HF Coils and Gold Coins - Discussion

[CZconnoisseur]

So I've lived in Colorado for over 2 years now, and have dug hundreds of deep (6-10") coins from several local spots in that time. The conventional approach to deep coin hunting in this environment has been using 4kHz with the 11" coil, which helps get through the mineralization and ID iron for what it is....seems like the higher frequencies will sometimes get fooled by deeper iron....but I tend to dig it out anyway.

Mike and I have hunted several parks into oblivion, however, we still manage to get fantastic old coins about 50% of the time now, whereas when he and I started we would regularly pull 5-8 old coins per hunt EACH. The last several hunts the finds have dwindled somewhat, but not to the point of calling these areas "hunted out"...quite the contrary - we now have softer, cooler ground to hunt and need to check those less-hunted areas that are diggable now.

I've been wondering about the new 9" HF coil in these heavily-hunted areas specifically for gold coins, namely the $2.50 and $5.00 gold coins. I've always (who else hasn't?) wanted to find just one of these among the deep Indian cents and occasional Barber dime - the era is correct for gold coins since most of what we find was dropped from 1880-1920 when many gold coins circulated. What makes it more likely is that fact that Colorado is midway between San Francisco and the rest of the country - even moreso around the year 1900, and "S"-mint coins commonly circulated around that time (Mike and I can PROVE IT!!!!)

Would a $2.50 gold piece, which is almost the same measurements as a US dime, sink further into the ground over the course of ~120 years vs a silver coin? The HF coils should be "all over" a low-conducting target like this. I can't seem to locate any coins below the 10" mark...and most of what's been recently found in the parks is almost always between 8-9" down. I know gold coins HAVE TO be present, I just wonder if they're just out of detecting range at the moment....

I would expect the HF coils to be slightly less sensitive to a deep silver dime, but if it's at least as good as the 11" coil on a similar target....AND ignores iron a little better at depth, then it's a no-brainer.

Has anyone here used a HF coil in a "Hammered Park" setting (for deeper, older coins) and have a story to tell?

Even in 4kHz, the 11" coil on EVERY HUNT finds deep beavertails, Bic lighter strike wheels, pieces and whole ring pulls, and foil...everyone's favorite!!! It's time to step outside of what is working and see if there's a little more to be had at the next level down....

 

[Architex]

Reactivity at 0 helps, along with the other stuff you probably know about.

 

[squirrel1]

Well, if you have been hunting your parks using 4khz,,,You can bet you have left dapper nickels behind.
You have also possibly left some higher conductive coins behind,,,due to separation issues with iron running 4khz.

The round HF coil will jump on a nickle big time in 28.8khz and 54khz big time.
The elliptical will too, just not as deep usually.

My suggestion would be,,,go to park, wherever the highest concentration of iron,,,put elliptical in there at 28.8khz Reactivty 2.5 for starters.

Lower conductive,,smaller coins,,soil masking will hinder LF coils moreso vs HF coils.

 

[enderman]

The 11" LF coil @18kHz is no slouch on nickles either, even the 12kHz hits lots.

I've got more old nickles with the 11" Deus then any other machine. Real nickle too, not the easier to hit copper-nickles.

Honestly I couldn't imagine running a site in 4kHz alone, that would be after it's hit hard with 12kHz and 18kHz.

I know this discussion is about the HF coils, but I thought it was important to mention.
In the meantime go back and hit it in 18kHz and 12kHz, there's all kinds of stuff there I bet. 4kHz is difficult to use IMO, relative to the 12kHz and 18kHz.

Higher Freqs won't have you chasing deep waterfalls like 4 does. My old sites have a lot of deep iron so 4kHz is kinda distracting when looking for smaller coin sized targets.

11" LF @ 18" will hit a small 14K ring way past 16" in air, 9" almost as far. More Freq might not be better, it's all about hitting the right spot on the curve for a specific target.

I don't find myself being fooled by iron with 12kHz or 18kHz in a site with sufficient targets. I dig very little unintentional iron with the Deus in the high Freqs.

If I was looking for that gold coin I might run the lowest Freq possible on the HF coil, unless at least a quick bench proved otherwise. I would bump the Freq up until I lost depth on a gold coin or pseudo gold coin.

 

[squirrel1]

The 11" LF coil @18kHz is no slouch on nickles either, even the 12kHz hits lots.

I've got more old nickles with the 11" Deus then any other machine. Real nickle too, not the easier to hit copper-nickles.

Honestly I couldn't imagine running a site in 4kHz alone, that would be after it's hit hard with 12kHz and 18kHz.

I know this discussion is about the HF coils, but I thought it was important to mention.
In the meantime go back and hit it in 18kHz and 12kHz, there's all kinds of stuff there I bet. 4kHz is difficult to use IMO, relative to the 12kHz and 18kHz.

Higher Freqs won't have you chasing deep waterfalls like 4 does. My old sites have a lot of deep iron so 4kHz is kinda distracting when looking for smaller coin sized targets.

11" LF @ 18" will hit a small 14K ring way past 16" in air, 9" almost as far. More Freq might not be better, it's all about hitting the right spot on the curve for a specific target.

I don't find myself being fooled by iron with 12kHz or 18kHz in a site with sufficient targets. I dig very little unintentional iron with the Deus in the high Freqs.

If I was looking for that gold coin I might run the lowest Freq possible on the HF coil, unless at least a quick bench proved otherwise. I would bump the Freq up until I lost depth on a gold coin or pseudo gold coin.

As far as HF coils both the round and the elliptical.
I don't have mild soil.
My soil medium mineralized.

Using 28.8khz on both coils,,,seems to hit nickels better vs 14.4khz.
Punches the dirt better.
Even hits on deep high conductors better too.

Air test would not reveal this so much.
But in ground targets both disturbed and undisturbed different ballgame.

 

[enderman]

Good to know, thanks.

EDIT: Looking at my chart from the other day, I can see a trend in that direction.

The higher Freqs is allowing a faster reactivity for a given depth. In air of course.

 

[Charles (Upstate NY)]

I air tested $1 $2.5 and $5 gold coins last weekend with my new 9 inch HF coil and wasn't impressed with the depth. Had reactivity at 2. That said in a field test the next day I dug a solid no question signal and found corroded nickel about 8 inches down, was using 14kHz. Maybe I'll take the gold coins out again and spend some time tweaking for max depth and see what I come up with.

As for targets sinking, yes a gold coin will sink faster than a silver dime if soil conditions allow it. Coins get deep by sinking in sopping wet soil, years of grass growing over the top of them adds soil layers from above, and fill dirt spread over top of them. I once recovered a womans gold class ring lost at a house while she was baby sitting. It was lost for 25 years, it had sunk 4 inches.