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TDI as a Beach Machine
Posted by: cjc
Date: August 10, 2017 09:43PM
On a freshwater black sand beach, there's no way you could run say, a GQA2 at its fastest delay--down near 10 uSc. I'm learning that the TDI is no different and although this is its deepest setting the tradeoff is instability and reduced depth. When you bring it up to about 14 or 15 uSc (10:00 o'clock) the warble settles down a lot. This lets you use more gain. I realized that the in air performance was just that--at high Gain or 10 uSc. With the GQ this is more obvious--sounds like hell. With the TDI though it doesn't sound that bad with slightly lowered Gain, but the "one-way" responses are an indicator that the signal is not penetrating--there's a lag--almost like when you run a PI with mismatched phones. I'm not even using the GB--still a lot to learn.

Re: TDI as a Beach Machine
Posted by: Old California
Date: August 19, 2017 09:54PM
I think if you go with a smaller coil with the TDI you should be ok in black sand, I'm using a MinerJohn 10" x 6" folded mono coil at 10uS no GB with the TDI in fresh water black sand here in California. Using high Gain as well, It's extremely smooth.

With the GoldQuest, Try increasing SAT this may help it operate with smooth stability at or near 10uS. Plus, From my experience the Gold Quest actually is closer to 10uS the TDI to me appears to be somewhere between 12 and 13uS?

Appears we have the same equipment, try those settings with the GQ. And go with a smaller coil on the TDI, hope this helps.


AKA..Paul (Ca)

Whites GoldMaster BFO
Compass Klodike BFO
Bountyhunter BFO
FisherScope TR
Metrotech TR
Detectron TR
Rayscope TR
Mity Mite TR
Garrett BFO
Goldak TR
Relco BFO
Jecto BFO
Roach TR

Edited 1 time(s). Last edit at 08/19/2017 09:56PM by Old California.

Re: TDI as a Beach Machine
Posted by: Mega
Date: August 20, 2017 05:54AM
I dont own a Gold Quest but i do own a TDI Pro using a similar setup as Paul does,currently use mine with the Jimmy 9x5 folded mono coil as a everyday use coil,running mine at about 15us and also in low conductivity,gain about 12.00 and it runs as smooth as anything,hits on the small targets but rejects almost all iron that i have on my sites.As most of my desired targets are hammered silver coins or roman coinage then low conductivity is the best position for these types of finds.

Was on a roman trading villa site a few weeks back and its a tremendous way from the coast maybe 70-80 miles away,but this site is basically like black sand and possibly the most difficult inland site that most folks would encounter but the best tool for the job was the TDI Pro and the 9x5 folded mono,Still blown away how this machine being a Pulse rejects most iron targets but lets through my desired one.Loving this machine more and more,but i will admit it has taken some time too master it,but well worth it.

Deus and Nexus MP main everyday detectors

Displays on a Detector are really the equivalent of relying on sub-titles,give me a Analogue machine anyday.

Just some of my site specific use machines.
TDI Pro 20'' Mono
Nexus SE dual 9'' coil
Nexus MP 14x13
Fisher TW-5 twin box
Crossbow PI 14x9 Mono
Mirage PI 5'' Mono
DFX 18'' Detech
T2 SEF15x12
IDX Pro 15'' Concentric
B1 and B3
Trident11 Extreme NEL Snake

Mainly hunt deep ploughed and pasture sites,trashy roman/saxon and celtic permissions.

Re: TDI as a Beach Machine
Posted by: cjc
Date: August 21, 2017 10:12AM
Thanks for your feedback, Mega. I really appreciate hearing from some experienced users of this machine. There's a lot to learn but the potential is certainly there. Kind of unusual--the key is learning to turn it down!

