9 posts in this topic
What is the very latest Impact firmware as of 6-23-17? Mine should be here sometime next week and before I get started I will download and install the latest firmware but I'd like to be sure which one it actually is as I have seen that there have been many updates of late ( which is a good thing) but I don't want to start to get used to one way and find out that I'm not up to date. Thanks.
By Nokta Detectors
Hello all...I get emails from customers asking for an update on the optional coils and headphones for the Impact.
IM24 Waterproof DD Search Coil 24 x 13 cm (9.5" x 5") and IM40 Waterproof DD Search Coil 40 x 35 cm (15.5'' x 14'') are now in production and have shipped to most of the dealers around the world.
Wireless headphones - test samples have been received by the testers and we are waiting for their feedbacks. If no issues are encountered, we will go to production. Will keep you updated.
I have emailed Dilek the following.
It would be nice if Impact was updated giving the user the choice of which frequency to be used to normalize the Vdi of targets.
For hunting sites with loads of modern trash, it would be nice to be able to run 20khz, yet have the ID geared to 5khZ.
This just one example.
Much like the Rutus Alter 71 does.
By Ricardo P.
I'm still considering acquiring my first metal detector. My main target would be gold nuggets in an area where gold has been mined before for millennia and there are plenty quartzite veins in granite rocks and a good number of small winter creeks. However I would like to also use my detector on nearby beaches and finding coins and relics is also a possibility around here, because of a rich historical background. So I guess I would need a solid all-rounder with could operate on a frequency high enough to make it hot for gold nuggets. It should be priced around the 1.000-1250 mark and I cannot justify a second, specialized metal detector.
I recently looked at the Nokta Impact and got interested. Do you think it would fit the bill? What configuration would be more effective? Or are there other alternatives that you might recommend - like the minelab X-terra 705 (my previous favorite choice)?
By Steve Herschbach
There is a previous thread with a lot of speculation about just what is going on with a couple of the Nokta Impact all metal modes, the Gen(D) and Sta(D) modes. The thought was that they are mixed modes - in other words modes that are running both all metal and disc in parallel.
The speculation garnered attention and we have now been provided this explanation directly from Nokta Software Team Leader Alper Tozan regarding these 2 modes:
''I read a lot of comments about Gen (D) and STA (D) modes in some forums and firstly, I want to thank you about all your positive thoughts. On the other hand, I want to clarify one thing. In some forum discussions, these modes are defined as ‘’mix modes’’. These modes are not mix modes as mix modes typically result from at least two different software algorithms or hardware circuits working at the same time for decision making to discriminate and detect metals. These mix modes also show characteristics of two or more different modes at the same time including handicaps of each signal processing.
Gen (D) mode, on the other hand, is a true threshold based all metal mode with motion that can discriminate metal without needing any other hardware or higher order software process level. So it always behaves like a classical true threshold based all metal mode but with iron tone and tone break.''
Frankly, for me that raises almost as many questions as it answers. Is an all metal mode that discriminates an all metal mode? Is it not instead a different kind of ferrous/non-ferrous discrimination mode? Whatever it is, it is unique, and that's enough for me! So I will do what I normally do and ignore what is going on under the hood and pay attention to just what it is these modes actually achieve by way of useful results in the field. More on that at a later date.
From Nokta Impact Owners Manual, pages 12-13:
Static Mode (STA)
This is a non-motion mode. In other words, the device will generate an audio response when you hold the coil stationary without swinging over the target. The audio response increases in volume as the coil approaches the target. This mode is recommended for larger and deeper metals.
In the STA mode, the device will generate the same audio tone for all metals and it will display the target ID on screen. At the same time, the ID scale will fill up to the right in proportion to the signal strength.
Target ID range is 00-99. 00-40 are ferrous and 41-99 are non-ferrous metals. You can discriminate out all IDs below a certain ID by using the Disc. setting and simply avoid these metals in the field.
When the device detects a discriminated metal, it will not produce an audio response or an ID. However, the ID scale will fill up to the right in proportion to the signal strength.
The threshold in this mode is internal and cannot be adjusted by the user. Changes in the ground and temperature may lead to drifts in the threshold. Threshold drifts will be reflected in the ID scale either in the positive way (right side) or the negative way (left side). The device may emit an audible response in the positive drifts but not in the negative ones. When the threshold drifts, pull the trigger once to retune the detector. Retuning periodically while searching in this mode is recommended.
