BFO "Discussion"

[WM6]

Schematic I posted in my previous post is compilation between "Circuit 8" and "BEFF-O-MATIC" BFO posted on side:

http://www.patrickwarren.me.uk/beefomatic.html

There is to find one possible solution for mixer/amplification stage too.

Cannot say nothing about performances - not tested yet.

[Gwil]

Don't know if this is important, but the two 10k resistors connected to X create coupling between the two oscillators and might make it harder for their frequencies to move apart. This effect would be reduced if X was a low impedance point or if the Rx stage had two separate inputs. Just thinking aloud...

[pebe]

Thanks. Now you have drawn it logically, it now makes sense to me.

[Tim]

Gwil, if you are right, perhaps it would be better to stick with my AM receiver circuit? It seems to work good for me. As we know this type of receiver can receive multiple sympathetic frequencies, perhaps lending itself to the binaural signal suggested in the LF project, where I originally posted this.

[sinclairuser]

hi tim, if this simpler bfo technology is what interests you, in terms of developing it to something better, take a look at T SCARBOROUGH'S beat balance design.
it performs better than bfo designs and its coil coupling is non critical, so building and tuning its coils is easier than IB
http://www.zen22142.zen.co.uk/Circui...tgear/bbmd.htm ,

it as far as i know never been developed beyond scarborough's basic concept, allways fancied building a better more complex version of this but never found the time.

[Tim]

Yeah I have tried this one with LM348 as per Colin Mitchells site. I did not however try the LF347. I just took Colins' word that it did not work. From memory I couldn't get the LM348 to work. Another Scarborough circuit uses TL074, which I'm currently awaiting in the mail. I have also tried most of the designs using CD4001, CD4011, CD4013, CD4093, and CD40106.
So far those that have worked have not come within cooee of the Circuit8 IB/Beat Balance I made. That is not to say that they couldn't with coil experimentation.
As my DD coil was set and made on the Matchless that is my current reference point. The ground interference Scarborough overcame with an earthed faraday shield, I overcame (i think better) with shiny powdered milk packet, not earthed.
I have all my electronics packed up at the moment, as I need to get back to my Horticultural studies. Once I get this block out the way I will attack the detectors with renewed vigor. I have the tacoma56 squareboard SurfDD to box up with a ML 10x5 DD Commander, this has 4 external pots, and the Sniffer XR71 should arrive any day. 7 external pots on that one, and my secohmeter yet to assemble.

Thanks for that heads up, I will revisit this circuit, as I have both the 347 and 348 here.

TL074CN-
Scarborough Low-cost metal detector

[Tim]

Eureka moments.
This has rattled my cage Q. Have you heard of the Eureka Stockade? It was the wholesale massacre of the gold miners of Victoria by the Red Coats. Maybe not as well known as the American War of Independence, but an altogether pivotal moment in Australian history. It is part of what makes us Australian, and is the equivalent theology to American Liberty.
The search for a Eureka moment should not therefore be undertaken without gravity, and it seems that your disregard for other opinions, to the point of not even reading my comments properly, makes you a Red-Coat. It also seems that your disregard for the basics, like a good oscillator design, is likewise indicative of a Red-Coat.
I will admit that some comments with regard to technicalities are beyond me, but because of and in spite of your disregard for others opinions, I still feel there is a silent majority who will glean something from my simplistic ponderings and experiments. Though obviously, you have long since closed your mind to these basics, through some belief that you know it all. Such attitudes are the makings of un-neccessary wars Q. I will not back down. And as you previously targeted me I will never. But I am a diplomatic person, not a war-monger.
Even so, I cannot condone the one-eyed view of Pulse Induction, and find such disregard offensive. It is akin to the belittling of any idea deemed not worthy by you. Not that I am accusing you of belittling, just asking you to give some leeway to us you consider imbeciles. I do realise there are a million threads on here by people who have been unsuccessful building the Surf PI, and the administrators patience must wear thin, but I come into this arena with a lateral perspective. I do not ask already asked questions. I pose new ones. If you find that uncomfortable, then it is yourself you must question, not me you should attack.
For your benefit I will repeat my comment. "Some things may have been overlooked in the search for a Eureka moment". I did not ever say my observations were a Eureka moment. I subtly suggested that you may well have disregarded many.
I came to this site to escape the petty mob mentality and enter into discussion, but it seems the true trolls have been infesting all sites equally. The same knockers with different or similar aliases infest intelligent discussion with-dare I say it again- a purposefully dis-informative corporate mentality. Yep,yep,yep. I'm just paranoid.
Some have now answered my solid ironstone question, to their best ability-thank you all. But all the administrators have done is fill the field with defensive refusal, questions answered with questions, and technical jargon.
So what is the ultimate aim here? To improve detectors and simplify their design, or to create a doctrine to glorify PI with ever more complicated, expensive and un-neccessary digression. ???
Yep,yep,yep. I'm just paraniod. And I must be ruffling feathers for no reason. It must be me who can't see the forest for the trees.

[Nupi]

What is the connection between a BFO and the real Australians, the Aboriginals ?

[Tim]

I suppose that would be persecution and marginalisation by superiorists and supremacists. The same demographic who couldn't differentiate between a BFO and an IB/BB despite long-winded speeches based on Chinese whispers. My BB LF was moved to "BFO discussion", despite not even being a BFO. It is the same manner with which Aboriginals are shoved about and marginalised my misleading and poisonous spiel.
Therein lies the connection, but I fail to see how this truth has any bearing on the actual potential of my design, or relevance to it's improvement.
I never even mentioned the plight of Aboriginals, but I'm glad you bought it up.

Is that the answer you sought Nupi?

[kt315]

http://www.ebay.com/itm/Inductive-Pr...gAAOxy3cJTgEP7