RELIC HAWK

[porkluvr]

Too slow?

If I understand your problem correctly the RC network at the comparator input may be the problem. You could try reducing either component by a factor of 2, 5, 10, who knows. Lets say 5. Change either R to 100k or change C to 20n.

Here's something better: the diode should be connected to the RC junction instead of the comparator output?

[robopatt]

You are right Porkluvr.The old one shows 700n!!Maybe I overheated or some short.
Now its working good.
Almost.
The shuting between targets is not good enough.Too slow.

[porkluvr]

No, it was just a cheap joke...sorry

I can make some BS sometimes, without meaning to. You don't have to be sorry. I can take a joke. grrrrrr [just kidding] grrrrr
You cannot make an omelette without breaking some eggs. (That's a CHEEP joke.)

I will try 700 as you sad before.

You misunderstand my meaning. I was suggesting that your capacitor may be 700nF which is bad. I was not trying to suggest that you should use a bad part. 700nF would account for the oscillator being off frequency by almost 20%.
ummh, Have you measured the value of the capacitor that you had at first? Why not?
**********************
Funny thing about this oscillator is that at 5kc it's a power sucking pig, but after bumping up to 20kc, appears to be very reasonable. I fiddled with the parts and through trial and error found a combination that gives high output and low distortion, with low(ish) power consumption. Hmmm. Good thing I never finished that other thing I was working on. This should be included.

If LTspice can be believed this absolutely blows the Tesoro Lobo oscillator out of the water AND it requires NO adjustment. Installing a TL061 opamp reduces supply current to about +/- 3.5mA. It's a bit higher with an 071 (or 081).
I will get some data together and probably make an informational post over in the "Lobo Improved" forum within a day or two.

[robopatt]

Porkluvr,
Now I have used plastic 1m .
Use DL6243 shows 1m.
Frequency is now 4,85.And performance is just good now.
I attach 150ohm speaker.Good
Now I have to match my RX resistance and inductance because they are low.
You were right when you say that we will face problem whit power.Its eating the battery in no time.

[Fred]

I think Fred was trying to suggest that my idea about frequency jitter was far fetched. I hope so!

No, it was just a cheap joke...sorry

[robopatt]

I agree with you Porkluvr.
You have a point.
I will buy one scope ASAP.

But have try your advice.Have used 1m 100V Polycarbonate Capacitor.
Now frequency is 4,66kHz.
Disc mode little bit stable.But still this poor sens.
I will try 700 as you sad before.

Forget to mention that I have changed D2 joint between 27k and Q1.
Q3 base changed between 10K and 27K.
Have took this 100k between Q2 and Q3 and solder under PCB on Q2 base and Q3 collector.
I am almost 100% shore they should be this way.

But you will tell when check with LT.

And because no one with scope have done this its a small but progress

[porkluvr]

Small yellow ceramic with 105 label.

Owww.

You should use a high quality 1uF cap. Two high quality .5u in parallel is just as good (if they fit) but please do not use ceramic cap!
Polyester (mylar) will probably work but you really REALLY should use polypropylene for the tx tank. PP is low loss and temperature stable. Mylar is inexpensive, and I don't know that Minelab doesn't use that here - but I wouldn't. PP are kind of big so use 50V to 100V unit. Stay away from more common 250V or 400V because they get really big.

If you come across Polycarbonate, they're maybe second best - but don't waste time trying to find them because they're mostly (or maybe completely) discontinued.

You will almost certainly need an oscilloscope. I know it's been done before, but I think that it's crazy to expect to have a successful project without one. You'd have to be very lucky or else very smart and experienced.

I think Fred was trying to suggest that my idea about frequency jitter was far fetched. I hope so!

[robopatt]

Porkluvr,

Have you measured the 1uF parallel capacitor in the TX tank?
No I haven't.Just put one there.Small yellow ceramic with 105 label.
I will try change it.

Have you measured the TX coil, or did you assume that you wound it correctly?
Yes I have measured this and it shows 1mH.

Sorry I don't have a scope.Hope get one soon.

[Fred]

....(Scope, what's that?) Yeah, me too.

This is a scope:



with this you can see small jitter in a waveform from far away

[porkluvr]

I have tested with good coil.A little bit better.
...frequency is 6.0kHz with original coil..

