Some folks may be interested in either of these 2 coils, or both actually.
How do they compare?
As far as relic hunting and yes coin hunting.
Today I did some careful testing and thought I would share with folks here.
I don't have gobs of time yet on round HF coil like I do the smaller HF elliptical.
Anyway with the HF coil being deemed high frequency some folks when they see or hear about this round coil may be thinking hunting gold nuggets only.
Well, to make a long story short here, the round HF coil based on my testing is the odds on favorite to sneak higher conductors out of iron and nails vs using LF coil.
The use of the lower freq band on the round HF coil centered btw at 14.4khz yields some awfully good results for such a big coil.
If folks thought the 9" LF coil was/is grand here for finding coins in iron and nails, the HF coil here yields significant advantage.
Higher conductors can be had too using the middle band of frequency centered at 28.8 kHz, but it is my opinion based on testing if a Deus user hunting a site hard using 28.8khz and tried to find all higher conductive coins, I think the site could be hunted again using 14.4 kHz and the possibility of additional high conducive coins be had.
One very noticeable thing with the round HF coil, Reactivty 4 yields a depth advantage (distance measurement between the planes (where coin and nail) for example lay vs 9" LF coil.
Many instances where use of Reactivty 4 on LF coil yield no signal on clad dime.
Also using round HF coil hunting in lots of iron, Reactivty 2.5 IMO yields poor results, better to use 3 or 4.
The thinking with original LF Deus coils were better unmasking to be had as highest freq approx 18khz, and this was/is still true.
Using 54khz (upper freq band) IMO based on testing, user looking for high conductors don't expect much detection on higher conductors as far as they existing beneath ferrous object plane.
Now I did do similar test with US nickel, and IMO strangely I think the differences (advantage noted) for round HF coil are less significant vs 9" LF coil. Still though a depth advantage using Reactivty level 4.
Now the testing above was done on a set of sterile concrete steps, with GB dialed on all testing to 84.
So these test don't really account for soil mineralization effects, but still I think these results do tell me some thing.
I sure wouldn't expect to see better results than I got if my test rigging was buried in say medium or higher level minerlized soil.
Now none of this above, it should be necessarily related to gold nugget performance.
A side note here.
Thus far using the round HF coil for me, in a couple sites pounded with Deus both 9 and 11" LF coils, not much has surfaced. I should point out these few sites have really never given up any high conductors like coins and all of my use of round HF coil has been using 28.8khz freq in these sites. After testing today I can understand the Why behind maybe why my nonferrous finds were lacking.
Just thought I would share.
By Steve Herschbach
Here are three detectors that offer three different ways to do multi-frequency.
First up, the detector on the right, the XP DEUS. This detector allows you to choose from one of four different frequencies, and run any single one at a time. You can choose from 4, 8, 12, or 18 kHz.
Second, we have the detector on the far left, the Minelab CTX 3030. This detector looks at a range of frequencies and analyzes several at once. Transmitted frequencies is a bit of marketing magic; all that matters is what a detector processes. The CTX 3030 processes two or three frequencies simultaneously, comparing the results with advanced algorithms to deliver target information. There is no option to process single frequencies.
Finally, the detector in the middle, the White's V3i. This detector employs three frequencies, and is unique in that it can process and compare results from all three simultaneously, or run any one single frequency. The choices are 2.5, 7.5, and 22.5 kHz.
In a nutshell low frequencies are less reactive to ground minerals and produce cleaner signals on coin size high conductive targets. Low frequencies also better discern ferrous from non-ferrous items. High frequencies are more reactive to ground mineralization and have more issues identifying ferrous trash, but respond better to small low conductive items. Frequencies under 10 kHz tend to be "coin frequencies", 10 kHz to 15 kHz is a good "all around frequency range", and over 15 kHz tends to be the realm of prospecting detectors, though higher frequencies are seeing more use now with others attempting to pull small non-ferrous items out of ferrous trash. European hunters looking for small coins and relic hunters looking for bullets and other items are leaning higher frequency these days.
Usually choosing a single frequency will deliver the most power and depth. That is why you do not see multi-frequency nugget detectors, and why out of the three detectors discussed here the Deus with its 18 kHz mode and V3i with its 22.5 kHz mode offer better potential as prospecting units than the CTX 3030. Detectors that process multiple frequencies have a clear edge when running on mineralized salt water beaches. A single frequency can handle the mineralization, or the salt effect, but not both at once. Multi-frequency detectors are the preferred solution for salt water beach applications (not counting PI detectors), and so the CTX 3030 and V3i have a clear edge over the Deus in this regard.
Multiple frequency analysis can offer superb discrimination capabilities. When people talk about depth on multi-frequency detectors what they are really talking about is accurate target identification at depth. Many detectors will detect deeper than the multi-frequency units, but not while delivering accurate target id results. The Minelab Explorers and CTX are generally acknowledged as being on the forefront in this regard, no doubt due to the highly secret algorithms they employ to deliver target id results.
Anyway, the three detectors here have three different ways of handling the options. In theory the V3i offers the best of both worlds - the ability to run any one frequency or three at once. In practice the V3i is so complex few people ever fully master its capabilities but I do think they have the right idea. A much requested idea for the XP Deus, which is updateable via software, is the ability to run multiple frequencies. On salt water beaches at least this offers an indisputable advantage. Presumably an update to the CTX could offer the ability to run a single frequency, but so far Minelab has shown no interest in such options. It does appear that is where we are heading though - detectors that through proper design and software can become most anything the operator desires.
I remember a thread where Steve H. was reconsidering the Deus in light of a yet to be released new coil option that raised the possibility of its use as a VLF gold detector for high trash areas. I searched the web and everything pointed to a summer '16 release, all silent since then. Just wondering if there are any new hot rumors out there, maybe Nevada Chris can give some insight.