Sheppo Posted March 19, 2021 Share Posted March 19, 2021 What’s the difference between a concentric coil and a normal coil? Just can’t seem to picture the windings in my head is all. (I understand the DOD, Mono and DD coils) Link to comment Share on other sites More sharing options...
Northeast Posted March 19, 2021 Share Posted March 19, 2021 Well done JR, gold on the scales is the goal. 2 hours ago, Jonathan Porter said: solid 13 gram to 20 gram mark, Difficult will actually outperform Normal on those, so it pays no matter how quiet the ground is to go back over it again to make sure you don’t miss out on the decent 1/2 ounce bit. Further to what JP has indicated, do you plan on going back over the same ground to see if there are any larger pieces lurking? Link to comment Share on other sites More sharing options...
AussieMatt Posted March 20, 2021 Share Posted March 20, 2021 3 hours ago, Sheppo said: What’s the difference between a concentric coil and a normal coil? Just can’t seem to picture the windings in my head is all. (I understand the DOD, Mono and DD coils) 5 Link to comment Share on other sites More sharing options...
mn90403 Posted March 20, 2021 Share Posted March 20, 2021 JR, Great job. Is Reg swinging one also or has he tried yours? Are they going to make a CC that size for the GPX/QED? Now the drawing above shows only signals below the coils. This would be the maximum pinpointing from my understanding. Before you get to the pinpointing you can hear a target before it is centered. If you had to estimate some of your finds so far with this coil can you hear the targets before they get under the coil? If I am swinging slowly or sometimes fast with a coil I can tell when I'm getting near. I will hear that 'off coil/fringe' sound and try to make it louder. I think we all do it so that makes your 22" coil really a 26" coil or more, right? Mitchel 1 Link to comment Share on other sites More sharing options...
geof_junk Posted March 20, 2021 Share Posted March 20, 2021 Note the field shown is the receive RX field how ever the transmit TX signal also has an effect on the responds of the coil and pinpointing. 3 Link to comment Share on other sites More sharing options...
jrbeatty Posted March 20, 2021 Author Share Posted March 20, 2021 23 hours ago, Northeast said: Well done JR, gold on the scales is the goal. Further to what JP has indicated, do you plan on going back over the same ground to see if there are any larger pieces lurking? No NE, I'm happy my settings got all that was available on the ground I have covered. I have done exhaustive tests on the Maryborough and Laanecoorie test sites with Tony Honey (who has had long experience with GPX concentrics) as well as undug gold targets in situ, I'm satisfied there are no "holes" in the settings I am using. 1 Link to comment Share on other sites More sharing options...
jrbeatty Posted March 20, 2021 Author Share Posted March 20, 2021 16 hours ago, mn90403 said: JR, Great job. Is Reg swinging one also or has he tried yours? Are they going to make a CC that size for the GPX/QED? Now the drawing above shows only signals below the coils. This would be the maximum pinpointing from my understanding. Before you get to the pinpointing you can hear a target before it is centered. If you had to estimate some of your finds so far with this coil can you hear the targets before they get under the coil? If I am swinging slowly or sometimes fast with a coil I can tell when I'm getting near. I will hear that 'off coil/fringe' sound and try to make it louder. I think we all do it so that makes your 22" coil really a 26" coil or more, right? Mitchel Mitch: Reg is swinging a Detech 18" concentric on his GPX As the illustrations posted show, you have to be over the target to hear it (big surface junk excepted) Therefore it follows that only the two central windings receive, so my 22" coil is in reality only an 11" one (approx) 1 1 Link to comment Share on other sites More sharing options...
geof_junk Posted March 20, 2021 Share Posted March 20, 2021 JR one of those two coils is a bucking coil which counteract the transmitting coil. Have anyone tested the coil in mono mode and what the results are. Link to comment Share on other sites More sharing options...
10fp Posted March 20, 2021 Share Posted March 20, 2021 the 18 Detech CC on the GP3000 is Bloody fantastic in Mono 1 Link to comment Share on other sites More sharing options...
jrbeatty Posted March 20, 2021 Author Share Posted March 20, 2021 33 minutes ago, geof_junk said: JR one of those two coils is a bucking coil which counteract the transmitting coil. Have anyone tested the coil in mono mode and what the results are. Geoff: It's my understanding that the Z concentrics have twin active central windings (as do the DOD standard coils but a different layout) The coil internals are a trade secret. But an x ray would be revealing - Link to comment Share on other sites More sharing options...
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