Tesoro Lobo news

[Davor]

Both TLC27M2 and LF442 suck at 1/f noise. They are precision op amps, and perhaps they would perform better than a lower noise option in a quasi non-motion circuit as they are, but again, maybe not. LF442 is a bit quieter, but I'd try TL072 instead. TLC27M2 has 300nV/sqrt(Hz) at 1Hz and with a gain of 47 it greatly exceeds offset capability of this chip. Hence chatters.

I revisited the conversion to Eagle idea, and, well, it just won't work in this format. I tried copy/pasting from PCB-Pool version of Target to a free but limited version that can convert to eagle script, but the limits get exceeded at ~50% of this design.

[Davor]

Regarding compressor, I'd try this configuration:

[technos]

Both TLC27M2 and LF442 suck at 1/f noise. They are precision op amps, and perhaps they would perform better than a lower noise option in a quasi non-motion circuit as they are, but again, maybe not. LF442 is a bit quieter, but I'd try TL072 instead. TLC27M2 has 300nV/sqrt(Hz) at 1Hz and with a gain of 47 it greatly exceeds offset capability of this chip. Hence chatters.

But does that noise 1/f become relevant anywhere in this circuit? Signal from Rx loop is probably 1000 (guess) larger. I.g. 50 mV signal on loop compared to 2 nV 1/f noise.

[technos]

Regarding compressor, I'd try this configuration:

That's a great idea! But then that's a clipper - You need to preserve the gain of 100 which it may not have with the diodes as configured. Back to back zeners with a resistor makes more sense imho. But this takes care of the turn on noise, but not the "sensitivity" problem (as far as I can tell).

[Davor]

1/f noise is relevant because with these gains and noise, it appears in mV values already at the output of LF442, and it is a dynamically changing component, same as targets, hence chatters. Air signal is cyclostationary and only AM noise on top of carrier may pass through, and that's why Tx noise performance, and power supply filtering matters. With good induction balance both cyclostationary carrier, and the offending AM noise are diminished, so that's one of two reasons to go for a better IB.

A compressor with diodes, or a clipper as you noticed, provides log function over the input signal, and it's output is + and - 0.5V or so. Being a part of a non-inverting amp, it is a soft limiter, as the non-inverting amp can have a minimum gain of 1. For small signals it provides full gain of 100.

I noted that this kind of limiting makes for much softer experience of targets than without a limiter, and the loudness is much closer to our perception of proximity than the raw signal, which is too sharp.

There is a potential to distribute gain somewhat differently to better use compression, and my drawing is just a suggestion of the possible course. Because of only 0.5V swing my suggestion would not give much loudness. A better way of doing compression would require reducing gain in this stage from 100 to 10, increasing gain of the previous stage more than 10 times and introduce compression there. It works beautifully with IGSL.

[Fabian]

Hello Legaucho. I wanted to ask you if you could give a short review of the performance of Luba Compact talking about stability, detection depth etc, as well as any problems you have noticed in your field use, or if there is still an unresolved problem for Normal operation.

Thank you in advance,

Fabian

[Legaucho]

Hello Fabian. Concerning the LuBa I don't any other news except those in this topic. After having tried to make it work ideally, I confess that I went on to something else, realizing that the King Cobra also has a problem Mode "All Metal". The Luba works but its performance remains to develop (ideal for electronics expert I am not.). There are no wiring or shematic errors, maybe just a few adjustments to components.
Sorry can not help you more. All the best

[Fabian]

Hello Legaucho. Now I have more clear what I sensed. I'm not an electronics expert either (just a hobbyist) so we have to expect that those who know, "talk" about this very interesting project. I regret not being able to speak Russian, because it seems that the Russian site project is running, and google is not enough to follow the thread of that forum.

Regards,

Fabian

[Kev]

Hello Legaucho. Now I have more clear what I sensed. I'm not an electronics expert either (just a hobbyist) so we have to expect that those who know, "talk" about this very interesting project. I regret not being able to speak Russian, because it seems that the Russian site project is running, and google is not enough to follow the thread of that forum.

Regards,

Fabian

Hi Fabian,
Have you tried Google Chrome, apparently it has a built in translations feature?
I'm using Linux online and have not been successful loading a distro yet, your post has prompted me to try again.

Cheers
Kev.

[Qiaozhi]

Hi Fabian,
Have you tried Google Chrome, apparently it has a built in translations feature?
I'm using Linux online and have not been successful loading a distro yet, your post has prompted me to try again.

Cheers
Kev.

I'm using Linux with Firefox. Try using the Bing Translator -> http://www.bing.com/translator/

[Kev]

I'm using Linux with Firefox. Try using the Bing Translator -> http://www.bing.com/translator/

Thanks Qiaozhi, that's one I'll bookmark.

The reason I'm wanting to install Chrome onto my odd OS (Ubuntu derivative I think?) and suggest Fabian try also, is that you don't need to copy and past the text you're interested in, it's meant to translate the whole page as it loads. This would effortlessly open up many more forums to us.

Cheers
Kev.

[Kev]

Hi, I went away and tried again and managed to install Chromium (Linux version of Chrome) seemed I needed to search the correct repositories for the latest version.Anyway I just went to the Russian site hosting the Wolf project and at the top of the page is a bar which say "Translate page" when I clicked on that it quickly appeared in English.A nice clean browser too!CheersKev.

[Kev]

Hi, I went away and tried again and managed to install Chromium (Linux version of Chrome) seemed I needed to search the correct repositories for the latest version.Anyway I just went to the Russian site hosting the Wolf project and at the top of the page is a bar which say "Translate page" when I clicked on that it quickly appeared in English.A nice clean browser too!CheersKev.

Oh, seems there's a compatibility issue with Chromium and Geotech Board, slow and missing functions in the interface.

I suggest browsing Russian, French, Spanish etc., MD forums with Chrome, but contributing to Geotech in Firefox, I.E etc., Best of both worlds.

Cheers
Kev.

[Fabian]

Translation

Oh, seems there's a compatibility issue with Chromium and Geotech Board, slow and missing functions in the interface.

I suggest browsing Russian, French, Spanish etc., MD forums with Chrome, but contributing to Geotech in Firefox, I.E etc., Best of both worlds.

Cheers
Kev.

Hi Kev. Thank you very much for your suggestions. I currently use Firefox on OSX and Windows. I translate complete pages directly in google (http://translate.google.com/) putting the url in the first box and translates that url and from which is already translated, the following. The problem is that the level of translation (at least from Russian into Spanish) is very bad and generates a confusing text, which for technical issues is bad too. I will try from Russian into English.

Returning to LOBO, I got these files on the Russian forum and I think are interesting.


Regards,

Fabian

[ZL17]

Hello! I'm Polish and I know very little English and so sorry for any mistakes (I am using a translator). Does anyone have a schematic bilateral Fellow Lobo plate format such as pdf or doc? Many thanks to the interest and all the answers.