Small coil techniques?

[detectorbase]

Hello All

I just received my SunRay 5". I normally hunt with the SunRay 8", but wanted something a little smaller for the trash.

My question... does anyone have any special tips or techniques with the small coil? I found myself digging 'smaller' items, I also noticed the overload tone on surface finds. For instance it was overloading on a key, which I thought was weird. I was able to pull a 1943 S War Nickel with it, but overall, I seem to have more success with the 8"... but I just started with this.

Any suggestions are greatly appreciated.

Thanks!
DB

 

[jeff & Maria]

I find I can turn the sensitivity up with the smaller coil. Isn't it fun pinpointing with that little coil!

 

[txbluesman]

Don't give up this coil. It takes a little getting used to due to its small size and high sensitivity to small items. I have a nice collection of diamond ear-rings (studs) that I have found with the 5". If you will put in a honest 20 hrs with this coil, 2 think you will be real happy that you made the purchase.

PS. don't get in a hurry, swing this coil slow...

 

[Des Dunne]

DB,

"Txbluesman", has it right...Low AND Slow is the way to go with a small coil AND, the smaller it is the slower you go!

On your [Overload] Q:
Typically, a detector with this feature will overload because:

1. The target is too close to the coil
2. The target is too big
3. The detector cannot classify the [large] target correctly

However, the answer to your Q. is coil windings - essentially the size of the windings.

In your 5" Double D coil the internal windings are probably 4.5" from coil toe to heel.
There are two windings which overlap in the center of the coil.
The area of overlap is probably almost four inches from end to end and I'm guessing here, about an inch in diameter.
The size of your key was probably no more than two inches in length.
You mentioned surface finds so I'm assuming "the key" was on the surface?
So the 2" target was too close to the probable 4" elliptically shaped overlap area so it resulted in a large detection.
That probably would not overload a similarly sized concentric coil?
Neither should a 2" surface target overload a 10" coil.

Forgive my ramblings here but you asked a GOOD question and I offer [my] explanation!

Good Hunting

Des Dunne
Minelab

 

[detectorbase]

Great explanation. The key was just below the surface. Was not visible, but a couple scrapes of the ground popped it out.. so basically it could have been laying on top.

Because of this, I was curious of signal tone alteration between the coils? If I get a overload on a surface key, what will the difference be with a penny 4" under the ground? Basically same tone and signal as with my 8". Fainter? What would a half dollar sound 4" under the ground? Overload?

Thanks!
DB

 

[Dan-Pa.]

Basically small coils overload quicker...Hope there wasn't a 57 chevy buried under the key...I would use fast and boost my sens. up a bit..
Just kidding about the chevy but indeed object under or around original target can cause an overload..Like everything else takes time to adjust to so give it a chance...Certainly a must next to iron fences, playground equipment, sidewalks with rebar in them and just areas where large coils won't fit..Certainly easier to handle weight wise and may improve your swing technique as you will learn to overlap with a small coil....

 

[detectorbase]

So does everyone boost their sensitivity up when they go with the smaller coil?

I currently run in AM/Ferrous with sensitivity around 21-22 with the 8".

Thanks!
DB

 

[Des Dunne]

DB,

Personally, I prefer small coils over big coils.
Anything over 8" is a big coil!
Anybody can go out and make great finds with "a big coil", BUT, it takes real skill to winkle out great finds with a small coil!

Did you know that with a small coil your Explorer can show you when two targets are on top of each other (as in the case of a junk target a few inches above a coin/ring) or overlapping, as in the case of two coins buried together?
Watch the cursor for tiny minute movements after landing on a spot that the FER and COND cross references have selected.

Small coil technique:

1. Search slowly
2. Reduce Sensitivity (not increase)
3. Overlap sweeps
4. After hearing more than one target in a sweep search a "4" square" area around the targets very carefully in straight lines AND in circles as if cleaning windows!
5. Switch to pin point and "isolate" the targets.
6. Use All-Metal and if you have a meter ID system check it visually.
7. Slowly raise the coil up and detect "away and upwards" to check depth - if still loud = shallow etc.

On the sweep speed, with a coil as small as five or six inches and, if you just know that there are coins/rings to be found, search very slowly - 1 foot per 5 seconds and, as I indicated, with a lower sensitivity.
You can progressively increase Sensitivity as you go but with too high a sens level some false detections (which may be distracting) can occur.

Good Hunting

Des Dunne
Minelab

 

[detectorbase]

This is great. You say lower sensitivity? Where should sensitivity be? The highest point before instability (chatty beeps) or lower than that? What is a good bench mark for sensitivity settings?

Thanks!
DB

 

[Dan-Pa.]

Basically your call if you want extra depth higher sens is usually possible with a smaller coil...If your in a trashy area or want to hunt near an iron fence, playground equipment or the like might want to lower it..No set answer remember an Explorer is a tool and your sort of the nut behind the wheel so your call...

 

[James N.D.]

I tried the Sunray X-5 at a Fairgrounds in Minnesota. With the first Half Sweep of the Coil, I got a Good Signal at 6" and I had previously searched this area with the Stock 10.5" Coil and also the 5X10 Joey Coil, anyways, I dug a plug and pulled the plug out and at the bottom of the hole was a Silver Quarter. I was shocked! I then dug a few Wheat Pennies in other area's that I had previously search also. Great Coil I think! So a Coin at 4" will give a nice repeatable signal unless of course there is a lot of Trash or Iron present. Then you will most likely get a choppy signal, but there should be enough of a signal that tells you that it is a target to dig. A Half Dollar might overload still if only an Inch Deep but I could be wrong. Good to hear you found something good already and Good Luck and HH!

 

[txbluesman]

I typically run my X5 at Sensitivity 18, Fast ON, All Metal and either Conduct or Ferrous depending the amount of iron present. When I'm in a real trashy vacant lot, I will usually reduce Sens to 12-15. My focus is not depth but rather target seperation. And as Des stated, slow down that swing speed and those previously masked targets will start revealing themselves. I'm amazed how many holes that I have dug where I recovered two targets, one good and one bad. Happy Hunting

p.s. Des, your small coil techniques post was excellent!

 

[Sulli500]

Was wondering if the SE Koss headphone would work on xl 32ohms
into 100 ohms.

 

[savage]

Greetings detectorbase,
When I first got my 5" coil it took a little getting used to. I found that I was swinging way to fast. I guess the machine being a bunch liter and wanting to cover more ground faster. I set my sensititvy at 17, deep on, all metal. I found that the key was to sweep slow and listen for those different tones.

Savage

 

[detectorbase]

[quote savage]Greetings detectorbase,
When I first got my 5" coil it took a little getting used to. I found that I was swinging way to fast. I guess the machine being a bunch liter and wanting to cover more ground faster. I set my sensititvy at 17, deep on, all metal. I found that the key was to sweep slow and listen for those different tones.

Savage[/quote]

So do you go with 'Deep On' w/5" and trashy area?

DB