Tweet
Hi all. Way too cold to do much right now! Snow again. More than three inches, country at a halt, people dying etc.No food. No beer in the pubs. So;
I added 10nf across the 47n in the osc. This brought my Tx down to 10KHz (it was 10.8 due to effect of buck coil). Rx was tuned to 10.8 without the 10n. Pretty damn good.
Connected the coil driver to Battery V instead of 5v - 3ma more taken. In free air, detect a 2p piece at 25cm. (That target size will do me, not too many dimes around these parts).
Put coil back to 5v, detect at 22cm - is there any point then in running of the batt ? No. Range will fall as battery v falls too.
Added diode from pin5 of shift reg to get a more pleasing tone - well it is to me.
Changed both 2M7 in the TUNE circuit to 1M5 (because the op amps I used need more bias I).Seems to work but not sure. What should I hear when I flip re-tune ? I think that the 10 after the 220k is supposed to discharge via 2M7 and thus affect the op-amp the 2M7 connects to. Doesn't seem to do too much on mine.
All these tests are in the worst possible environment.
I added 10nf across the 47n in the osc. This brought my Tx down to 10KHz (it was 10.8 due to effect of buck coil). Rx was tuned to 10.8 without the 10n. Pretty damn good.
Connected the coil driver to Battery V instead of 5v - 3ma more taken. In free air, detect a 2p piece at 25cm. (That target size will do me, not too many dimes around these parts).
Put coil back to 5v, detect at 22cm - is there any point then in running of the batt ? No. Range will fall as battery v falls too.
Added diode from pin5 of shift reg to get a more pleasing tone - well it is to me.
Changed both 2M7 in the TUNE circuit to 1M5 (because the op amps I used need more bias I).Seems to work but not sure. What should I hear when I flip re-tune ? I think that the 10 after the 220k is supposed to discharge via 2M7 and thus affect the op-amp the 2M7 connects to. Doesn't seem to do too much on mine.
All these tests are in the worst possible environment.