IMPORTANT! For a more stable operation, try keeping the coil consistently at the same height above the ground where you retuned the detector.
IMPORTANT! If you retune the detector over a target, the threshold will drift to the negative side and the device will no longer detect the target until the detector is retuned. In addition, the depth of the detector will also decrease.
If the drifts are substantial and retuning does not improve the situation, increase the iSAT setting in the Expert Settings to a level where the drifts are eliminated (for detailed information on iSAT please refer to page 24). As the iSAT is increased, the device may detect weaker signals but will not be able to detect the targets anymore if you hold the coil stationary or sweep back and forth over the target. If the drifts still continue frequently, drop the gain to 39, decrease the iSAT and re-ground balance.
Static Delta Mode (STA (D))
In principle, it works the same as the static mode. The difference is that the static delta mode will generate the same tone for ferrous and non-ferrous targets at fringe depths but it will discriminate the shallow ferrous targets by emitting a low iron tone. Also, Disc. setting is not available in this mode.
Please refer to Table 2 at the end of the manual for different settings used in STA and STA (D) modes.
General Search (GEN)
Different than the other modes, this mode features a threshold tone which is continuously heard in the background.
General Search (GEN) mode is used in 2 different ways in the IMPACT: 1) with the Disc. setting disabled at 0 2) with Disc. enabled (non-zero). When the device is first turned on, Disc. setting will be off. When the Disc. is set at 0, the device does not discriminate targets and detects all targets (metals, mineralized rocks etc.). ID of the detected target is shown on the display (except for negative hot rocks) and the same audio tone is provided for all targets. The audio tone increases in pitch as the coil approaches the target. This is the typical All Metal mode found in most detectors.
When using the Disc. Setting in this mode, the device will emit a low ferrous tone for all targets below the Disc. Setting, and a higher tone for all targets above the Disc. setting which changes in pitch as the coil approaches the target. Let's say you set the Disc. to 20. The device will generate a low iron tone for all metals with 0-20 ID and a higher tone for all targets with 21-99 ID. Upon target detection, the threshold will momentarily go silent and only the target audio response will be heard. The duration of the threshold's silence is directly related to the level of the iSAT.
Gain, threshold and iSAT settings in this mode are optimized to provide the best performance on different terrains. You can modify these settings based on ground conditions.
We recommend using the GEN mode when discrimination is not important and not using it in heavy trash areas or areas containing many hot rocks.
Audio Boost in the General Search Mode
This feature is not included in the settings on screen. Boosts the sound of weak signals received from small or deep targets making it easier for you to detect those uncertain targets. It is recommended that audio boost should be used on a temporary or as-needed basis because it will not only boost the target signal audio but it will also boost the volume of ground noise and false signals along with the threshold hum.
Audio Boost consists of 5 levels (b1-b5). At start up, the Audio Boost level is set to low (b1). To increase the Audio Boost level, pull the trigger and press the minus (-) button simultaneously. Audio Boost will only work in the GEN mode.
General Search Delta (GEN (D))
In principle, it works the same as GEN mode. The difference is that the Gen (D) mode will generate the same tone for ferrous and non-ferrous targets at fringe depths but it will discriminate the shallow ferrous targets by emitting a low iron tone.
By Steve Herschbach
I have been laying fairly low with the Nokta Impact so far. Part of that is I have been busy on other things. The main reason however is I quickly zeroed in on how I think the Impact will best serve me as a detectorist.
In general I think I can speak for most people when I say we all like lighter weight detectors. However, one area where lighter is not better is when you use large coils. Balance is every bit as important as weight as it determines the amount of torque applied to your wrist as you swing the detector. A large coil on a very light detector creates a very nose heavy detector, one that will put more strain on you when you detect than a heavier but better balanced detector. It just so happens that the Impact with the rear mounted battery power/speaker module is a good design for a large coil from an ergonomics standpoint. This is especially true when in my experience Nokta has designed large coils that are quite light for their size. I was probably one of the first people that really zeroed in on the new IM40 15" x 14" DD coil when it was proposed for the Impact by Nokta. I got on an early wait list for the coil, and just received mine.
Nokta Impact IM40 15.5" x 13.75" coil with scuff cover
The IM40 DD coil measures 15.5" x 13.75" and comes with a fitted skid plate/scuff cover. The coil weighs 1 lb 13.0 oz or 822 grams as pictured with skid plate and cable and weighed on my postal scales. Yes, I had to say that as some people exclude cable weights from coils! For comparison the stock 11" x 7" IMP29 coil weighs 15.7 oz or 446 grams. I like the flat blunted ends on the IM40, which does help the Impact stay upright as the trailing edge of the coil acts as a flat bearing surface when the detector is at rest on the ground.
