Impact in the goldfields?

[PhaseTech]

I thought I posted this here, but can't seem to find it?
So I'll say it's a repost just in case :8

While up in the goldfields earlier this week I tried the Impact on a trashy spot. I used the stock 11x7" coil in the All-metal Gen mode and 20 kHz. I was very impressed at how well it ran.

I was in "warmish" mineralisation. Mild sandy wash, but with various sized hot rocks. It was where a forest track cuts across a creek/gully. This particular junction has quite a bit of trash, so I just detected along ignoring any very low numbers. Most targets dug were non-ferrous. I got fooled on one large bit of wire that was sitting upright. I dug about 4 hot rocks that were a very faint but good sounding signal, but not strong enough to register any ID on the screen. The most impressive dig was a nice clear hit ID of 35, and I dug down and it was a small round seal off a juice bottle, which was sitting on it's edge. No gold, but Zed's have cleaned up all the fainter signals in this spot so no surprises there. My settings were Sens 66-72 and iSat on 6. I wasn't using Tracking, so was re-ground balancing using the trigger.

I've done some tests using the smaller 7.5" elliptical in 20 kHz, against the Fors Gold+ (19 kHz) with the 5" coil, and there really isn't much in it. The Gold+ has a little bit more aggressive sound to it, but the Impact is smoother, sounds pretty much like an older wiser Gold Racer :tongue:

The threshold and tone adjustments steps in the Impact are spot on - two features I rate very highly for a unit to be taken seriously as a gold machine. It's really looking to be an excellent all-rounder.

 

[oldtimerROB]

Hi Nenad, where are you now? in SA. Wait till you bring it to the GT in very high mineralisation; I hope you will be even more impressed.I posted this information out on this forum 2 months ago but no one believed me and some even ridiculed me for buying the Impact-no class people.Hope they believe you and we can get the ball rolling on the Impact.
I have some questions..... 1/ In GEN mode the default setting for threshold is 55 but sounded a little too loud with earphones,so I reduced it to 45.You mentioned it was spot on,so am I doing the right thing? Could I be missing nuggets? If using it without earphones 55 threshold sounded faint because the speaker is under the housing.In fact I had to increase the audio enhance feature to 5,its max. because I forgot the jack adapter at home and could not use the earphones. 2/ You seem to prefer using the ID display to identify your target but in very high mineralisation I found the display useless because it was jumping all over the place so I go by tones alone.I set the disc. very low in GEN Mode and hear low tones for iron/hot rocks and high tones for everything else.I looked at the Nokta Gold+ manual and it did not mention this feature so is only a one tone all metal mode? Its fun identifying hot rocks before you dig them up but I dig them up just the same to be certain.As gold is close to iron could I be missing nuggets using any form of discrimination? 3/ What do you think about using DI3 mode and turning disc. from 03 to 00 to look for nuggets? would this work on our goldfields? 4/ I have been using auto GB only and once I got a false signal due to ground changes but I GB every 10 minutes or so.Tracking mode is for use in GEN mode only,so would I be better using it? 5/ Steve Herchenbach has identified a problem setting the audio knob to full volume.After 80% full volume the overload volume starts to diminish and reaches a very low amount at 100% and an overload warning comes up.It only happens when the mineralisation meter shows 100% but I don,t always look at it.So you could miss a large object at very shallow depth and assume it is extreme mineralisation.I would recommend setting it around 90%. Regards,Rob.

 

[PhaseTech]

Hi Rob,

Haven't been to VIC since before christmas unfortunately.

We've got a good variety of ground here in SA, very mild to super hot.

1. Your threshold level depends on what you are using, type of headphones, your hearing, and to some extent your volume level. Have you noticed that the threshold seems to get louder as you increase you iSat? I think Volume one notch off max., threshold 45, and iSat 6 is about spot on if using headphones. And then make fine tweaks as necessary. I would never use the speaker if hunting for gold - and that's with most machines.....unless it's really hot and I'm using a booster coupled to a GME speaker up on my shoulder strap. The 5 levels of boost are great, but I'd only ever engage boost when checking a suspected signal. If you leave boost on all the time you will have a twitchy machine. But in very low mineral ground, I wouldn't hesitate using Boost2 or even 3 as the lift you get on a soft signal is quite noticeable. If you forget your headphones, turn the threshold to 50 and iSat to 8 and that should give your plenty of volume, but you may have to take your control box cover off.

