Beachmaster Files

[surfdetector]

Can we connect a one-meter coil to this circuit?

I think that you should build the Delta Pulse.

[hamedtaran]

Can we connect a one-meter coil to this circuit?

[nickel_n]

thank you Olly

[Olly]

The build document at Beachmaster_1.1.zip
paragraph 3.8 Sample Gates and Integrators

states at 3.8.1 the parts that need to be installed.
there is NO reference to R18 10k, and C9 470nf.
they are on the schematic and pcb.
i think it's a typo and it should be corrected

Thanks for pointing this out, these components are described under the preamplifier section 2.4 but as you have correctly indicated I have omitted to include them in the build description. I'll correct this in the next version of the file.

Regards

[nickel_n]

The build document at Beachmaster_1.1.zip
paragraph 3.8 Sample Gates and Integrators

states at 3.8.1 the parts that need to be installed.
there is NO reference to R18 10k, and C9 470nf.
they are on the schematic and pcb.
i think it's a typo and it should be corrected

[surfdetector]

Hello Olly, I hope you are well. I have a few questions, if the use of those large potentiometers(POTs) is to adjust the pulse width and frequency, etc., then how are they different from small multiturns(RVs)? Second question: What is the best part instead of 2sd? Because I could not buy it
I apologize for my bad English

The PDF describes the functions of the Pots and the RVs. Each one is explained.

[surfdetector]

No test video I'm afraid. As for whether it's better or worse than the Polones and/or ti12000, I really can't say as I'm not familiar with those.
I would say that it works as expected for a mono-coil, analogue, pulse induction detector. I like it, but then I'm biased

The Beachmaster is much more stable than the Polones in my experience.

[hamedtaran]

Hello Olly, I hope you are well. I have a few questions, if the use of those large potentiometers(POTs) is to adjust the pulse width and frequency, etc., then how are they different from small multiturns(RVs)? Second question: What is the best part instead of 2sd? Because I could not buy it
I apologize for my bad English

[surfdetector]

the 2SD1781A is elusive.
20 weeds eta on Digi-Key its been like that for some time

Mouser has them in stock.

[nickel_n]

Thanks Olly

[Olly]

the 2SD1781A is elusive.
20 weeds eta on Digi-Key its been like that for some time

Hmm, that specific part is made by Panjit. I chose it because it has quite a high gain (hfe = 500 typical) and can handle a bit more pwer than most little SOT transistors.
I haven't checked for substitutes but any NPN transistor with a reasonably high gain (say hfe above 300) and able to handle reasonable power (at least 1/2 watt) should be fine if using the audio with headphones.

[nickel_n]

Hope you enjoy building it. What parts are you having problems finding?

the 2SD1781A is elusive.
20 weeds eta on Digi-Key its been like that for some time

[hamedtaran]

No test video I'm afraid. As for whether it's better or worse than the Polones and/or ti12000, I really can't say as I'm not familiar with those.
I would say that it works as expected for a mono-coil, analogue, pulse induction detector. I like it, but then I'm biased

I don't understand what you mean by afraid, anyway i will make it soon

[Olly]

No test video I'm afraid. As for whether it's better or worse than the Polones and/or ti12000, I really can't say as I'm not familiar with those.
I would say that it works as expected for a mono-coil, analogue, pulse induction detector. I like it, but then I'm biased

[hamedtaran]

I haven't made a test video I'm afraid, but 'Surfdetector' has made a very nice series of videos on his YouTube channel about constructing and testing it.
https://www.youtube.com/watch?v=mUWko4utwYc

Thankful. I've seen those videos before, but I haven't seen a test video of the device working. Is this circuit better than Polones circuit? I've already built polones and tl12000