Depth on 9 inch HF coil?

[CharlesUpstateNY]

I'm testing my new HF 9 inch coil this morning, not seeing the depth I saw on the 11 inch LF coil which is to be expected but I was a bit surprised it didn't go a bit deeper than it is on a silver dime. Air test I'd dig about 7-8 inches max does that sound right? I cranked the sense up from 90 to 95 no difference really. I'm running the machine pretty open and hot. I bought this coil for gold not silver so I'm just curious here what the expected depth would be for a silver dime. I switched between the three frequencies, all about the same depth. About the same depth on a $5 gold coin which is quite a bit larger diameter than the dime.

GOLD jewelry on the other hand holy mother of God wait...until...you...see it. I'll start a thread and post some pictures after I'm done testing.

Notch 00-00
Disc 0.0
Full Tones
Sens 90
TX Power 2
Freqency 8kHz
Iron Volume 0
Reactivity 2
Silencer -1
Audio Response 4
Audio Overload 1
ID Normalization On

 

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[vferrari]

If you were running the above settings with the 11" coil, then the 11" coil is also going to have a slight frequency (depth) advantage vs. the 9" HF coil since that coil can only run minimum of 13 khz (and you probably ran it at the default of 14 khz). If you really want to do a close comparison between the two coils depthwise, I would put the 11" at 12 khz and the 9" HF at 13 khz. That is about the closest you will get in frequency which has the most impact on depth besides coil size. Also, I am actually surprised max depth did not decrease for the dime as you increased to the higher HF frequencies and similarly that the gold piece signal did not improve or that depth did not increase for the gold piece as you cranked in the higher frequencies. In the case of the gold piece, you might find that the 26 khz is optimal. Who knows.

You should try some of these tests in gold field mode too.

Also note there is no ID Normalization with the HF coil.

 

[CharlesUpstateNY]

Yeah those were my LF coil settings I posted above by mistake. Below are the HF settings I ran today. I dug a deep nickel today (14kHz) which impressed me depth wise. It was also tipped half on edge and sounded pretty small as I swept it.

I tested several dozen coins and trash targets yesterday at all 3 frequencies 14/28/54 and printed off a pocket field guide for my hunt today.

Today's loot was an earring, 10 Euro Cent, brass Carwash token, deep nickel. Also dug a couple foils, 2 zipper pulls, a small brass what's it, and 2 small brass keys. The keys were deep and still had the half rusted ring, that was one jumping around weird signal.

I also tried tracking GB today, it was more unstable but maintained a lower GB number vs pumping/manual. I could hear the ground but then I'm used to that on my Explorer so I left it on tracking.

Notch 00-00
Disc 10
Full Tones
Sens 90
TX Power 2
Frequency 14kHz
Iron Volume 1
Reactivity 2
Silencer 1
Audio Response 4
Audio Overload 1
ID Normalization N/A

 

[vferrari]

If your soil is mild, surprised it was chatty in tracking. You can try adding a little ground notch. Is/was the mineralization bargraph present or fluctuating there?

 

[smokeythecat]

I dug one of those tungsten or titanium or whatever they are black wedding rings, a very old one, down almost a foot. I almost decided not to dig it, but I did anyway. That was in salt laden sand.