Yeah that probably is an internal battery and all that is just charge controller. Would be nice to run the audio into a FFT spectrogram though so you can let it scream every blip but not get your ears de-sensitised, if my phone had an input I’d give that a try some day, must be an app for that.
This coil I’m building, I don’t know if it’s a measured approximation of the recommended existing detech coil, or Aleksandr’s own design/trial and error, but I’m doing it different enough and the design is fundamental enough that there shouldn’t be any IP stopping me selling them or others if they work, but I wouldn’t assume my first coil to work any better than a detech unit of comparable size when tuned in for maximum Tx.
What I think he’s saying there is this:
Detech SEF 6*8 is good because it’s lighter, seems he may have tuned your unit with that coil.
One should have to adjust the ground balance trimpot only once per coil [the external potentiometer changes the same thing, the trimpot is just to get the right magnitude of effect available on the pot]. Toggle the switches so they’re not discriminating anything, allmet, as seen on the switch diagram [I think that means SW1 in the middle position and SW2, I’m not sure which side to throw that one, try it either way and if turning the discrimination knob does anything with metals nearby, it’s probably the other way.] Get a 5cm long 1cm diameter ferrite rod, like those found inside analog radios or bought from jaycar, to simulate some typical ground, and position it close to the coil. [Adjust the pot to about halfway I guess, so you can increase or decrease the GB from where the trimpot sets it to, I’ve not done this before but it seems to make sense.] Adjust the trimpot until the ferrite is not detected anymore, GB setting done, tweak it with the knob very gently when in the field. [If it’s too delicate you could use a smaller value potentiometer there and repeat setting the trimpot.]
I think it’s currently set to cut out the ferrite when the pot is turned to about 10 o’clock on the dial.
That seems fine, good amount of room either side. If you can turn the gb pot to make such a ferrite disappear somewhere around the middle of the dial then your GB is set up fine.
Today I finally got all my coil winding gadgets made and wound a beautiful ellipse of 65 x 0.35mm copper, loomed with cable ties until I’m ready to tape it. I need to purchase a theoretically usable graphite binder substance tomorrow, once I determine what one.