UKD2User

Absolutely. Ohmic losses (simply warming up the coil!) are greater at lower frequencies.

I think it's really important to understand that all D2 search modes, including 'Deus Mono' transmit a set of frequencies into the ground. The transmit waveform in all cases is a pulse-train with square-edged pulses. All such pulses contain a set of frequencies ('harmonics') - most strongly at three times the pulse repetition rate and less strongly at five times the pulse repetition rate (the third and fifth harmonics). I attach a snapshot from page 43 of the manual which shows that the maximum frequency used for detection is declared to be 135.7 kHz - which divided by three is 45.23 kHz - acknowledging that there is (at least) a third harmonic component in the signal transmitted. If you select 45 kHz in Deus Mono mode, you are also transmitting at 135 kHz simultaneously - whatever you do. How the machine chooses to make sense of the return signal is a trade secret - there are some clues in the manual ('subtractive' vs 'additive' algorithms - presumably adding or subtracting results in different frequency bands). I think it's a given that the D2 will analyze the return signal using exactly the same type of (DFT) algorithm as used to produce the spectrogram in the video - to give target/response info across different frequencies. Only XP know how the D2 processes the return signal in 'Deus Mono' mode, but I would guess that it uses a D2 not a D1 algorithm (to give more reliable TID at depth etc that is obtained by examining the response across multiple frequencies). I don't think that underwater you need to worry about EMI, so SMF is the way to go in all cases. I think that the effectiveness of a 'noise cancel' is limited when the EMI is evenly smeared out across the frequency spectrum (broadband noise vs narrowband noise). Modern EMI sources like cellphones tend to generate broader spectrum noise, making them less easy to eliminate. Clever digital signal processing algorithms - making use of correlation between the transmitted and the received signal - can go an amazingly long way to eliminate the effects of even broadband noise. PS the video also shows the 'noise floor' in that indoor environment!

Another excellent video. I believe that the presenter is an XP engineer. It's been available in French for a while, but it's nice to have an English version, just to make sure what's actually being said!! 🤔😁 I see that Gary's videos are sometimes translated into French...

No, it has a larger energy capacity and a different form factor (than the EQX 6/800 battery at least). MC = 25Wh and EQX6/800 = 18.5Wh

While on the subject of Ground Stabilizer, and returning to the topic of 'ground shocks', as the D2 manual describes them, I wonder if people have been hearing physical impacts on the coil by, for example, stubble, because they have Ground Stab set at a value of 1, instead of the more usual 2. Reading the manual, it becomes very clear that when the machine is sailing close to the wind (ground), with GS = 1, the possiblity of noise from coil shocks/impacts is increased.

This mirrors my experience of owning all three coils - the 9" and the 13" are the two I actually use, with the 11" as a backup/spare.

It's very good to see some objectivity supporting what I already intuitively 'know' - or perhaps you could just call it 'confirmation bias' (😁!). I installed V2.0 as soon as it was available and would not go back to any other version. I seem to remember reading Tom Dankowski, on his forum, suggesting - in a completely different context - that a certain amount of 'bump sensitivity' is a good thing. I guess because it shows that the machine is working to the best of its capability.

Truffles ??!! 😁👍

New features added, I seem to remember - also the WS6 was given almost all the features of the remote, except XY screen and multi-program saving. V2 also fixed some of the 'fixes' in the earlier V1.XX !!

That is the middle section I used (I actually bought it from Detect-Ed at the same time). I didn't drill holes in the top end, I simply used a dab of polyeurethane gorilla glue to hold a replacement XP clip in the top end of the tube. I kept the Nokta camlock at the bottom end - it is a little larger than the XP equivalent (and a teensy bit heavier!) - mainly because I'm not sure if the XP camlock requires the same cutout in the tube (I couldn't be bothered to check!) - it works just fine. I actually use this rig with the Lite stem - overall it's a couple of pounds lighter than the Manticore (both with an 11").

