AlgoForce E1500 And DD Coils

[Steve Herschbach]

I sent Alex some general questions about coils and connections. First, while damage is unlikely, the detector should not be powered on without a coil attached. Also, coils should not be connected or disconnected while the detector is powered up.

The E1500 is designed specifically for the use of mono coils and is wired to run one winding as both transmit and receive coil - the definition of a mono coil. A DD coil may be attached to the E1500 and it will normally operate but with only one half the coil active. One half of the DD coil will act as a mono coil, and the other half will simply remain an open circuit. The is identical to what happens with Minelab GP and GPX models when you run a DD coil in mono mode. From the GPX 5000 manual:

"Using a Double D coil, running in Mono will often increase the sensitivity of the detector but may also be a little more unstable in heavily mineralised ground. Pinpointing is not centred in the middle of the coil, but to the left side, and may give a complex signal when the target is very close to the coil. It is recommended you use the left edge of the coil to pinpoint shallow targets."

To clarify, when they say that the detector may be more unstable in heavily mineralized ground, they mean compered to the DD coil being run in DD mode. Running it in mono mode turns the coil into a smaller, hotter mono coil, which not only increases it's sensitivity to small gold but also ground and hot rock effects.

Alex emphasized that they did no testing with DD coils but that there is no problem giving them a try. This raises interesting possibilities for people who own a DD coil and want to try it. For instance, a Minelab Commander 10" x 5" DD coil would be transformed into a roughly 10" x 3" mono coil if attached to the E1500. It would obviously still be the same physical size and weight, but also might be a very sharp small gold coil that would cover a decent swath of ground. As the DD coils get larger you would be paying a significant size and weight penalty, but on 11" and smaller coils they are light enough already it should not pose an issue. And mind you, I am not recommending people run out and get DD coils to do this. It is just that there are a lot of these coils out there sitting unused and perhaps a E1500 user will already have one, or get one dirt cheap to play with.

Good article here by forum member Nenad (phasetech) on mono and DD coil differences.

Algoforce E1500 Specifications & Manuals

Double D (DD) coil in both DD mode and Mono mode

[JCR]

A mini PI Bigfoot. Interesting.

[Steve Herschbach]

Another tidbit on coils. Minelab coils are generally compatible with the White's TDI and the reverse is also true. This means that most TDI coils will likely work on the E1500 though there is no guarantee of this. My sense is that the TDI was very forgiving on coils and so could use Minelab coils, but that there is an actual difference. Luckily the E1500 can adjust for quite a bit of range between coils. Just like not getting a DD coil just to try I'm not sure I'd get a TDI coil specifically for the E1500, but there were some very different coils made for the TDI that I would like to try myself. Specifically a little 4x6 mono, the smallest mono I have ever heard of that is not a pinpointer.

The TDI dual fields are a type of mono coil with an inner and outer coil running at the same time and should function properly with the E1500. The inner coil design was specifically intended to boost the inner small gold sensitivity on larger mono coils, which are typically edge sensitive and weaker in the middle on the tiny bits.

The old Coiltek PI pinpointers for the Minelabs should also work on the E1500.

Various Jimmy Sierra coils for the White's TDI

 

[phrunt]

I've been wanting to buy a 10x5" Commander DD since I discovered this, there was a guy selling a second hand one forever on our local auction site, I mean for years it kept appearing on and off and now when I want it, it's gone!   a 10x3" I think on this detector would be an absolute weapon on small shallow gold, would be a pellet lover too though 🙂

I wasn't interested with the legacy GPX models in this revelation, but with the extra sensitivity of the Algo it seems like a cool thing to try.

One thing I'd recommend, if possible, for people buying second hand coils for the Algoforce and only really if they're unusual coils like the ones demonstrated in Steves post above for the TDI or the probes is to test them on the detector before buying, I've had no trouble with any Coiltek, NF, Minelab or standard spiral X-coils.

When you plug in a new coil and go into the coil menu you have a number of slots you can save coil profiles on so you can have your favourite coils in there calibrated and ready to go, a new coil plugged in unless within the specifications of another coil you have used will request calibration.   It's a quick process, only takes a few seconds where you press the + and - buttons to start the calibration.  If a coil is too wildly outside of normal GPX specifications it won't calibrate, and if it won't calibrate, you're not getting the best out of the coil, it will work, but not as well as it could.

In all the coils I've got only a prototype 15" Concentric X-coil won't calibrate at all, and that's likely because it's a 15" Concentric in DD mode on the GPX and a 15" Spiral mono in mono mode, I think it's just too out of spec, this is being looked into to see if it can be resolved by either side as its not even a released coil.

I doubt many will encounter this and it would have to be some wildly bizarre or out of spec coil, if it does happen it just won't calibrate, you can still use it, it just may not work as well as if it was able to calibrate, although with my 15" CC that doesn't calibrate, I think it's working well on my initial usage.  

[Gerry in Idaho]

I had already thought of what Steve mentioned as I know Minelab, CT and NF's all have the 1/2 coil option.  Yes, I too feel the 10" Ellip DD will be killer.

[dig4gold]

48 minutes ago, phrunt said:

One thing I'd recommend, if possible, for people buying second hand coils for the Algoforce and only really if they're unusual coils like the ones demonstrated in Steves post above for the TDI or the probes is to test them on the detector before buying, I've had no trouble with any Coiltek, NF, Minelab or standard spiral X-coils.

Another good reason to test a 2nd hand coil before buying is that it may be getting sold because it has developed issues. I have been down that track.

D4G

[GeoBill]

How do you think the miner John/Razerback folded mono coils would perform? He made some very small ones. I don't remember if it was resolved, but was the "Hi-Q" coil that Whites was selling with the SL after Miner John's place burned, White's attempt at a folded mono?

[Steve Herschbach]

47 minutes ago, GeoBill said:

How do you think the miner John/Razerback folded mono coils would perform? He made some very small ones. I don't remember if it was resolved, but was the "Hi-Q" coil that Whites was selling with the SL after Miner John's place burned, White's attempt at a folded mono?

No way to know without trying them. I’ve never really been a fan of the dual fields or folded mono coil, preferring a straight up mono myself. These coils are attempting to solve issues with edge sensitivity, which is exactly what I like about mono coils. The Hi-Q was just an attempt to sell dual field under a new name as far as I know.

 

 

[RONS DETECTORS MINELAB]

Just glad we can use DD’s also now on the Eforce, this thing keeps surprising me on more good features. Running DD’s in mono mode is great, especially when we don’t need cancel mode as it seems to handle EMI well.

[karelian]

The question of Tdi coil compatibility delights the imagination. The AlgoForce makes good sense already and the use of existing coils is just another bonus. The little 6 x 4 mono would be an interesting match that would make for a feather weight combo.