Sweep speed

[tvr]

I should probably spend more time on this forum than I do. Got a day trip to the beach yesterday (2.5 hour drive each way), took the Excal and got a piece of gold ... the rest of the story was other observations.

Now the sweep speed thing, I was wandering the beach dry and wet and over the dry spotted a small foil ball sitting on top of the sand. I swept the coil over it and nothing. The foil ball was about dried navy bean size so I expected to get a sound off. Detector was in discriminate more with the discriminator at minimum, just so it nulls on iron. Since my normal sweep is what I consider a relaxed, kind of slow sweep of about one second on a 3.5 foot sweep left and the same going right, I picked the speed up a little and nothing. I slowed the speed down a lot and the foil started coming through clearly as a nice low tone that screams dig me. The sweep speed where the foil came through clearly with the Excal is about where I slow my CZ's down to make sure a signal breaking high tone isn't a bounce on a nail ... and that is slow, about two seconds on a two foot sweep to the left and another two seconds on the 2 foot sweep to the right; about a four second total cycle time for one narrowed sweep.

I know I sweep slower in the water than when out, probably closer to this slowed down, out of water sweep that did hit on the foil ball.

How critical have you all found sweep speed to finding good targets like small thin rings and medium to thin chains?
tvr

 

[bootyhoundpa]

it seems that sweep speed can vary alot ..... the area being hunted will often dictate sweep speed depending on amount of trash and mineralization resistance.....ive hunted a colonial homesite where the best combo was gt with 15in wot coil..it was best at hitting on the old flat buttons....10in coil just wouldnt give as clean of a signal...and these buttons were not deep either ,only 3-4 inches deep.... ive used the gt wot combo at the beach -usually with great results but last january i was at the beach with it and couldnt get a clean signal with it ..broke out the excal and started hitting deep coins right and left...... as far as little pieces of foil goes missing a few pieces of trash aint gonna break my heart but if your missing the foil you could be missing the small gold..... i never found a gold chain with my gt or excal but i did twice find very fine silver chains...one of the silver chains i would prably not have found but i got lucky and rested the coil on the sand to make an adjustment and it stated chirping....ive done feild test at home with a gold chain -not with good results ..machine usually nulls and im one of those that refuses to hunt in all metal.. i have found plenty of small gold with the excal....and much like you mentioned you have to adjust your sweep speed to the targets demands not your own....i did find a small childs ring last week and large earing -both 14k and the ring was a good solid hit the earing not as good a hit-both in water so im not sure of depth....i did some experiments at home and found that the 14k earing did not even move the meter on my whites machine which had i been using that machine and going by vdi i would not have dug it.....

 

[Critterhunter]

The fact that the foil was on top of the ground could have been the problem. I've had a few times with my Explorers where I laid a coin on the ground and could only muster about 3" in air testing over it. I think these Minelabs some times get confused and start thinking the air is where the target should be and the coin on top of the ground is the ground load and it should be ignored. As far as gold rings gold, even super thin plain ones will hit hard on the GT. The fact that they are an intact circle makes them hit hard even though they are super thin. Other machines are of course more sensitive to things like fine gold chains but that has the drawback of banging hard on bits of foil and such. I owned machines like that and they were too noisey for my tastes on land for that reason. I'd rather ignore the small stuff, as most of what's lost is probably gold rings anyway, and ain't nothing as deep as a Minelab on a gold ring for the most part in terms of a VLF discriminating detector.

 

[Tseeker]

How do you account for the excal being able to get hits when your sov. could not? I thought they were essentially the same machine except the excal is waterproofed.

 

[Critterhunter]

Perhaps a smaller coil that is more sensitive to smaller items? Everything I've ever read says the GT is a bit deeper and even more sensitive to smaller stuff that prior Sovereigns. I know at least some Excals were based on the XS Sovereign, but don't know if the new Excals are using GT electronics in them or still an older Sovereign?

 

[bootyhoundpa]

in response to t-seekers ?... why would the excall see signals the gt did not??? the only thing i can figure is i was using the 15in wot coil on the gt that day and there may have been deep iron on that beach causing masking that didnt have the same effect on my excal with the 10in coil... ive wondered the same thing...that beach did not like the wot coil..... masking is three dimensional...i believe masking can also come from below good targets as well as side to side....

 

[tvr]

See picture for size comparison. Foil looks like wrapper foil and is pretty tightly wadded up; as I found it on the sand surface.

I went out in the yard an did a little bit of testing. I have no intent to turn this thread into a detector comparison, but I know the CZ's well and am working on learning the Excal.

