Surf PI 1.2 increase sensitivity ??

[Tony60]

Well Marty when I start the construction of the TGSL if I have any doubt I will remember your kindness.
Thanks again and have a good evening.
Tony60.

[MartyJ1963]

You're welcome Tony60,,,,Regards Marty.

[Tony60]

Hello ionut_mtb I wrapped the coil recommended by Daverave and the sensitivity is slightly improved. I would like to know how to behave to change the resistance of the coil load. Moreover, by varying the trimpot offset and delay the amplitude of the pulse does not change remains 60uS. As soon as possible I send a photo of pin 6 oscilloscope signal.
Thanks in advance and happy Easted.
Tony60.

[ionut_mtb]

Hello ionut_mtb I wrapped the coil recommended by Daverave and the sensitivity is slightly improved. I would like to know how to behave to change the resistance of the coil load. Moreover, by varying the trimpot offset and delay the amplitude of the pulse does not change remains 60uS. As soon as possible I send a photo of pin 6 oscilloscope signal.
Thanks in advance and happy Easted.
Tony60.

hello,

Check picture, output ne5534 need to be like in picture, if not, you need dumping tool to set right the dumping resistor of coil.
Trimpot offset need to be adjusted for output 5534 to be like in picture.
delay you can see movement at 4094 pin 10.

[Tony60]

Ok Ionut_mtb the track on pin 6 of my 5534 is similar to the one in the picture. I will try with the schematic that I propose to change the amplitude of the signal and bring it to 100 uS. I will keep you informed and many thanks for everything.
Good night.
Tony60.

[6666]

Hi All I have successfully built the surf pi 1.2 the first MD so far. I am very satisfied but I would like to ask you can help me to increase sensitivity. Impulse is 12,5v and about 60 uS lenght of time(analogic oscilloscope). Now , in the air, see a coin of 30mm to 17 cm; I would like to bring it at least 20 cm... I enclose a photo of the PCB and coil.
Thanks in advance and greetings.
Tony60 (For OM also ik2czq).[ATTACH]42655[/ATTACH][ATTACH]42654[/ATTACH]

Why not try for 40cm on one euro ? there is a thread on GT somewhere
http://www.geotech1.com/forums/showt...243#post160243 see post 511 for mods
and even a video, https://www.youtube.com/watch?v=-jsbQ11ZBQE

[Tony60]

Hi 6666 thank you for info.
All the best.
Tony60.