2. No, if trash levels are not too bad I dig everything. Because you have a nice ID right in front of you, you can't help but to see the number coming up, so I will try and take note. Yes, as mineralisation levels increase, target ID accuracy will suffer and that's with any machine. Reducing the sensitivity can help, but you are sort of sacrificing target sensitivity for ID accuracy. Yes the Fors Gold+ does have the readout active in the GEN all-metal mode but there is no adjustable Disc or ID Mask as it is called on the Fors. So all targets have the same tone. On the Impact being able to adjust the Disc in all-metal is essentially a tone-break adjustment, because it doesn't actually disc the target out, but it's an awesome feature.

If you want the Impact to grunt on shallow iron, but signal all deeper targets the same, give GEN(D) mode a try. I actually prefer the Gen D grunt compared to Gen mode. The actual grunt sound is a little deeper compared to the normal tone (which isn't adjustable in Gen D). So basically Gen mode has an adjustable tone, with an adjustable Disc level which essentially sets your tone break. Gen D mode has a high tone and a low grunt with an adjustable break point, but won't grunt on iron targets that are deeply buried. This is the same as how the Iron Reject circuit is implemented on the Minelab VLF's like the Eureka Gold, XT17000 etc.

3. DI3 is just a three tone fast recovery mode. It won't go as deep as GEN or DI2. The only time I'd consider using it is if you were in a spot with a lot of shallow zippy hot rocks, or a high trash area. But DI2 would generally be my preference, due to better depth. A small deep target just hits a lot nicer.

4. If you are not using tracking, you should be re-balancing a lot more often! I'd do it every minute or so, particularly early in the hunt to gauge how variable the ground is.

5. Had to read this one a number of times before I figured out what you were saying. Yes on full volume the overload "whistle" is a bit quieter, but I actually think this is a good thing! It does the same even with the Mineral meter on minimum. On a 1 inch rusty screw I get no overload even rubbing the coil. If I do get overload I simply raise the coil a little.

Best of luck out there.

Nenad

 

[oldtimerROB]

HI Nenad, Its still too wet and cold to go hard core camping/detecting in Victoria and waiting for sunny weather and minimum overnight temperatures above 5 degrees. Thanks for your detailed reply regarding the Impact.Its very much appreciated being able to discuss the Impact on this forum as you are the only other one who has tested it in a goldfield.That includes the USA.
Regarding the audio boost,your comments are spot on.I asked you that question because I saw a video on youtube put out by Apulia Detecting.In it he made a test on a
one gram and a sub gram small pieces of natural gold in medium mineralisation soil.His test showed that without audio boost in GEN mode he got faint signals at 4 inches for the 1 gram and 2 inches for the sub gram using 20 Khz.When he turned audio boost up to 5 he got much stronger signals,so he is using this setting in general search mode.I can only use that setting near where I live South of Ballarat as the soil here is mainly low mineralisation around Durham Lead and Napoleons.Also he uses audio tone reduced from 33 down to 15 when searching for natural gold. So wondering if audio tone of 15 will be better? Just trying to tweak the Impact for the best possible performance on nuggets.
Regarding the GEN D mode I have never used it as I read in the manual that deeper iron and gold/non ferrous give the same tone but only grunts on shallow iron/hot rocks.As I have scoliosis in my back I try and limit too much "digging up all targets" as it severely limits how long I can detect all day-usually 3 hours max. I had intended using the disc. modes to save digging (one of the reasons I bought the Impact) but quickly found out I got too many false signals from the small patches of extreme mineralisation we have here ( mineralisation 100% on the meter).Besides I don't feel comfortable detecting in silent mode as I have been using a VLF since 1980 with threshold.
Every time I turn on the Impact I will now have to change a fair amount of settings so I think I will start using the "save" feature.Hope it works.
Best of luck with your detecting and have a good one.Regards,Rob.

 

[oldtimerROB]

Went out yesterday to a surfaced area south of Maryborough where 37 years ago me mate found a 1 kg. nugget.Dug 70 holes and found nothing.If anything I am getting lots of exercise at 72 but clearly I can see I am chasing rainbows with the all metal mode.Camped out and it was minus something overnight.GT true to form. Saw a squashed steel drink can on the ground near this surfacing and it registered fairly loud at a puny 12 inches in air and then got weaker. Switched to DEEP mode and it registered loud at a more respectable 24 inches.Buried a 1.5 inch diameter ball of chocolate foil in red clay in the middle of the surfaced area in an 8 inch hole and compacted the soil.GEN gave a decent shrill signal.Deep was getting a strong signal 12 inches above the ground. After that saw it was no contest.