TESORO GOLDEN SABRE

[Max]

Just finished center tapped coil for TGSL...
Wow! Never mind the "depths" in the air, it is not what i want to say here...but phase behavior!!!? Wow!
Quite different than with pevious coils..!
I dont want to tell stories here, just want to suggest you to asap make center tapped coil, and see with your own eyes..
I am in the middle of experimenting and examing recent setup..be back soon..
Cheers!

Hi,
I see... but what about the depth in air ?

I'd like to know them too...

Kind regards,
Max

[ivconic]

Just finished center tapped coil for TGSL...
Wow! Never mind the "depths" in the air, it is not what i want to say here...but phase behavior!!!? Wow!
Quite different than with pevious coils..!
I dont want to tell stories here, just want to suggest you to asap make center tapped coil, and see with your own eyes..
I am in the middle of experimenting and examing recent setup..be back soon..
Cheers!

[ivconic]

In some simulators TGSL oscillator will not start to oscillate at all !!!
Still it is working from a start eachtime i finish another one and switch ON.
So...simulators "...are good for absolutelly nothing!"
Joking of course, Max is right, some parameters are not set up..

In LiveWire it will not start at all? Yesterday i tried...no results!?


http://rapidshare.com/files/51075143...1_Pro.rar.html

[Max]

Hi friends
This is SPICE analysis of OSC section of TGSL-1265 with all associated loads.
Tx signal is not stable with loads but without loads it becomes stable.
What is the problem?

Hi,
you must always consider the internal series resistance in the coil models. The instability is probably due to a wrong simulation param.

In my simulation the tx signal appears almost stable in amplitude.

Kind regards,
Max

[wild_desert]

PSPICE Analysis of TGSL-1265

Hi friends
This is SPICE analysis of OSC section of TGSL-1265 with all associated loads.
Tx signal is not stable with loads but without loads it becomes stable.
What is the problem?

[Fred]

Thi is why we can get incredible sensitivity with some coils, when the get almost tuned, but with lots of stability problems..
LC meter is a must have
Regards,
Fred.

[Max]

Yes Cx is approx. 20nF ( 21.xx) so as i posted in previous post.

About RX...no i am not connecting RX LC to TX output to measure Freq.
Simply i got 16.xxkHz from calculation, taking L and C values from presented RX setup..

Hi,
yes, now I understand, sure you're right about it.

If the inductance is 6.2mH (like often in tesoro's coils for that detectors) one will get around 16.5Khz using the 15nF cap there.

That's about 2Khz up than tx frequency...so far enough to be resonant involved.

Kind regards,
Max

[ivconic]

Hi,
RX is 16.1KHz ?

About TX, 14.6Khz is really cool at it: in Colpitts' oscillator the resonant tank is made by 2caps and the inductance.

The formula is :

f = 1/(2*pi*sqrt(L*Cx))

where Cx is due to the 2 caps there --> Cx = (C1*C2)/(C1+C2)

So... it's the lowest value one that dictate the frequency... with the influence of the larger one.

In TGS, at operating frequency, the tank is like made by the L and a 21.80nF cap.

So if the TX inductance is e.g. 5.45mH we'll get the 14.6Khz.

Now... I have to say that in my original coil I read not 5.45mH at TX but around 5.85mH that gave me about 14.1Khz on TGS.

But this is for the spider 9x8''... other coils are maybe different. I think spider coils by Tesoro have larger inductance at TX and lower at RX...maybe due to assembling procedure they use there...

Not to say that the 5.45mH coil (my fabulous homemade DD) works much better than the original Tesoro coil... same for my old 22cm DD... better also than the 9x8''. I found it good performative just on bandido... on TGS is just a very average coil.

PS: if you connect RX to oscillator you'll get lower frequency cause there's more inductance... so why you read 16.1Khz ???

Kind regards,
Max

Yes Cx is approx. 20nF ( 21.xx) so as i posted in previous post.

About RX...no i am not connecting RX LC to TX output to measure Freq.
Simply i got 16.xxkHz from calculation, taking L and C values from presented RX setup..

[Max]

Yup! Finally TX is 14.6kHz and RX 16.1kHz. TGSL TX LC is not parallel. There are 0.22 and 0.022 in emittor forming actually 20nF capacitance parallel to 6mH inductance..giving approx. 14.xxkHz.
I was seriously thinking to make ceneter tapped RX coil. Have expectations that it will give better performances..

