PLL Detector

[Fred S]

Has anyone had any luck with the PLL Detector from Kamil Kraus ?

My friend and I built 2 seperate units and no luck yet.

Fred

[Carl]

I breadboarded it a few weeks ago and it did not seem to work, but I never spent any time trying to debug it. Seems ridiculously simple.

Randy was also playing with it, but I never heard any results. Randy???

[Randy Seden]

I spent ALOT of time with my scope trying to figure out why this PLL detector didn't work. Yeah the meter worked and stood at attention just waiting for ANY phase change to make it move, but alas, it waited in vain! Oh well, we all gave our best shot I think.

Randy Seden-Simi Valley,CA.

[Mark Pauls]

I made one too on a breadboard and I could not get any sensitivity from it at all. I tried to vary the internal osc. over a wide area but there was no change. I would have expected that there should be a capacitor across the coil so that it would have a resonance point. Maybe the one Eric posted is better because it looks more like a tradional BFO with two osc. and then you measure the phase difference. Has anybody tried that one yet ?. It could be interesting to combine with a PI unit and have a relay to switch the same coil between the PI and the BFO circuit so you could discriminate when something was found with the PI part.

Mark

[Eric Foster]

http://www.thunting.com/geotech/forum/tech/images/pll2.jpg


Here is the text that accompanies the PLL circuit that I posted from the Signetics Applications Manual.

Eric.

[Rick S]

What would be a good choice for Q2,Q3,Q4 andQ5?
Sorry about the other transistor PLL reply.

[Carl]

Thanks for posting this. Someone tossed out my old Signetics data books years ago. They had some really neat chips back then.

[cary]

hi! it looks that pin 3 go somewhere.the
info from national semi (lm565)also pin 5
go to pin 4 and coil.the data looks like pin
3 go to 1k to 10k hooked to grd.I do not
try it else.good luck!

[Menard]

Try playing with pin 9 of the 565, leave it idle or better connect it to +V with about 100 kOhm.
Maybe the coil will not detect many things but you will see on your scope a nice 2 to 3kHz sawtooh at pin 9 and a rectangular at pin 2.
I have no "scientific" explanation !

JCM