karelian

White's evolution vs revolution. Given the reality of the fires that  impacted Miner John it is clear White's has been forced to make other arrangements, taking the opportunity to repackage the Tdi SL. Same machine with just a new coil? 'New Patent' could mean it is not a folded mono or duel field coil but something new. Something to get excited about? Need user input and better photographs of the new coil.. White's needs to step up and communicate with customers.  Karelian

Before you know it, more shelf space is required.. just a glimpse not including research materials etc..  you have been warned!

All the best, Karelian.

PhaseTech is a dealer in Australia and has tried the Evo coil on a customer Tdi, seemed to run well. He mentioned it earlier in this thread. He had a good reputation for calling it the way it is, so I'd say it's probably more than just OK. Sadie has well established reputation on Tdi machines, Evo coils also on GPX whilst new to TDI series.. takes us back to PhaseTech who could provide more relevant info. Karelian

Still plenty for sale in Australia, new and second hand. Evo could be the future, I'll get around to trying one after I've completed my coil cull.. Karelian

The Detech works well with both Tdi Pro and Tdi SL just don't advertise it I guess.  I had the opportunity to try and then buy. . If your coil is stable and performs quietly etc in your soils then performance improvements will be marginal or insignificant. If the duel field is noisy and unstable in your ground then a mono will see improvements across all fronts. Again Jim In Idaho made a video doing a direct comparison, could answer some of your questions. 

The duel field coils do well in low to moderate mineralization, but when the soil is hot in Australia they transmit more ground noise and are more difficult to ground balance than mono coils;  in my experience. This is particularly true for the larger coils and less so for the small ones. I only have experience with the White's 12" duel field and the Jimmy duel field coils. Most of the mono coils beat the duel field Jimmy  in Australian soils. The Sadie was the best of the small coils and the Detech equals it. Slight advantage to the Sadie on small gold and slight advantage to the Detech on larger deeper targets. 

If the Jimmy coil is equal to the  7.5" White's duel field then I can say the Detech 8"  which is near identical to the Sadie mono, will have a clear advantage in hot ground encountered in Australia. This would be  reflected in the coil chart results between the Jimmy and Sadie.  Hard won life lessons, plus an army drill instructor have pointed out that behind every stuff up there is an assumption. The above opinion is based on at least one assumption... since I've never seen or used the White's 7.5" duel field coil, only the Jimmy. Also White's didn't promote the duel field coils in Australia, instead providing the mono versions on local machines. Jim In Idaho has posted a video comparing the White's 7.5" duel field and Sadie in the USA, probably more useful than my Australian experiences. Seems that in the US soils,  the performance is very close.. Type of ground and levels of mineralization seem to be the determining factor in Australia and probably also in hot US ground.  Hope this is not a confusing or contradictory answer and is useful to some degree. 

All the best, Karelian

Darn it, my MXT with 6x4DD and 5.3 Eclipse is going back into the boot. Too easy to forget that VLF machines, although  somewhat difficult to manage in hot ground; have some interesting capabilities.. karelian

First day out into the Golden Triangle, last day with decent internet for a while.. Always present my new machines to the mother of all nuggets memorial.  'Christened' at the golden alter so to speak... an old habit, just hoping the luck will rub off I guess.. The 'Welcome Stranger' was found at a depth of an inch according to Memoir 12, which is the list of nuggets found in Victoria.  

The 16v pack is working well, no issues with heat or reliability. The  TDI SL LE is super light and well balanced, very easy to swing for hours so I'm enjoying it. Great weather, the flies and ants are not an issue so far. Best time of year to get out into the goldfields and swing your thing..  all the best.

Karelian.

When I first got a Tdi it was a SL bought over to Australia from the USA by my brother. It came with the  Duel Field 12' coil, a Jimmy Tdi Dual Field mono and the mini Jimmy mono 6 x 4. The mini never saw any use, just too small and the big 12' was my beach coil for a long time. Everything else fell to the  10 x 6 Jimmy and it was my first choice on the goldfields until the Sadie came along. Never could work out how to employ the mini Jimmy, should I consider it as a probe to poke into a crevice? When there is so much ground that 6 x 4 mono looks so small and on a PI it didn't make sense to me at the time.   I think these coils were made for Jimmy by Whites?  Certainly rare beasts in Australia. Karelian

The Tdi Pro is in my humble opinion a very stylish and functional design, as is the Tdi SL. In a sense they are brothers so your confusion Jim in Idaho is understandable. Karelian

Jim in Idaho those lithium cells are 1.8 volts + when fresh. I started with name brand disposable lithium cells for emergency use, always keeping a few packets handy. After a while I used them in radios and torches and finally the Tdi SL. Found a cheaper 'Wallaby' brand available from a local seller in Melbourne. A bit hotter to start with than the big brands. Too expensive to use on a regular basis but when a new machine arrives in the mail..... why not? Special occasions and for emergencies only because of cost. The new battery pack will save me a few dollars in the long run since I have lots of 18650 cells. That 12 x 8 MJ did well, should improve with the more powerful 16v pack on the SL and I have not jet mounted it on the PRO. Best time of year for Victorian goldfields, the flies have not hit peak numbers, the ants and snakes are still a bit slow from the cold. Looking forward to it.