Hi,
RX is 16.1KHz ?

About TX, 14.6Khz is really cool at it: in Colpitts' oscillator the resonant tank is made by 2caps and the inductance.

The formula is :

f = 1/(2*pi*sqrt(L*Cx))

where Cx is due to the 2 caps there --> Cx = (C1*C2)/(C1+C2)

So... it's the lowest value one that dictate the frequency... with the influence of the larger one.

In TGS, at operating frequency, the tank is like made by the L and a 21.80nF cap.

So if the TX inductance is e.g. 5.45mH we'll get the 14.6Khz.

Now... I have to say that in my original coil I read not 5.45mH at TX but around 5.85mH that gave me about 14.1Khz on TGS.

But this is for the spider 9x8''... other coils are maybe different. I think spider coils by Tesoro have larger inductance at TX and lower at RX...maybe due to assembling procedure they use there...

Not to say that the 5.45mH coil (my fabulous homemade DD) works much better than the original Tesoro coil... same for my old 22cm DD... better also than the 9x8''. I found it good performative just on bandido... on TGS is just a very average coil.

PS: if you connect RX to oscillator you'll get lower frequency cause there's more inductance... so why you read 16.1Khz ???

Kind regards,
Max

[ivconic]

Hi,
I meant that RX tank must not be resonant with TX tank frequency. You have it a little displaced in resonant frequency from resonant frequency of tx tank. This means rx works out of tx resonance, in a way it's easy getting the signal but cutting some unwanted effects (expecially about stability) that show at TX-RX resonant designs.

Kind regards,
Max

Yup! Finally TX is 14.6kHz and RX 16.1kHz. TGSL TX LC is not parallel. There are 0.22 and 0.022 in emittor forming actually 20nF capacitance parallel to 6mH inductance..giving approx. 14.xxkHz.
I was seriously thinking to make ceneter tapped RX coil. Have expectations that it will give better performances..

[ivconic]

Hi, you posted this a while ago but I am interested...

What was the problem with each IC? Poor depth, stability? Can you say how much depth you lose chosing different ICs if used with your latest TGSL design?

Who's gonna remember all the wild things i ever tried with TGS!?!?!
I dont remember details at all.
I remember CA3130 worked so,so. NE5534 was very poor there. 741 worked "sharp" but weak...TL081 is only good replacement i have found so far.
I can not find LT's in local shops, so never tried.

[eclipse]

All OA in this design are old, low CMRR, high input noise, etc.
I also consider to experiment with different parts, thats why i just
ordered bunch of OPA's, LT's along with wima caps, precise resistors (10uV input noise). I wonder if there will be any improvement.
Cheers

[Max]

What is meant by "non-resonant"? There is capacitor C6, which should be resonant with RX coil at about 16.3 Khz. Do you mean coil by itself should not self-resonate at 16 Khz?

Hi,
I meant that RX tank must not be resonant with TX tank frequency. You have it a little displaced in resonant frequency from resonant frequency of tx tank. This means rx works out of tx resonance, in a way it's easy getting the signal but cutting some unwanted effects (expecially about stability) that show at TX-RX resonant designs.

Kind regards,
Max

[simonbaker]

LT1008 should be good replacement for LM308, therefore LT1012 should replace 2 of LM308 put togather in this schematic...noted as TL082....
I tested TL081 and later TL082 and those working erratic, producing to many "blah,blah..." in speaker when Sensitivity pot is over 50%.... Bad choice....
Also tested: 741,LM318,CA3130,CA3140,1458,4558,LM301,LM311,NE55 34.....
None of those can replace LM308 in this design!
Interesting was playing with CA3130; depth was much greater than with LM308....over 40%....but works erratically when no target in coil proximity???
It should be reconsidered, might CA....be used with some surrounding components changed...? I am to tired of experimenting, also have 8 Goldy pcb's to finish these days...so i let you, guys to check CA3134/40.....
Regards!

Hi, you posted this a while ago but I am interested...

What was the problem with each IC? Poor depth, stability? Can you say how much depth you lose chosing different ICs if used with your latest TGSL design?

[wild_desert]

Thanks Amtech
Thanks Max

I will test may coil and inform you.
I like to know it before make it. I'm not a "Copier Machine".

Best regards