machine to find a void /tunnel

i am trying to find this drain and need some tips on what machine or proggy to use .any ideas ?
tried the deus but no joy yet

Whites 808

Some of the Whites 808 dont have the Cave mode. Try the Whites 800 or Discovery 900....These two are the same machine with Cave mode.....Discovery made the 800 for Whites.

Nokta Invenio Smart Detector -

[www.earthscan.co.nz]

"Your best probability is to use a detector that has a Threshold feature and an ALL METAL mode - doesn't have to be a true all metal mode but either should work?

Don't 'crank up' the Sensitivity just yet. Set it in All Metal and begin to scan the suspected area.
Walk forward with a Loud Threshold and adjust the Sensitivity as you go and this could be dependant on spurious signals you are hearing, shallow / deep trash / items of no interest?
The detector 'should react' to ground changes and differences in moisture and can result in 'phantom signals' that to the experienced detectorist can sound just like a hot rock behaves!
That is, when a signal is heard you can't 'pin point' it, and it seems to be signalling [ AFTER ] you sweep - so the SIGNALS ' should be' on the LEFT and RIGHT of the suspected area at the end of sweeps!


Several years ago this worked for me as I was asked to search a military area for ordinance that might have been present and then removed and thus leaving behind a 'void'

The 'X-Terra 705 w/10.5" DD coil' was what worked for me"



Edited 1 time(s). Last edit at 07/11/2018 03:44PM by Des D.

One thing I would add to what Des has said and that would be to use a machine that allows you to lock the Tracking/Ground balance because when you have the Coil over the Void the detector will no longer be ground balanced and will become noisy alerting you to the fact. Which is why the Whites TM 808 no longer has the Cave/Void setting because it is just not needed when you use the GB to alert you about the ground conditions.

hope that helps,

Don't know the size of your drain.
Deus, use gold field program, reduce reactivty down and IAR setting.
Run GB at actual ground setting.

For more information on the proper use of Cave mode (TR Void), which is a diffrent mode than all metal GB, you can go to the Whites Electronics (metal detector) website and download the owners manual of the TM-800 for free. This can be done by clicking on the Tech Support tab at the top of the page....then click on Manuals. Type "800" in the search box titled.... Search Manuals. Hit Enter and it will take you directly to the list....English/Spanish versions. I have used both the 800/900 in Cave mode, it will detect any disturbed ground or void. You could compare TR and GB modes....not so, on the stripped down 808. The Lost Treasure magazine website also has a Field Test review of the the Discovery 900, which may help with the basics. Thanks....... also if you find an 808 double check the features, some very early versions had the Cave mode...hard to find tho.



Edited 1 time(s). Last edit at 07/12/2018 12:23AM by Arkansas.

tnsharpshooter Wrote:
-------------------------------------------------------
> Don't know the size of your drain.
> Deus, use gold field program, reduce reactivty dow
> n and IAR setting.
> Run GB at actual ground setting.

what frequency is advised? and what tones will i get when over the void ?and will it be consistant ?

Did you consider employing 'a human diviner?'