For all I also decided to do the LRL franco 4046 I have finished construction and I want to do a correct calibration with the help I have activated the device and measure the voltage at 4046 at pin2 has 4.000νDc and when it touches the antenna it drops to 3,300 n (750 mv difference and measures a voltage of 0.900V AC in the collector of TR4 I measured a voltage of 1.224DC and 0.238νAC or the frequency is 3.186MHZ of best wishes in all
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Franco's LRL ver_4046
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For my experience the VCO frequency is better no more than 2.8Mhz (if more CD4046 absorbs too much power) and for TR4 collector is better in the range 4 - 6V (try for R14 = 1.2M and/or for R17 = 3.9K or 3.3K).Remember that the oscilloscope greatly influences the sensor stage and the measurements are not very reliable.Originally posted by teo View PostFor all I also decided to do the LRL franco 4046 I have finished construction and I want to do a correct calibration with the help I have activated the device and measure the voltage at 4046 at pin2 has 4.000νDc and when it touches the antenna it drops to 3,300 n (750 mv difference and measures a voltage of 0.900V AC in the collector of TR4 I measured a voltage of 1.224DC and 0.238νAC or the frequency is 3.186MHZ of best wishes in all
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For all of you franco the first measurements I made is wrong or the measurements I made now without changing the R14 and R17 are at 4046 pin2 2.900νDC and when it touches the antenna 2.600ν difference 300mv and 0.570νAC in the collector TR4 has a voltage of 4,300dDC and when touching the antenna 4.220 V difference 80mv voltage AC 0v the london is active does not turn off when it touches the antenna a help of the best wishes
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I don't understand "the london is active does not turn off". The CD4046 version is not the same as quartz version, it's more difficult to tune because there is not a DC stage that it's also usefull for tuning. Anyway if you have a 300 mV difference when you touch the antenna I think that the sensor stage is ok.Originally posted by teo View PostFor all of you franco the first measurements I made is wrong or the measurements I made now without changing the R14 and R17 are at 4046 pin2 2.900νDC and when it touches the antenna 2.600ν difference 300mv and 0.570νAC in the collector TR4 has a voltage of 4,300dDC and when touching the antenna 4.220 V difference 80mv voltage AC 0v the london is active does not turn off when it touches the antenna a help of the best wishes
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Touching the antenna is an empirical test to check if the sensor stage amplifies correctly, but the real test is on the field with buried metals. The correct gain is just below the point where the compass effect occurs.Originally posted by teo View PostFor everyone on franco I'm sorry for the bad translation where says london is LED when it touches the antenna is not deactivated if you reduce the gain R6 220kΩ will better good wishes
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