Is my 1500 working correctly?

[Stingraymb]

I bought a used 1500 on Ebay recently. It was in very clean condition and reportedly "only driven to church by a little old lady on a few Sundays." It has the stock white coil (vs the molded epoxy coil). Per reviewing some old posts, I've been running it on coins at sensitivity 7.5.

I've taken it out 4-5 times and I don't have near as many hours on it as my 250. During Pinpointing - I try to "align" the target as close as possible.
Several times pinpointing on the SAME object I will get around a nickle indicator at 12 inches w/ "c" size, penny at 5 inches "b" size, move the coil away and re-pinpoint it comes up with a different reading, depth, metal content, and size each time.

For coins near the surface - a lot of times it will read max depth and "d' size. The signal is "hot," so I know it's near the surface and try to raise the coil high off of the ground (sometimes it works, somtimes it doesn't) to zero in on a coin.

I found a few dimes which register as pennys and pennys which register below pennys = about 3 inches in clay soil.

I've been digging all "b" size targets and several "c" and "a" size targets to see what's going on. All of the "c's" so far were trash. A few of the "a's" were coins. Almost all of the 'b's coins. All of the above at less than 5 inches.

Right now I feel like I can take my 250 and "smoke" any user w/the 1500 if it's performance (and user experience)is the same as me and my 1500. I don't know if it's my knowledge level using the 1500 isn't up to speed yet, I have a defective 1500, or if it's performing per design limitations.

My 250 flaked out about a month ago and I sent it to Garrett to be repaired. When it came back it seemed to be really "tuned up" performing much better than it was new - maybe the 1500 needs to see the doctor or I just need to log more hours?

MB

 

[John-Edmonton]

It sounds like you might be retuning the machine over the target, and therefore getting different depth/size readings. Retuning is a great way to pinpoint a little easier, but puts the ID out of wack. Also, the 1500 has a bit of a learning curve to it. You have to be dead center over a target to get the best accuracy. Do some quick air tests and see what kind of distance you are getting over a dime and quarter. This should give you an idea if someone has been tinkering with the electronics. It's unusual for the 1500 do give such variations over a target. I'm not sure if its electronics or operator. Keep practicing.

 

[Stingraymb]

I always move the coil away from the target 18 inches or so before pushing the pinpoint and bring it back in.
Air test in coin mode, sensitivity at 7 - Dime 6" - Quarter - 7-1/2"

MB

 

[deerhunter24]

There is a cone effect that is talked about in the manual where the size and depth keep increasing. I always dig those. Many turn out to be coins.

I have had a few times where its right at the top of the surface and is maxed out at size and depth. Usually they tend to coins that are laying vertical or nearly vertical.

IT has been my experience that coins deeper than 5 inches seem to come up much weaker. You really have to move a lot slower for the deeper ones. Also, many old coins come up as "A" size and I have had foreign coins come up as all "A", "B", and "C" size targets. The older beat up Indianheads usually come up as "A" or "C" on my machine. Probably half of them or so. It all depends on where you are searching. If I am in a newer schoolyard (50's and newer), I usually only dig the "B" sized targets. However, old fairgrounds or homes I usually dig a few more oddballs than I normally would cause you never know what you might find lurking around.

Deerhunter24

P.S. I have no idea if that's normal, but my machine does most of the same things that you are describing. If you do send it in to get repairs, please let me know so I can do the same.

 

[John-Edmonton]

The imaging and depth reading probability starts to decrease beyond 6-7 inches. Introduce foreign coins , and imaging/ID can show up nearly anywhere. Another variable to add to the equation is the mineralization in the ground and oxide formation on the coin. I hunt an area, where nearly all the silver coins read in the iron range...and I'm talking about 6 inches deep. When the coin is pulled up, the silver oxide is in layers. The more layers you remove, the shinier it gets, but the information on the coin disappears. A real strange phenomenon.

Just out of curiosity, I air tested my GTI 1500 (new 9.5 stock imaging coil) today after work, and here are my results in zero discrimination:


Clad Quarter:Strong Repeatable signal till 10 inches 0n 100%
Strong Repeatable signal till 7 inches on 75%

Clad Dime: Strong Repeatable signal till 8.5 inches on 100%
Strong Repeatable signal till 6.5 inches on 75%

Although just a guideline, it might me interesting to compare results if you purchased used machine. There might very well be some problems with the machine if your results vary from mine considerably.

 

[Uncle Willy]

There is a bit of a learning curve with the 1500, especially learning it's quirks. Tape some coins of different size and denomination to the back of a big piece of cardboard and lay it down where there is no metal under it and practice locating and pinpointing the coins. Use some small sharp object to probe through the cardboard to see if you have centered and pinpointed the coin. Centering the target correctly is crucial with the imaging coil for accurate readings.

Bill

 

[Stingraymb]

Hey John,

On Zero Disc. air test I'm at the following:

Clad Quarter: Strong Repeatable signal 'til 11.5 inches 0n 100%
Strong Repeatable signal 'til 8 inches on 75%

Clad Dime: Strong Repeatable signal 'til 10 inches on 100%
Strong Repeatable signal 'til 7 inches on 75%

At the 100% max distance above, the indicator is 1-2 notches below penny. At 1.5 to 2 inches closer, it ID's in the coin range. At 75% it ID's correctly at max. distance.

Sounds like my machine is performing at about the same level (slightly better) re. distance as yours and the Id'ing is behaving largely the same as Chuck reports. I'll "put some more hours on it" and report back in a month or so as I continue to learn the 1500 language.

 

[John-Edmonton]

It looks like your machine is fine. I am using Canadian coins, so that might make a difference.