Etrac and small gold

[ZincolnDigr]

I noticed in bench testing that my Etrac misses some small gold jewelry. I have a small gold cross and my wife's gold herringbone necklace. Not a peep on either one, and the herringbone necklace in not that small. My DFX sees them with no problem? Why is that? I assumed that the FBS technology touting 1.5kHz - 100kHz would have no problem with small gold jewelry??? Any ideas? I am not trying to start an Etrac bashing thread, but this really disappoints me. Not everyone has "deep silver" to look for!

 

[coinnut]

Hi, what program are you running? Try the Minelab programs - Relic and see if it still misses it. You may have those numbers for gold edited out. I think they would run in the pull tab or foil range. If your selected program discriminates the junk, it may disc out the gold. Just a thought.

 

[ZincolnDigr]

Sorry! Forgot to mention that this was in all metal. Thanks for the hint though!

 

[Beachcomber]

There is a lot of small gold items that can not be seen with FBS detectors be it an Explorer or an E-Trac. You would think that because it supposedly goes to 100khz that it could see small gold but there must be so many compromises going on within the detector so that it can cover that range that it actually losses the ability to see small gold. Any single frequency machine running in the 50-70khz range can see gold so tiny that you need a 10x loupe to see it so you would think that a detector that goes to 100khz could easily see small gold jewelry but that has not turned out to be the case with FBS Technology. Still the FBS technology does see smaller gold than most machines can when operated in the saltwater environment. With most single frequency VLF machines you need to use the discrimination control to cancel out the effect of saltwater. The level of discrimination needed to eliminate the effect of saltwater also eliminates even more gold than that of the FBS Technology. Still I wouldn't mind of the Explorer's and E-Tracs could see smaller gold. Also keep in mind that when detecting a chain a detector is detecting individual links of the chain not the chain as a whole so unless the chain has some fairly substantial links, a medallion on it, or a large clasp there is a good chance it will not be detected. JMHO

HH

Beachcomber

 

[David]

Hi ZincolnDigr, I posted this on another thread but it is very relevant here and answers your questions, have a look. When it is said below that FBS and BBS units cannot find small nuggets or tiny nuggets that is the same thing as they cannot find small very fine jewlery. And when a Sovereign GT(BBS) is referred to, the same can be applied to a FBS machine.

Beachcomber, very good explaination and I just read your post twice. I do wonder if the very poor discriminating Pulse Induction units will see small gold better than the FBS and BBS units on wet saltwater sand -- environment at the beach ??

If anyone has a Minelab Product Catalog look on page 11, then look up on that page, it says, "Have You Tried the SD Series on the beach? They go DEEP!" CoilTek makes a whole series of salt coils or some call them anti-interference coils for the Minelab SD, GP and GPX PI machines . Made for hunting salt lakes and under-near power lines. They are advertised as only about 5% less than a DD coil. A better choice than a DD at the wet sand saltwater beach I would think and they might out-do a FBS--BBS unit for depth in the wet saltwater sand but then again very poor discrimination. The new GPX 4500 is suppose to have better discrimination than past units though.


http://www.findmall.com/read.php?63,847731

Yes BBS(Sovereign) and FBS(Explorer and E-Trac) will find gold in the goldfields but Minelab does not recommend them for prospecting for gold(look on their web site and they are not listed on there under the heading of Gold Detectors(even though the Sovereign GT in Auto Trac in All Metal works very good on the goldfields soils) because THEY WILL NOT FIND SMALL MICRON GOLD like 1/10 of a gram or so, only for bigger sized nuggets, so they are not listed as goldfield detectors. If you want to find about 1/2 gram or larger they will work fine.
http://www.minelab.com/consumer/page.php?section=126


Quote, "If you don

 

[Beachcomber]

Actually PI's work on a totally different principle than a VLF or FBS machine. Their sensitivity to gold comes marginally from the frequency that they operate with most being under 10khz an more importantly from the Pulse Delay which is the point at which the receiver is turned on. The shorter this delay the more sensitive to small gold a PI becomes. Even PI's have thier problems and most can not see gold as small as a VLF or FBS machine though they are very closer to an FBS machines gold capabilities than they are to a medium to high frequency VLF when it comes to small gold. To see really small gold a PI's Pulse Delay needs to be down around 10us. Only the best PI's can achieve this. Most bottom out around 15us which keeps them out of the range of the really small gold and thinner gold chains. Even the PI's that can go down to 10us are not able to use that capability around saltwater. At a pulse delay of 10us a PI detects saltwater so the pulse delay needs to be raised to eliminate saltwater which requires a setting in the 13-15us range again cutting into the PI's abilities in the area of small gold. There is no perfect detector for all situations or all targets. The single frequency VLF's that can see gold chains and other very small pieces of gold are pretty much useless in and around the saltwater but will work great up in the dry sand at the beach. As I said nothings perfect. You just have to find what works best for the type of hunting you do. If you like different types of detecting you will usually end up with two or more detectors. JMHO

HH

Beachcomber

 

[ZincolnDigr]

Thanks for all the input guys! I mostly hunt newer parks, and my big "treasure" opportunities are gold jewelry. I have little chance of finding silver. I like the Etrac alot more than the SE for my type of hunting. The SE is too slow for my taste in modern trash, and not very easy to separate the possible gold jewelry from the pull tabs like the Etrac. I have relatives that I plan to visit now and then that have older land that I can hunt, so I like the deep silver ability that the Etrac offers. I guess I can't have it all!

 

[thedeserttortoise]

I'll be doing a small test with some fine gold between the Xtera and the Etrac soon. I was just going to use it for my own reference but instead I'll video it in case it helps others too. I'll do a post as soon as possible. I'll be heading out to the goldfields in the next week or two and report back. Tortoise

 

[Beachcomber]

If you have the high and low frequency coils as well as the stock mid-frequency coil it would be interesting to see how much difference there is in sensitivity to fine gold between the 3 individual frequencies compared with the FBS E-Trac. Looking forward to seeing your results!

HH

Beachcomber

 

[thedeserttortoise]

Thats a good suggestion. I do have all the freqs. Consider it about to happen.....

 

[ZincolnDigr]

I re-tested my Etrac tonight on the necklace and small gold cross with one difference, I turned "deep" on. Now it sees both of them! Granted, I am only getting about 1" to 1.5" in air test with my 5" excellerator, but my DFX only gets about 2.5" with it's hotfoot coil. While I know this is not much, at least it sees them now!

 

[thedeserttortoise]

Ive got a couple new coils coming for the Etrac. A WOT, an SEF, and a 6" dd. For the Xterra I have a 6"dd, all the cc's (3), and the elipitical dd. I just got a few of my friends together to help and we are going for it by next Wed if all works out. I'll be in the Copper Flats area by Hillsbourgh NM. Very active digs. I'm taking my sluice too. I promised to make a video for the guy in California that designed my new header box on the sluice. Should be a fun couple of days.

 

[Beachcomber]

n/t