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The manufacturer hasn't brought out a 7" coil for the Blisstool yet and myself and other people are wondering if there is a 7" coil manufactured for another detector which would also work on the Blisstool. Is it enough to match the 8khz frequency and fit the right plug or is there more to it than that. Obviously, I don't want to waste money on a coil that just isn't going to work for technical reasons that I am not aware of and any guidance would be much appreciated.
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I've since found out it is more complicated thing than I thought. The RX and TX coil windings have to closely match when measured for ohm readings -
I guess no-one replied because no-one knows what the specs of the Blisstools' coils are, so can't say if they are close to any other commercial coils. But I wouldn't be optimistic, if I were you. Lots of things have to be correct: TX and RX inductance, and resistance, the freq that it's set up for (though there are 'broadband' coils,eg. Teknetics Greek series), the screening methods used internally, any additional components inside it (anything from a single capacitor, up to an entire amplifier circuit with copy-protection microprocessor [Minelab Xterra's] is possible).Comment
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to be fair there is not a great deal of love shown for the bliss, either here or or other forums(except the bliss forum which is the opposite, and where no criticism is allowed
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which is a shame as every detector has its fans and place, i have tried one at a rally, it was way too skittish,far too complex and way over priced imho but as some love it good for them.
my main gripe about the blisstool is the lack of a simplified cheaper model with a smaller coil, it seems that in uk they would have sold loads, a missed opportunity in my view, as for a smaller coil dont hold your breath, look how long it took them to admit the coil ears were weak on the first ones.Comment
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If this could help anything..... Ive got allso a Blisstool and been trying to make and help with this Small coil project...
My Bliss 11" coil got this data ; Bliss TX 2.9 ohm - 0.99 mH / RX 19.2 ohm - 8.95 mH.
There is no capacity built in the coil, and all is inside the control box. (385 nf capacity at the TX side)
The resonans Freq. COIL and BOX together is 8.1 khz at the TX side and the RX side are 43.5 khz.
The Q factor (If I'm doing this right) is Q 16 with a bandwith 470 hz.
It would Be a great help If somebody could say... Try this coil brand, the data is close the same..
The small coil project is not about depht, but only to use in Heavy iron infested areas...
Henrik.Comment
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if the coil has no tuning components then it should be relatively simple to match those coil specs in a say 7" coil, i find winding vlf coils a pain in the arse, to be fair the vlf projects ive played with have been with stock coils, but i have wound and built tons for pi and bfo.
but there are those who have it nailed on this forum and iv'e no doubt they could do it.Comment
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That doesn't sound right. It should be much closer to the TX frequency.Originally posted by Henrikras View Post
Is there a parallel cap across the RX coil (inside the control box)? If so, what's its value?Comment
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I'll will look inside tomorrow and do the test Once more..
You right its seem to Be high with 9 mH coil... Looks like no or Very small capacity !!!
Thanks for Saying this.
HenrikComment
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Hi again.
4 Stock coils has been tested.... The resonans RX side is high up! Strange. All 4 search coils got RX resonans from 48-50 khz. There is no capacity before the preamp.. (Maybee a Very small one 1 Nf but no capacity block like at the TX side)
LC / 8.6 mH x 1.2 nF = 50 khz...
Two 11" coils got 8.67 mH and two 15" coils got 8.50 mH at the RX side. 19 to 21 ohm.
The Gain pot. is 50 Kohm, and I can see the amplitude at the Scope is changing turning the GAIN pot. There is a 10 k ohm resistor between the GAIN pot and the RX signal, before it comes to the Preamp.
Dont know If this would help anything.
Henrik.Comment
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I always wondered what the insides of the Blisstool control box looks like, mind posting some pictures?
I thought to myself if I could find a Bliss cheap, missed out on a couple, might take a stab at making a 7" coil.Comment
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To you Sven... Some Pictures. VTC 48 and VTC 64.Originally posted by SVEN1 View Post
Ps. I know a guy with VTC 64 v3 - still warranty - prize 420-450 £ - both coils. PM If you want a contact to him.
Henrik.Comment
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I was just browsing and saw the pcb pic. Come on! All those pots ? Something that needs that kind of set-up is bad news. I have worked with lots of proto-type stuff made that way. What a nightmare it must be. How do you set it up, and I bet it drifts a bit. It looks 'orrible (IMO)
BUT I have nothing against analogue with lots of set-up automated by a decent CPU.Comment
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I couldn't believe there's so many trimpots inside to go along with the ones outside. Yikes!
Just a thought, if the detectors more or less perform the same , couldn't the resistance value of what the trimpots were set up at be switched out for a fixed value resistor?
After seeing all those trimpots, and claims of some Blisstools working incredible and others so-so (complaints) be related to mis-calibration of the trimpots? I'm sure there's more than one person calibrating
the Bliss at the factory...................Comment
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I dont set them up... Only buy them, use them.. And improve something. If I can find something there could Be done better.Originally posted by mykaitch View Post
I learned how the power supply, the preamp and the GAIN system is working, only because my first buy had some errors and I open it up... Tryed a lot and found the problem.
Later in the process I found out where the tone is Breaking up and made a two tone model.. But is wasn't perfect. It Helped a little.
honestly I do not know why I continue to believe in this beast of a Detector.. Maybee that I Once or twice had dig up a coin from very deep down with this Blistool ! I got Hooked..
Is a learning fase I'm through. Properly in one or two years I would look back and ask why ! and maybee think it was waist of time.
Henrik.Comment
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Sven you right... I can tell where the voltage can Be adjusted.. All the rest I got no clue.Originally posted by SVEN1 View Post
Some pot. must Be the disc. settings.. And that is a Big problem with this Detector.. DT, DL and DD... And I can tell you a secret.. Psss...dont tell Anybody
. The disc system is NOT Linearly... If you change the DT it got influence to the DL, and If I adjust the DL it allso change to DD... Nightmare to find the best setting... Just think about coke. !! If the coke is at surface you change the DT, but next coke is Maybee 2" down, then you must adjust the DL.. But third target is a deep small hammered and now the the DD is to high. !!
The tone is Breaking up.. But the breaking tone depent how deep your target is. NOT GOOD Sven.
Muddy Boots found a good idea... Find a small handheld Detector with a 4-5" coil, and use that to help you before you end digging down to China.
HenrikComment
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