Karelian

The White's Super Pulse 220 coil was intended by me for beach use only.  I was surprised that it performed  so well on the goldfields. Quiet and stable with good performance in hot ground. If you can get one it may be an excellent alternative to the 12 OZ mono.  Good size and not bad on smaller targets. No bump sensitivity or issues at all, very good all rounder. I remember White's sold these off at bargain prices in a sale, so there are some very lucky individuals out there who scored a bargain. I like it.  Karelian

Jim in Idaho, very soon I've got a week long trip into the Golden Triangle here in Victoria. Both the Tdi Pro and SL have space in the boot. For the first time the MXT is staying home.  There is a reason White's chose the 8 x 12MJ coil for the Limited Edition and I look forward to trying it in the goldfields. The new battery pack and a good supply of batteries will allow me to give the SL a good run. Generally the Tdi SL is my loaner machine and 'urban PI' (Who coined that phrase?). I suspect the Pro will see the most use but curiosity demands the new SL gets a workout. 

Jim in Idaho I did a quick air test on the Limited Edition when it first arrived in the mail. Used the standard battery pack loaded with cheap disposable Lithium batteries for a total of 14.7 volts. I did record the results, as always.. Karelian

1 grain ingot                8cm

0.5 gram gold coin   25cm

1/2 Sov.                     34cm

US 1/4                       30cm

AllenJ, the air test was conducted with the White's Super Pulse 220 coil. The coil that came with the Tdi SL Special Edition has so far not seen much use. I also used an external speaker, Nokia MD-11 which works almost as well as good headphones. I like the Miner John coils for their weight and  performance, but I'm spoiled for choice. Because the Tdi SL has seen mostly beach use I have used the Super Pulse 220 and the Jimmy Sierra 14 x 8 mono that was made for him by Miner John. I don't use the folded mono coils on the beach. Because of the Coiltek Tdi 6' mono and Sadie I rarely use the smaller Miner John folded mono coils. I do like some of his larger coils for their blend of performance and super light weight. That 14 x 8 is good on all sized targets encountered on the beach and is as close to a 'bigfoot' coil I can get. It covers a lot of ground quickly.  Karelian

I haven't tried any of the flat wound Evo coils,  nor the Detech 11' Ultra. Last coil I ended up buying was the Detech 8 mono which impressed me a lot. Probably nearly as good or equals the Sadie on the small targets and has a small advantage on larger deeper targets. I suspect the round coil shape has a lot to do with that. I use it on the beach and in wet/muddy areas because that Detech is a solid little thing and waterproof, it gets all the dirty jobs. The Sadie doesn't see mud or water.   I'm in the process of culling coils at the moment and that will finance new technology. The mono 8' and Sadie are both keepers. Ground coverage and small gold sensitivity are a winning combination so I can see how the flat wound coils appeal. Karelian

PhaseTech, I didn't use any PVC pipe, what I did was use a short star picket combined with a hammer. I'd hammer the picket into the side of the hole, making sure to make a decent cavity at least 40cm deep into the side of the miners hole. This was followed by  wedging a pieces of sharpened flat wood with the targets firmly taped on. Maybe not burial in the traditional sense but it worked. Yes I did have to lift the coil up off the ground to get fine tuned depth measurements, but never more that 5cm,  anything higher and we'd just whack in another hole.

I had a flat enough surface or level ground and just had to even the side of the hole for accurate measurements. Only problem I had was targets near the surface, as the picket was a bit brutal and the ground would crumble.

Ended up having to bury the 1 grain ingot from the surface and one of the 0.5 gram coins. I'd swing the detector and my trusty assistant would do the measuring. Had to abandon the star picket and use my beloved soil knife for the other close to surface targets. What I remember most is that the process was slow and the flies were determined to drive us nuts. Not keen to repeat the process. There is something to be said for test sites and PVC pipe.

Karelian

Completed product, the carbon fibre arrived so some cosmetic changes only. No danger of using this by accident in my MXT or XL Pro.

A nice project and I am satisfied with the outcome. Karelian

GB-Amateur, better display of results than I could ever manage, can't MS Excel to save my life. Must confess I obtained my Sadie second hand, just love good finds be they in the ground or in the classifieds. When I go into unfamiliar areas I always swing the Tdi Pro with the Sadie coil, it will let me know what is on offer and I have confidence in it's ability to pick up the small stuff and still punch deep.

Hopefully I can make both interesting and meaningful contributions going into the future, all the best GB-Amateur.