Re: TDI as a Beach Machine
Posted by: cjc
Date: August 21, 2017 10:20AM
Thanks for the suggestions, Paul. Good plan to lose the stock coil for something smaller. That's the Cuda's strength--the coil size. The GQA2 is an awesome detector too-Mr. Bill originally suggested I run 10 / 10 which has worked well but it will do some interesting things down at 10 uSc. Up at full SAT its great in the interference zones --hills mixed ground--gets stuff the Excal crowd cant touch. Also have a CS6Pi with dual range SAT --the "sisters"...
regards, clive

Re: TDI as a Beach Machine
Posted by: stephenscool
Date: August 22, 2017 10:02PM
I run the sl version. Delay around 13. Gain 80%. It still picks up every little tid bit in range but a good target is easy to distinguish from a crappy 1. Even beaver tails give a sharper metallic sound. Bottle caps and clad coins drag out for a fraction of a second longer. The discrimination I get using this setup is in par with an excal. I still dig it all but have never found gold when I was expecting a crappy target.

Edited 1 time(s). Last edit at 08/22/2017 10:08PM by stephenscool.

Re: TDI as a Beach Machine
Posted by: cjc
Date: August 23, 2017 10:12AM
Thanks for your reply, Stephen. This is the kind of thing Im trying to learn. Big difference when you go up above 10 uSc. Smoother, pins easier to hear, not much of a loss on gold either.

Re: TDI as a Beach Machine
Posted by: stephenscool
Date: August 23, 2017 12:48PM
10usc it's hard to tell the difference between metals and sometimes size. Last night hit an 18.8g gold link bracelet. The entire target was a smooth signal. No elongation or extra chatter. I wasn't expecting gold, but at the same time it was a dig signal. On occasion I hit silver bangles larger than the inner coil on the stock coil (stretched open). Can't remember how the sound on the stock but on the 8x14 it's 1 smooth signal. If I'm unsure about a signal I will go over it a few times with different speeds...if something isn't right it will reveal itself.

Re: TDI as a Beach Machine
Posted by: cjc
Date: August 23, 2017 08:41PM
Ya, big difference in response characteristics when you go up above 10 uSc, One trick that's helped me is to wiggle the cond. switch when you have something pin sized--often it will reveal the double tone. I need this machine to go deeper than a Dual--which is pretty deep. Seems to do just that but at 10 uSc there's no consistent deep responses to be heard--at least not in black fresh water sand. 13 or 14 uSc seems to be the way to go. Didn't you post about the Fq control somewhere?
Great info thanx.cjc

Re: TDI as a Beach Machine
Posted by: stephenscool
Date: August 24, 2017 01:52PM
Another trick I use is the threshold and volume control. I turn up the headphones and turn the threshold just audible and only dig whispers. The shallow targets will blow your ears out and give you a headache after a few hours if there are too many.
This is the sl version with the smooth threshold. Don't know how it would work on a Pro

Re: TDI as a Beach Machine
Posted by: cjc
Date: August 25, 2017 06:32PM
I also find that backing the Vol off a bit takes the annoying highs out of the warble.

Re: TDI as a Beach Machine
Posted by: stephenscool
Date: August 26, 2017 04:50AM
Sl there is no warble. That's why the volume trick will work. The df or pro it would likely be a problem

Re: TDI as a Beach Machine
Posted by: stephenscool
Date: August 27, 2017 12:07AM
The sl might not be as deep as let's say the pro or an atx. But the threshold is always smooth and any target within range will give a signal. Digging or not is up to the user.
I used to hunt a bay beach with the df. Black muddy place, little movement. Hit it daily for 2 months. Bought am sl and the 1st hunt pulled 150g of silver. None of it terribly deep. The sl will hit necklaces at depth that the atx just skips over.
I'm willing to give up that inch or 2 for the smooth threshold

Re: TDI as a Beach Machine
Posted by: cjc
Date: September 08, 2017 07:35AM
Ya, I ran my Pro in salt for the first time--really tough to tune finally needed to be up at 17.5 Gain maybe 1:00 o'clock. Hardly deeper than a DF like that.
Im going to ask around about how a SAT circuit would work--probably a dumb question.

Re: TDI as a Beach Machine
Posted by: stephenscool
Date: September 10, 2017 09:55PM
I don't have the time or resources to tinkle inside the box. Many of these tips almost sound like quotes from 1 of your books. Strangely enough I could only really skill develop with a smooth threshold. I did ok with a df.. but it was more of a beep and dig. The tdi sl allows skill devolpment with the right coil and techniques.

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