It's not just the lightness of carbon which is so good but also the, erm, stiffness...... 🤐😀

I got two Detect-Ed stems for my 13" and my 11" and I relegated the XP 'CF' stem that came with the 13" to the 9" coil. I love the Detect-Ed stems, but didn't feel I could justify the extra cost of a third! I also replaced the upper section of the stem with the carbon fibre/er stem from Nokta, designed for the Legend/Simplex - it fits perfectly.

https://www.bbc.co.uk/news/science-environment-56337876 😀👍

A trick that was popularised by Gary B, and is used by at least one YT D2/MI user, is to glue a small disc magnet with epoxy or similar onto the end cap - a good way to discriminate/eliminate stray iron in the hole. My D2 continues to surprise me by the way I often find several nails etc in the hole with a nice non-ferrous item.

And magnitude of course (it's a vector, not scalar, quantity).

The truth is, nobody (outside those who need to know) knows - because the code is proprietary, and is protected by encryption. There is clearly processing which creates a sound-based representation of a target, and separate (but obviously closely related) processing to generate as reliable a visual TID as possible. These processes may well go on in parallel, although the visual TID seems to be time-averaged, and therefore, later than the audible representation. Notching and disc are both, on the face of it, processes which require a TID, of some kind - probably not the same as the one displayed visually - to have been calculated first - but I'm sure it's more complicated than that!

The number 25 is just a number. It represents a factor by which target signals will be 'corrected' to take account of the fact that the ground has some magnetic/conductive properties due to mineralization. Loren Lemke gives a really good explanation of this from around the 20th minute of his YT video:

There is an externally identifiable difference - the transmit waveform is different - it's stepped and looks like a very crude triangle wave (which will have different harmonics). There are almost certainly differences in the way the return signal is analyzed but these will most likely remain trade secrets (unless the encryption can be broken). Most other modes use a transmitted signal which is essentially a repeating square wave with two alternating duty cycles. The HC transmitted waveform requires more battery power (because it has more low frequency energy and the coil suffers greater resistive losses) - the Manticore does something similar, and this is the origin of their 'more power into the ground' marketing guff.

I'd be fascinated to know how you know this, given the level of encryption protecting most embedded code in modern detectors - have you seen the source code or reverse-engineered one/several? Yes, I'm sure that target responses at multiple frequencies are compared/correlated in various ways, but 'accumulation' (if it means anything very much) suggests simple addition. We know that the D2 , for example, uses more than one kind of addition and/or subtraction in processing the return signal - there are almost certainly other transformations going on. The great beauty of processing signals digitally is that you can do all sorts of things with them - in the time domain and/or the frequency domain.

I don't think it's possible to say that most of the EMI mimics the "signature" of a good target - a little will, most won't, I'd argue. By its nature EMI is unpredictable. The response signal from a target is very strongly correlated with the (precisely known) transmitted signal - but (almost by definition) uncorrelated with extraneous EMI. 👍

I think it's more subtle than that - analysing the return signal over a range of frequencies (what we know as SMF) ought (other things being equal) to give an opportunity to reduce the overall effect of noise (EMI and/or mineralization) through clever signal processing e.g. some kind of (auto-) correlation process, on the basis that interference will not affect all frequencies equally at any given time. Of course, a lot depends on the nature of the noise - its 'spectral power density'.

How do you know this? My impression is that the Manticore just lets you cycle through the available wavebands continuously over a longer period (and combines the results in some way that they do not give detail on). My impression is that the D2 and the Equinoxes (and probably others like the Legend) are not random, but only sample each possible waveband once during a given 'noise cancel' session.

I have found that a good way to reduce the audible effect of EMI is to reduce Audio Response, followed by reducing Sensitivity (or Salt Sens first if using Beach modes)

I have had no problems with updating from 0.6 to 0.71 thence to 1.01 and to 2.0 I know that the WSA's need to be updated to the same SW version as the puck/RC or pairing will not happen - did you remember to upgrade the WSA software version too?

Same here! 👍