I am not usually a fan of larger coils and in fact tend to lean to smaller coils for a lot of my urban metal detecting. Large coils "see" more area which can work against them in highly mineralized ground or in areas with lots of closely spaced trash. However, large coils even if they do not get more depth in highly mineralized ground can cover more area faster, and often ground coverage is every bit as important if not more so than depth. In medium to lower mineral ground a large coil can also offer that magic thing all detectorists crave - more depth!
The Nokta Impact has another trick up its sleeve that favors large coils; the ability to change operating frequency on the fly. High frequencies offer more sensitivity to small items and quicker separation in dense trash as well as extended battery operating time. The main issue with higher frequencies is they also "light up" highly mineralized ground and hot rocks more so than lower frequencies. This can work against machines that are locked into higher frequencies when attempting to employ large coils in highly mineralized ground. Lower frequencies give up some of the high frequency "hots" on small targets but also are less sensitive to ground issues, including salt mineralization. The ability of the Nokta Impact to run at 20 kHz, 14 kHz, or even 5 kHz makes it very well suited for running very large coils. This is accentuated by the plethora of all metal modes available on the Nokta Impact which can deliver extreme performance when coupled with a large coil.
The bottom line is I think the Nokta Impact and IM40 coil may be one of the very best options available for a person wanting to run a large coil on a VLF detector, with depths in all metal modes and milder ground that will challenge many PI detectors.
For a lot of what I personally do, like gold prospecting or beach detecting, I will first attempt high frequency, high gain operation and then back off as ground or EMI conditions require. One thing it is important to know when running the Impact with large coils is how the Gain control works. If the Impact is running at Gain levels that are too high, the OVERLOAD message will appear on the screen. Note: You can increase or decrease the overload volume with the on/off button. When the volume of the device is at maximum, the overload volume will be low. As the volume of the device is lowered, the overload volume will increase. The electronic Gain has at least three distinct levels. There are distinct boosts between settings of 39 and 40 plus again between 69 and 70. Setting over 90 are a sort of hyper-Gain region only obtainable in low mineral/low EMI environments.
Therefore I may attempt to start out in 20 kHz and a very high Gain. If overloading occurs I will lower the Gain for smooth operation, paying particular attention when I get down to 69.
From there on down I need more field time, but at some point it will be better to drop to a lower frequency than to continue to lower the Gain setting. So in theory if at a setting of Gain 39 I still have issues at 20 kHz, it is time to go to 14 khz and run the Gain back up high. If conditions are still not amenable to running at 14 kHz and high Gain settings, I would then drop to 5 kHz and again attempt to run higher Gain levels. Note: people hunting larger, higher conductive items like silver coins and brass relics may very well just start out at 5 kHz. My focus is usually on lower conductive, smaller items i.e. gold.
I so far have only done a small amount of detecting in a local park. I first tried Di3 and while it was working well enough the trash density was high and interpreting signals with a large DD coil can be challenging, especially when the coil generates multiple signals on very shallow items. I finally went to the unique GEN(D) mode and it was night and day. The GEN(D) all metal mode combined with the VCO effect makes sizing targets and identifying shallow targets a breeze, even in a trashy park situation. Shallow ferrous is easily identified also using GEN(D).
There are several all metal modes a person can employ on the Impact as well as the extended range ground balance available in the COG (COnductive Ground). While the Impact performs ground balance in the range of 20-90 automatically in the other discrimination modes, it ground balances in the range of 0-90 in the COG mode. This enables easier ground balancing on conductive grounds where normally ground balance cannot be performed at all or performed with difficulty, such as salt water beaches. Remember that ground balancing to salt conditions always comes at the cost of reduced sensitivity to small gold items.
There is more I could mention about this subject but I really need time to get the hours on the Impact running the large coil to get more into specifics about how to get the best performance out of it. Large coil VLF hunting is not for everyone and is not a magic bullet in any case, but it does offer possibilities for the more adventuresome detectorist. I will close with a picture of my Nokta Impact with new IM40 coil. The detector with this coil is only slightly nose heavy (keep the rod as short as possible) and weighs with batteries 5 lbs 2.0 oz (5.13 lbs) or 2322 grams.