Question on the White's TM 800

[keith777]

Hi guys

the chart bellow tells you at what depths the machine will pick up what size objects at. is that from the coil whilst standing up straight to the object in the ground. or from ground level whilst standing up straight to the object in the ground.?

if it is from the coil whilst standing up straight to the object in the ground. by the time you take away the 18" between the coil and the ground whilst you are standing up with the machine in your hand. you are only getting 23" down to the 3"sq object. the xp Deus that i normaly use to detect with can find a target that size and at a better depth as well?

[Funfinder]

These are in air tests under best possible conditions.

If you walk with this 2box detector holding the coil 40cm over the ground the results for
buried stuff will be alot different.

The XP-Deus uses a much smaller coil which can not detect as deep as a very large coil.

The 800 is for walking around and finding stuff that is 10cm or larger.
For smaller stuff you can forget it.

[Skippy]

Basically : Big coils find big objects best, small coils find small objects best. It's a linear scaling thing. Hence a dirty great 18 inch search-coil isn't best suited to find a 0.22 airgun pellet - a 7 inch one would probably be better.
Two-box units behave like very large coils, I'm not sure how large, 30+" ? So they aren't the best on targets a couple of inches across, but start to come into their element when targets get 6"+ in size.

[keith777]

These are in air tests under best possible conditions.

If you walk with this 2box detector holding the coil 40cm over the ground the results for
buried stuff will be alot different.

The XP-Deus uses a much smaller coil which can not detect as deep as a very large coil.

The 800 is for walking around and finding stuff that is 10cm or larger.
For smaller stuff you can forget it.

thanks for the info guys.....

another Question.
would the machine not detect deeper on the minimun size objects if the coils were closer to the ground like a single coil detector does. or has whites done there home work on this machine and that is the way it has to operate.
one thing that i have noticed with the machine is that in the S.A.T motion modes you have to walk as solid as a rock, as the slitest movement up or down when walking will give off a falsing tone. plus if the coil is tipped forwards or backwards a couple of inches or so. but in the NoN Motion mode it will only give off a falsing tone if tipped forwards or backwards. is this normal for this machine?

[Skippy]

That is the way it has to operate. It would pick up too much ground signal if you held it close. You should be able to roughly recreate this kind of searching with your Deus, though a large coil would be best.

[Funfinder]

Absolutly right, I would use the TM800 for stuff that has 8cm (3'') at least while walking around
over bushland or regions with larger boulders, holding the coil 20cm above the ground and in all-metal-mode.

Of course no shovel in the other hand, no backpack with metal-finds on the shoulder, no pinpointer nearby.

I even would hold that coil with left-right direction in front of me so I know exactly whats directly below.


However - the so far best compromise for small but also very large deep stuff at the same time is some
40-45cm coil swept 3-5cm over the ground. Non-motion circuits and no disc. because its more sensitive.

For the real deep stuff even some 50cm is too small - a 70cm x 50cm DD is the minimum !!!
And even such one should be moved not more than 10cm over the soil.



What we really need is a special mixed-mode coil that detects the super smallest and the most
deepest targets alltogether! My idea is using high stable and sensitve small coils but which are at least
60cm away from each other. Together with a very special 2in1 circuit which computes the signal
within the small coils on the one hand on an extra basis but also uses each of those 2 or more small
coils and compares the output of them with the distant other small coils for reaching also the ultra-deep
targets! Of course that small coils need to have to create a tough EM-field which is able to penetrates
even high mineralized soil down to 5 meters!

It's not very complicated to built and the usages weight also is pretty ok.

The question is who starts first with this project an earns the big money !!!

[keith777]

now you are talking Double Dutch to me

[Funfinder]

thanks for the info guys.....

another Question.
would the machine not detect deeper on the minimun size objects if the coils were closer to the ground like a single coil detector does. or has whites done there home work on this machine and that is the way it has to operate.
one thing that i have noticed with the machine is that in the S.A.T motion modes you have to walk as solid as a rock, as the slitest movement up or down when walking will give off a falsing tone. plus if the coil is tipped forwards or backwards a couple of inches or so. but in the NoN Motion mode it will only give off a falsing tone if tipped forwards or backwards. is this normal for this machine?

> now you are talking Double Dutch to me

What topic and person?


Those failure-signals are a results of some factors which can add up:
high or fast changing mineralization, metal on or near the body, too high sensitivity, wrong ground balance or a region full of metal junk everywhere.

Press the reset-button if this MD has any, walk around with no metal at all close to the detector or lower the sensitivity.

And of course the deeper the closer the coil to the ground but this detector is not built to find small coins.

[keith777]

Hi funfinder
sorry about that.
i meant your last post were you talked about a (special mixed-mode coil) i no nothing about electronics etc. i with i did though.

i would love to see a video of the TM800 in use. i have searched the net but i can only find some on the TM808

[Funfinder]

OK, everything clear.

You might mail Whites directly and ask them if they have some TM 800 clips
or about the main differences which are relevant for you.
Garrett also offers some 2box coils for some of their detectors so you can
use them similar as the 800 or 808.

You might find clips on youtube about these or at their homepage.