#26
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Hello Mr. Geo
Thank you for your pcb layout. I think the only thing who will happend when you put LRL in shielded box will be the shielding of transversal EM waves and noise. If you touch antenna and LRL boost signals (make beeps) - he is working in reverse mode. About spurious oscillations i think they were related to noise caused by environmental noise. Franco PLL-LRL is very sensitive to presence of human body near L1-C11-C10-C9-C8-Tr2. If you find again oscillations try to lower 150k resistor from base of Tr1 to ground at 47K-68K. |
#27
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Hi Geo,
The instability is also in open air? On the desk of my laboratory the LRL was unstable, but further away about 60cm became stable. I think the reason was the proximity of the wires carrying 220V mains. Also the connection from point X to pin 14 of CD 4046 it may cause oscillations. I think that the better solution is a double side pcb with the bottom side ground connected, also connection point X - pin 14 it must be on bottom side. With only one side pcb it very easy to get spurious oscillations. Best Regards |
#28
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Geo some hints about instability !!
Make connection from collector Tr4 (point X) to C18 4,7nF to pin 14 CD4046 use short 50 oms coaxial cable RG50U. Outer shield on ground - inner wire from Tr4 to CD4046 will be enough to stop spurious oscillations. Also if you can put a copper strip over CD4046 - glue it and ground strip at one side. PLL4046 is excellent transmitter at 3 MHz. Ideally it should be placed in grounded metalc case. If you can upload oscillograms here in your thread. Will be fine for all other people who make this excellent Franco PLL-LRL. Reg. Enjoykin4 |
#29
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Hi all.
Today i did n't check it because i was busy. Maybe tommorow but i am not sure if my lrl oscillates. When it will work properly will try to attach here oscillograms of every stage. Regards
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Geo |
#30
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For Franco....
Maybe next week to cross Italy. Will you be there or in Switzerland???
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Geo |
#31
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accidentally , I found some yellow cable, much like this in Franco's LRL. So, I expect better performance using this antenna in my Franco PLL |
#32
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Hi Geo,
next Thursday I returned to Italy but only for 2 days for urgent business, unfortunately my wife has a need for help in everyday life, I hope that in the future the situation will improve and that I can devote myself completely to the LRL. Best Regards |
#33
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Hi Bill 512,
yellow is the color of gold... |
#34
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Quote:
Next Thursday (28/1) i will be (90%) at Italy near to Parma... Piacenza.... Do you have any idea or time!!! Regards
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Geo |
#35
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Quote:
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Geo |
#36
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Quote:
Today i found a little free time to check the lrl. There are oscillations between 12 and 16Mhz. I put out from sockets the 4046 and358, and disconnected the L. When i cut the track from TR4 to C18 the oscilations stoped. After it i soldered again the L and oscillations began now at 780 Khz. If will replace C13 and C15 from 560pF with 100 pF there is n't any change. I have let it for tommorow with (maybe) more free time. Regards
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Geo |
#37
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Signore Geo
only one thing come to my mind - amplifier stage together with 4046 make oscillations - and cause for this case is bad board layout design. If you will try new one design for Signore Franco 4046-LRL use original footprins from these pictures. ps: Keep in mind that human body great affect on signal(s). Reg. Enjoykin4 |
#38
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Signore Franco,
Do you like to share with Signore Geo and all of us here on forum - step by step adjusting and trimming procedure of your 4046 PLL-RLR version ( including oscillograph and test field adjustment ? Thanks in advance !! Reg.Enjoykin The GOLDEN SUN JARILO (name of our star) !! |
#39
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Quote:
Hi Enjoy.. I am afraid also that i made bad pcb design, so i will try a new one. I am not sure if it is better to make it with double side pcb and the component side to be shielding or it will work as small capacitances and will create new oscillations. Franco says that the xtal version is better and more simple but i want to try the PLL version. Regards
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Geo |
#40
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Hi All,
In my lab there is a lot of confusion and I have realized more than 10 copies of my LRL plus many other types and do not have the design of PCB, for many LRL I modified an existing PCB, I also do the pcb by hand without the help of PC further I am in Switzerland. As I said it's better a double-sided PCB, although in the case it posted it is a single-sided PCB. And no doubt it's a high frequency realization with high gain which can lead to spurious oscillations. Best Regards |
#41
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Hi Geo,
Next Thursday (28/1) surely I'm in Switzerland and Parma or Piacenza are not near my home (in Switzerland), I think about 500Km. I know Imola where there is a MD dealer. Best Regards |
#42
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Signore Franco how to adjust your PLL 4046 passive scalar sniffer ??
I have already made 3 phantoms with your original pcb layout ( Xtal versions) and they work excellent). Meanwhile i was made 3 PLL with bad Nicolas pcb (4 main mistakes have orrected) but very bad results. These 3 pcb are the worst pcb made in my life. So Signore Franco step 1 is: 1. VCO 4046 at 3MHz {pin 3 and 4}. Pont 9 4046 about 11,4V. Maybe the value of c3 for impulse component {3n3} is too high ? 2. Collector Tr4 {joint point of R16-R17} output of amplifier stage 6Vpp (ac signal - without gold target signal). 3. 4046 phase comparator output -> pin 2 {pointX} DC 6V. Any further advices and ideas ?? ps: O have idea to make reference sugnal with Gennadiy Nikolaev "Siberian Colia" scalar generator and many ideas about different scalar antennas but need a time to make it all. Help or not in any case Thank you signore Franco for reveal the SCALAR PHENOMENON of GOLD and SILVER !! Reg. Enjoykin4 |
#43
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Quote:
Sorry Franco, i understood wrong when you wrote about "Next thursday". Maybe another time, who knows????? Regards
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Geo |
#44
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Hi all.
I found the problem with oscillations. A bad decoupling . I put one capacitor near to emmiter of TR2 and gnd (big distance between emmiter and point(-) of power suply)and now all seems ok. Now i must put the LM358 in socket and check the lrl again.
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Geo |
#45
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Geo if not a problem make a oscillogram snapshots at4046 and lm 358.
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#46
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Will try it but maybe not today.
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Geo |
#47
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Hi enjoykin4,
The better think is if CD4046 doesn't work at max frequency ( 3Mhz and more than 11V at pin 9) with these values, the IC consumes too much power. If the stage TR1 creates problems I think we can eliminate C3, TR1 and P2 and connect pin 4 (VCO out) with C8 (the same with quartz version). You may need only change C8/C9 and verify that at collector TR4 there is about 2-3V (AC signal) although the CD4046 also works 0.5V AC. It's possible that the lrl works in reverse mode. The phase comparator output (pin 2) it's Ok in the range 1-8V but may be impossible tuning by only P3, if the case it's usefull connect a 100K resistor from inverting pin of LM358A to +12V or ground as the case. Best Regards |
#48
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Quote:
Who is the right??? Regards
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Geo |
#49
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Hi Geo,
Correct operation is pcb inside the shielding box and when you touch the antenna and the LED is on, it turns off. If the led is off with target it must go on. I think it is necessary to single screen PC, but not the whole box, as even with the shield covering the box bringing the hand to the front panel there is a signal change. The best thing is to use a long-handled, 25-30 cm. Best Regards |
#50
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Hi Franco.
So my lrl now is correct. After some days will try it at my field test because now we have snow. Regards
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Geo |
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