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Offline xavier
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« Reply #90 on: June 11, 2014, 11:47:54 pm »
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Quote:Posted by pandoraguru
Hi Cornelius

I might be interested to in this BFO detector, can you send me a copy of the full schematic?
Thank you!


Thats not going to happen but if you go to the first page of this thread you will find the schematic

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« Reply #91 on: June 13, 2014, 07:48:17 am »
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Hello Xavier

My mistake! I missunderstand and i believe Cornelius is the owner of that BFO schematic, so thank you for inform me where to look.

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« Reply #92 on: June 13, 2014, 09:01:59 am »
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Cornelius has  been MIA from this form for over a year or so.  Yes he was the poster and what we have is what we have.  I don't think he posted anything in the Down load section but he may have.  Take a look there. 

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« Reply #93 on: June 13, 2014, 12:25:57 pm »
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Ah, i will look, thank you homefire!
Regards

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« Reply #94 on: June 14, 2014, 11:06:56 am »
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By the way that detector works quite well,  I know because I built one a few years ago.

Regards

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« Reply #95 on: November 17, 2016, 01:41:30 pm »
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Quote:Posted by PiksiMC
send me a copy of the schematic pls




Your going to need Stock in Mouser Electronics to build all these detectors.  Again have a look in our Down Load section.  You need to help your self a little bit here.

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« Reply #96 on: June 07, 2020, 09:51:41 am »
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I know this is quite old but...something in this schematic puzzles me for a while now. I keep seeing this in oscillator circuits but Im not exactly sure why. Several of the chips in this circuit are powered through a series resister. I have seen discrete component oscillators done the same way. What is the purpose of this? I am assuming that it is to isolate the oscillations from the power supply but Im not sure. Also the series resistance values here are even higher than I have seen elsewhere. I would have thought that this would have bad effects on overall circuit operation. In other words if the various parts of the circuit are putting a varying load on the power supply then voltages on these chips would be varying also due to the voltage drop on the series resister changing. Hoping someone can shed some light on this.

Thanks.

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Offline Eugene52
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« Reply #97 on: June 07, 2020, 06:29:47 pm »
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Posted on: June 07, 2020, 06:24:46 pm
Quote:Posted by GarrettManRP
I know this is quite old but...something in this schematic puzzles me for a while now. I keep seeing this in oscillator circuits but Im not exactly sure why. Several of the chips in this circuit are powered through a series resister. I have seen discrete component oscillators done the same way. What is the purpose of this? I am assuming that it is to isolate the oscillations from the power supply but Im not sure. Also the series resistance values here are even higher than I have seen elsewhere. I would have thought that this would have bad effects on overall circuit operation. In other words if the various parts of the circuit are putting a varying load on the power supply then voltages on these chips would be varying also due to the voltage drop on the series resister changing. Hoping someone can shed some light on this.

Thanks.


Welcome to this Great Forum Mr. GarrettManRP !!!

I'm not an Engineer but Thank-You very much for your post today. You should not be puzzled at all, Oscillation and noise problems can occur on any PCB circuit board If its not engineered right , I think you know that .
Running Circuit simulations can show a lot when your designing and testing.  If your experimenting Try "LT Spice or equivelant on your BFO Metal Detector circuit that you are wondering about.  I read Colpitts Oscillators are used on BFO's metal detectors because the RF Signal they produce is so CLEAN. Its advantage is also low reactance [Capacitance on high frequency] of LC tank , and is normally what 80 to 100 khz on BFO ??
There are Many different ways to solve noise problems besides resistors. Many Newer VLF schematics are posted on here for reference, check the Download area and you can check the topic search box in the upper right of the front page

BFO's machines were from a long time ago like the picture from 1976 !!!  But they did work good in bad soil because of the high frequency.

I'm not an Design Engineer or Engineer expert. Just a Electronic Bench Technician for several years. I only have AA associate degree as Electronic Technician. I try to help people on here when I can.

There are some members on this Forum who will help you better than me on your design and noise problem. Some on this Forum are Engineers and some others even call themselves experts ,  LOL !!!  


Thank-you and Welcome to this Forum !!!!

Best Wishes to Everyone and Please Stay Safe..................Eugene



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« Last Edit: June 07, 2020, 06:33:33 pm by Eugene52 »
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Offline GarrettManRP
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« Reply #98 on: June 07, 2020, 08:18:17 pm »
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Thanks for the feedback. I recently bought an old 70s Garrett master hunter and a 68 ish Hunter, both in excellent condition. Id love to be able to see Garretts catalog like the one image you posted here. Where can I find these catalog images?

Thanks again.

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Offline Eugene52
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« Reply #99 on: June 07, 2020, 08:43:45 pm »
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Quote:Posted by GarrettManRP
Thanks for the feedback. I recently bought an old 70s Garrett master hunter and a 68 ish Hunter, both in excellent condition. Id love to be able to see Garretts catalog like the one image you posted here. Where can I find these catalog images?

Thanks again.


Catalogs from years ago are out there but they are hard to find, like from the 60s and 70s. I'm sure you know that A lot of metal detector ads ran in old treasure magazines.

1. Search Google for Garrett metal Detectors under "Images"
2. Keep you eyes open for Old Treasure magazines. They are Cool and worth money now.
3. Maybe check the Garrett website for downloads and their history page.

If I wanted a Old Garrett the Master Hunter 7 would sure be nice to have.

Regards................Eugene

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