problem is on the next pass they will have moved positions. At one point I accidentally knocked my DD/Mono switch so that my DD was running in mono mode, it took me a while to realise why the ground had all of a sudden gone to blazes.

I've been meaning to make a post to you Eric. Before Xmas I was balancing a DD to take on holidays and found that a relationship appeared to exist between DD coil overlap, and hence balance or counter, and the point at which the Tx and Rx coils are dampened.
I observed that the damping point affected a well balanced coils ability to detect small gold and it's level of hot rock nulling.

I'll post some osc screen dumps when I get time that will explain better, but I suspect that you already are quite conversant with all I've said.

Cheers
Kev.

 

[Eric Foster]

Hi Kev,

There is still a lot to investigate regarding coils and particularly the overlap in DD's. It's a different ball game with PI's, as you are setting it up for different reasons than you would for a VLF. I probably have not gone into this as far as you have, so any results or suggestion would be welcome.

One potential problem I see with a DD, is that it gives good cancellation over fairly uniform ground, but an individual hotrock could give a signal as it passes the coil crossover points. This is because, at those two points, the TX and RX are closely coupled. One solution is to bridge one winding over the other, to give some vertical separation. This possible signal would fall off very rapidly with distance, so it may only occur if you are virtually scrubbing the ground.

Eric.

 

[Anonymous]

n/t

 

[Kev]

n/t