Another possible explanation for incorrect frequency reading: if TX coil and capacitor are very close to optimum values there could be something else causing waveform jitter with a frequency component being picked up by your freq meter. If you have a scope you should be able to see it.

(Scope, what's that?) Yeah, me too.

[porkluvr]

Hopefully i will get one soon.

It's not important but it would satisfy curiosity "exactly" what is that part.
I know a few things what it aint!

[ivconic]

Ivconic, if you (or anyone) get the chance please tell the SMD code on the unknown transistor. Most SMD code directories are not complete (and sometimes ambiguous) so there's no guaranteed lookup, but there is a chance that Marsport.org or somebody will have it listed.

If that doesn't work, manufacturers' data sheets usually list the SMD codes that are printed on their devices. There is a chance somebody will run across it in a product data sheet.

NXP BC807-40 is "5Cp". Did I get lucky? (fat chance)

Yes i understand you. But at few devices i saw so far, there wasn't any label... Just blank!?
Right now i don't have any device at me. Hopefully i will get one soon.

[porkluvr]

I'll try again.
Robopatt,
I don't want to appear hostile, but the information you gave seems illogical, and yet you seem so sure of yourself. That's frustrating.

Then tank is the parallel LC network including the TX coil. Anybody wanting to assist you would need to know the values of your tank capacitor and tank inductor. Those are the frequency determining devices in the transmit circuit.
Using 1uF and 1mH, to calculate frequency:
F=1/(2pi(sqrt(LC)))=5000

Working backwords from that formula, (or having related formulas on hand, which is much easier) something is bad wrong if you have 6000. You would either need a 700uH coil or a 700nF capacitor to get there, or those two components could both be half that bad. It is not a trivial error, and the detector will very likely not work right until that is fixed.

If you have not measured your coil then you should not bluntly state that it is 1mH. You can't know with any degree of accuracy without measuring, or unless you have measured another one exactly like it. Maybe I'm wrong, but it seems to me that if you have a means to measure the tx coil and the tx frequency, then you would probably also have a means to measure the capacitor because I believe capacitance meters are more common than inductance meters. But, there's no guarantee.

I asked if you measured the capacitor. Forgive me for not being more specific, but I assumed you would know which capacitor I was referring to. I thought it would be obvious that I wanted to know about the capacitor that determines frequency. It should be 1uF (+/- 5%), assuming 5% tolerance.

Have you measured the 1uF parallel capacitor in the TX tank?
Have you measured the TX coil, or did you assume that you wound it correctly?

Five percent error in your output frequency may be OK, but you have almost 20% error That is not good.

Guest

I now who I am and post with my name.But why you don register or use your name here and then make funny conclusions.I am not taking your words serious.
And not offend but I can TIKTAK your mother!!!
If my skills are not on your level you cant just spit worlds.
Simple description would do the job just fine.Or just keep acting silly.

Yesterday, 10:28 PM
robopatt
Junior Member Join Date: Mar 2009
Posts: 26

TRS coil

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I need larger coil for Tesoro Royal Sabre.
Have old DD17,5 this is 8'' I think.Its widescan DD.
I wanna make lets say 27,30 DD.
The strange thing is that all pins on coil buxe make contact when tested???
How is this wired actualy?
This original one have such datas 5,71 mH /20,5 ohms and 5,60mH/20,3 ohms.

02-20-2009, 10:00 PM
tiktak
Guru Join Date: Jul 2007
Posts: 516

Hi,

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Hi,
Ectremly small coil 8''=17,5cmDD.
Weight is 319gr.The sound is diferent from TGS but and coils are.
Can somebody tell me is that on molzars picture royal sabre or royal sabre plus?
What are diferances?
Thanks
p.s.So now I am very happy from TGS and TGSL results!
Hahah

1 inch = 2,54 centimeter 8x 2.54=20.32 cm

[robopatt]

I now who I am and post with my name.But why you don register or use your name here and then make funny conclusions.I am not taking your words serious.
And not offend but I can TIKTAK your mother!!!
If my skills are not on your level you cant just spit worlds.
Simple description would do the job just fine.Or just keep acting silly.