RELIC HAWK

[Max]

+VCC=+12V unregulated...
Fred.

Hi,
yes, unregulated... but is not a big problem in this case... cause op amps used have large immunity from such problems...like slow supply variations I think that with a fully charged 12V lead-acid battery you'll never find circuit unstable cause of voltage variations.

The 27Mx is really stable thing and have not much troubles dealing with slow variations at supply rail... the CMOS stuff will be also really stable too and good for the purpose.

Sure... if you use some small cells pack you could be lost into troubles... but I think this is not a real problem too... you could e.g. use a couple of cells more and then a regulator for 12V like 7812.

Actually I think RH have really more consistent stable approach than many other circuits we saw already.

Kind regards,
Max

[Fred]

Hi Max,

Don´t you think the lack of regulation could be a problem for the oscillator stage?

Regards,
Fred.

[Geo]

Hi Max,

Don´t you think the lack of regulation could be a problem for the oscillator stage?

Regards,
Fred.

Hi Fred.
With the unregulated voltage we will have a small frequency shift (when voltage is low) but i think that the phase shift will be stable (at large degree).
Regards

[Max]

Hi Max,

Don´t you think the lack of regulation could be a problem for the oscillator stage?

Regards,
Fred.

Hi,
no, I think oscillator little variations are not so important... also the oscillator here is different from e.g. Tesoro's that employ very classic configuration of colpitts' one. Geo is probably right that phase variations will be very small comparing RH with other designs.

I will be not surprised of very hi stability on lead-acid cells... like happens with some PIs too that have unregulated 12V rail. I think the interesting part of circuit is, apart oscillator stuff, the op amp chain... preamp+integrators other things , though essential are really close to other designs and so not better than that.

I think RH will have at least same , but probably more stability that a very good homemade TGS an no chatters at all.

The fact ML decided not putting 12V regulator there let me think it's absolutely unuseful in such a design.

I don't know about detph comparision but seems to me the osc stage will play important role, so probably good gain, over tesoro's designs on same coil dimensions... real data we could collect just making it!

Kind regards,
Max

[Fred]

Hi,
Thanks for answers!
I am beginning the PCB.
Some observations:
-The capacitor in // with the TX coil is 1uF ??!!
-U13 has only one gate used , i suppose unused pins are left unconnected .
-I dont think i will be able to make it single side, but i will try to keep this as an option ,that can be compensated by wirings.
-I will assume that the inductor connected in serie with the RX coil is the size of a 0,5W resistor.

If you have any comment on this or other part please let me know.

Regards!,
Fred.

[Geo]

Hi,
Thanks for answers!
I am beginning the PCB.
Some observations:
-The capacitor in // with the TX coil is 1uF ??!!
Yes (Coinseeker has the same)
-U13 has only one gate used , i suppose unused pins are left unconnected .
Yes
-I dont think i will be able to make it single side, but i will try to keep this as an option ,that can be compensated by wirings.
Personally i have not problem if it is a double side pcb
-I will assume that the inductor connected in serie with the RX coil is the size of a 0,5W resistor.
I believe that it is enough

If you have any comment on this or other part please let me know.

Regards!,
Fred.

Hi Fred.
I did not find errors yet. So i wish you good luck with the pcb.
I am sure about the quality of your pcb drawing
Regards

[Max]

Hi,
Thanks for answers!
I am beginning the PCB.
Some observations:
-The capacitor in // with the TX coil is 1uF ??!!
-U13 has only one gate used , i suppose unused pins are left unconnected .
-I dont think i will be able to make it single side, but i will try to keep this as an option ,that can be compensated by wirings.
-I will assume that the inductor connected in serie with the RX coil is the size of a 0,5W resistor.

If you have any comment on this or other part please let me know.

Regards!,
Fred.

Hi,
U13 is 4024, so counter not gates there... but yes just 3 relevant pins used + supply.

All the rest seems OK to me. If you can, avoid upper traces and go for jumpers on the upper side: many people can make here very nice single sided PCB with lot of jumpers if needed but just a few can do good a complex double sided one.

This is not a problem for me... I have double sided quality presensitized boards... but could be real trouble for those who haven't and this will complicate and slow down the cooperative work on this thread.

Anyway... if you see too complex... do it double sided.

PS: don't forget decoupling caps... are important in RH.

Kind regards,
Max

[Fred]

Thanks both!,

Yes i will try the single side board, but the problem is the supply rails and
decoupling caps,so i will have to make them on the upper side :i will let option by flying wires,jumpers or by PCB, not sure yet.
For decoupling caps they need to be short so the best way will probably be to solder them directly under the PCB
Also if i dont make it compact it will end as a quite large PCB, not easy to put inside case.So im a trying to make it high density.Hope it will not give problems.
Geo, it will be a messy ugly PCB .And full of mistakes.
I wish i had more time to work on it...
Regards!,
Fred.

[Geo]

Hi Fred.
No problem if the pcb is ugly, .... if it works fine!!!!
But i am afraid that if it is high density it will have problems from noise or from the oscillator or.......
So you must try the osc to be far from the front end stage.... audio etc....
But i believe that you know better than me
Now about the "I wish i had more time to work on it", never mint, slowly.... slowly and regularly
Regards

[Geo]

[quote=Max;73169
All the rest seems OK to me. If you can, avoid upper traces and go for jumpers on the upper side: many people can make here very nice single sided PCB with lot of jumpers if needed but just a few can do good a complex double sided one.
This is not a problem for me... I have double sided quality presensitized boards... but could be real trouble for those who haven't and this will complicate and slow down the cooperative work on this thread.

Anyway... if you see too complex... do it double sided.
Max[/quote]

Hi
I am not so good at the pcb construction (i am a little lasy) but no problem if it is double sided. The reason is that the protel_99se that i work dont make single side pcb. Anyway Fred try for the best
Regards

[Fred]

Size of PCB :9X12Cm
Fred.

[Geo]

Size of PCB :9X12Cm
Fred.

Special!!!!!
For me there is not problem until 9.5x15 cm because we can find 2 side pcb.

[Max]

Size of PCB :9X12Cm
Fred.

Cool ! What about troubles if any!?

I will do anything if say 10x16cm double side... for more large I just need make my own stuff cause haven't ready at the moment... I think could make also 20x20cm if needed , double sided... but no problems if it's just 9x12!

COOOOOOL!

Kind regards,
Max

[nakky]

7.5x14cm

[nakky]

Sorry single side.Grt Nakky.