Karelian

Just a few images to better show what is meant by mineralized ground. Run a magnet through this ground and it will be covered instantly. When I say nuggets found in this area, depth ranged from 4 inches to three feet and weights in the hundreds of oz. Diggers focused on the areas surrounding the 'monster nuggets' and turned their noses up at smaller gold in a nearby gully.  The area was rushed twice and has seen lots of attention from modern electronic prospectors. Nearby gullies still deliver little teasers whilst still hoping to find my own 'monster nugget'.

All coils ground balanced well on the test site, the only coil that was a bit difficult was the Whites 12' Duelfield, it balanced ok but ground noise was constant, useable but it wouldn't quiet down for long. The other duelfield coil was the Jimmy 10 x 6 as it was OK and better than Ok in milder soil. The Sadie was a stand out and both the Pro and SL love it.

I did a coil test some time ago using a Tdi Pro OZ, quite a variety of coils involved. Just a bit of information not wanting it to go to waste.

The test area was located in the middle of the Golden Triangle in Victoria, Australia. Looking at the images the test site is located on a area that produced large nuggets. Heavily mineralized to give the depth tests some authenticity. Targets were varied as were the coils tested. The Tdi Pro was ground balanced, gain was at 5, conductivity was in ALL, pulse delay was 10. Frequency was set in the middle and the audio was boosted by a Nokia MD-11 external speaker. Only clear repeatable signals were recorded.

All targets were buried in the ground sideway from a miners hole, so as not disturb the soil on the surface or above the target. Only the 1 grain ingot and one 0.5 gram gold coin were buried from the surface disturbing the ground.

Not sure how useful this is for Tdi SL users, deduct 10% maybe.. Just gives a sense of what is realistic is this one location at that one time with the Pro with the variety of coils available back then.

All the best, Karelian

I ran the pack for 4 hours to check the drain in voltage over that time. Personal habits mean I'll rarely go over 4 hours without a break so that is my personal time limit. I was using 4 x 18650 3400 mah Panasonic NCR18650B cells. The Tdi SL had an threshold hum using the speaker, to maximise power use and the coil was a 10 x 6 mono by Miner John. A cool day, fresh and pleasant. The pack was warm but not hot during testing.

9.00    am start. 16.4 volts.

10.00 am            15.5 volts.

11.00 am            14.9 volts.

11.30 am            14.6 volts.

Noon                   14.4 volts.

12.30pm            14.15 volts.

1.00 pm             13.9 volts.

Faster drop in the beginning and slowing down as the cells discharge further..  I'll swap out for fresh cells after three hours to maximise depth. The design allows for it and I have spare cells so three hours will be my limit. Still way above the starting voltage for the three cell battery tray and other options.. 

All the best, Karelian

Just having completed the project, I decided to do a quick check to see if the increase in voltage is worth out time, simple air test would lean towards a yes vote. Should mention that this design requires the use of the flat Panasonic cells without any protection circuit. So I use a smart charger that will not over charge cells and I'll check to see how long the 4 x 18650 pack lasts before it requires fresh cells. Yes this design allows me to carry fresh cells and swap out when required in the field.  I managed to retain the original White's battery holder cover. No smoke or issues were present when using the 4 cell pack, seems to handle the extra voltage without issue.

I did a quick air test comparing the Orange 3 x 18650 pack with the modified 4 x 18650 pack. Finally compared the results with a Tdi Pro using the same coil.

Tdi SL with gain a max, conductivity in all, pulse delay at 10, frequency in the middle. Using Super Pulse 220 coil.

12.38 volt gave 6cm on 1 grain ingot, 24cm on 0.5 gram gold coin, 32cm on gold Half Sovereign, 27 cm on US Quarter.

16.48 volt gave 8cm on 1 grain ingot, 26cm on 0.5 gram gold coin, 35 cm on gold Half Sovereign, 30 cm on US Quarter.

Tdi Pro     gave 8cm on 1 grain ingot, 27cm on 0.5 gram gold coin, 36 cm on gold Half Sovereign, 33 cm on Us Quarter.

Must mention Tdi Pro had gain set a 5 whilst the SL was on MAX...

All the best, Karelian

I was looking for battery tray design for my Tdi SL which would allow 4 x 18650 batteries. As luck would have it on the local Prospecting Australia website  XLOOX posted a simple mod for a Whites factory battery tray. I don't know how to post links so the full description is to be found in the Prospecting Australia site. Simple cut out the guts of the tray, leaving the original battery connectors with mods on one end and a copper connector on the other.  I can fit Panasonic NCR18650B cells, without nipples but with protection. They just fit snuggly. The only issue is closing the lid, you need to cut a channel under the batteries into the base of the tray to allow for this. I'll cover this with a thin carbon fibre sheet and look at using a thinner sheet for the cover also. I will also add something to secure the batteries in position. Just waiting for the postman to deliver my carbon fibre sheet before finishing my own version of XLOOX's design. What I like most is that this is simple and cheap. Must confess I am aware of many different designs, since there have been no reports of smoking Tdi Sl machines I have finally decided to give it a go.

All the best, Karelian