Put the ball on the ground and went with my normal sweep speed with coil about 1 to 2 inches off the soil. CZ6A with 12.5 inch coil hit it with a scratchy double blip as each side of the coil went past the target. CZ20 with 8 inch coil hit it with fairly solid sounding single blip at the center of the sweep. Excal with 10 inch tornado coil on it did not pick it up until I slowed the sweep down; then with the slow sweep it was rock solid and sweet sounding. I ripped the foil ball in half, wadded it back up and tried it again. CZ6a with big coil did not hit it until I went to all-metal and then, if there were back ground wave noise, I wouldn't hear it; a no dig response. CZ20 got a scratchy hit about one in every 3 sweeps; probably not dig but maybe. Excal hit with a scratchy very low tone when swung very slow, but hit on nearly every sweep; I'd dig that. An increase in coil speed and it was lost. I would not find the target in the first place do to the swing speed.

Besides getting an indication that smaller coils may pick up smaller targets a little better, I am thinking that approaching the limit of what the Excal will and won't see with metal mass, that coil speed may be more important than with more solid targets like a nice ring.

Have any of you tested chains with an Excal or Sovereign? I haven't done any real chain testing since I got the Excal over a year ago. Should I slow my sweep speed down more or just go for the solid pieces that have more mass? I may need to set up a chain test ... except last fall I sent most of the chains that I had to the refinery for melt.

Thoughts?
Cheers,
tvr

 

[Critterhunter]

There's your problem...14" coil. Even if there was no masking going on if the beach is badly mineralized then targets can easily be washed out with the ground "glare" that a larger coil is taking more of in. Found that to be true with my 15x12 and as a result it got less depth than even my stock 10" Tornado in my soil. Some people even say they get more depth with an 8" coil than a 10" coil due to the amount of ground signal larger coils are taking in and degrading or washing away the target signal with. This is a bigger problem on non-Minelabs, and more of a problem with concentric coils too, but just the same DD coils and Minelabs do suffer from this problem to some extent in the right types of minerals.

Always like to hear detector comparisons on tests and such myself, so thanks for posting that. The 12x10 seems to be a bit more sensitive to tiny stuff than the stock coil for me. Talked to one person who said they tested a gold chain with the S-12 and the 12x10 and the 12x10 hit it good enough to be "dig worthy", but that they would have passed it (must have nulled or something? don't remember what they said) with the S-12. Different coils can give different results of course. In general, for example, small coils will hit harder on small stuff such as say a 5 or 6" coil. Personally I don't care for the machines I've owned that were real sensitive to small gold and thus small bits of foil and such. Too noisy for me because I like to hunt with zero discrimination on a detector and go by tones alone to do my discriminating with my ears, but when you're popping and clicking on tiny bits of foil and other junk that gets old real quick. Way I look at it rings are the most common jewelry probably lost, so that's all I care about myself...And in terms of gold rings even the thinnest small gold ring will bang hard on a Minelab due to it being an intact circle...And at depths that will amaze you.

 

[OldBeechnut]

Test that alum ball in PP mode with senstivity turned up to 10 am...don't you have the remote PP mode? you can swing faster, hit with Hi senstivity, then check in disc mode...do the WiggLe Wiggle over the target once you have seen there is a target to be discrimnated...Off next week, just doing some home repairs..drop me a PM, we can meet for a few moments at your beach...........

 

[Hopster]

I do about 95 percent in water with the excal in discriminate, auto, auto sensitivity.
The water helps slow the sweep, but I listen carefully for threshold changes and resweep slowly when I have a change.
The excalibur in discriminate has a tiny time delay between the detection and the audio output.
Same goes for the threshold changes (low tone to high etc.)
Most people I watch on the beach sweep way too fast. Thats how I picked up half reale coins that others had just gone over.
Hope this is somehow helpful, speaking for the excalibur only here.

 

[tvr]

Yes, this one has the pinpoint mode change and yes in PP it gets a response with a "normal" sweep speed. I have not been hunting the Excal using the reverse discriminate method yet. I'm still running the factory yellow headsets. Have many parts collected to mod or replace the headset, but have not done so yet. Those stock headsets do not isolate wind and wave noise much at all and I find turning up the threshold enough to overcome a lot of background noise has me unconsciously gritting my teeth during a hunt. I finish hunting with a sore jaw. So, I am mostly hunting in discriminate mode with the discriminator at minimum. I really need to do some upgrading on the headset.