I still have a video up of the green LED receiver coupled to a single stage of audio. I believe I had the phone up to the headphone. Notice one turn link being adjusted for regeneration. Pot is for audio.
Or to avoid a current reducing LED you can use a K596 FET with a current of a few hundred uA when the gate is at zero, And they are free if you look around as per this video:
Yeh, I remember that circuit. It was slightly prefered to supply the negative bias with a 1.5 V battery (cell) and a very high value potentiometer. However certainly the LED idea is easier. If it behaves, ie. does not "pop" into oscillation it has very good properties of frequency stability and Q multiplication. I must experiment more with it myself and couple a sensitive AM detector to it.
I still have a video up of the green LED receiver coupled to a single stage of audio. I believe I had the phone up to the headphone. Notice one turn link being adjusted for regeneration. Pot is for audio.
https://vimeo.com/201795699
Very cool info, Sean.
Thanks
I love scrounging parts
Or to avoid a current reducing LED you can use a K596 FET with a current of a few hundred uA when the gate is at zero, And they are free if you look around as per this video:
Yeh, I remember that circuit. It was slightly prefered to supply the negative bias with a 1.5 V battery (cell) and a very high value potentiometer. However certainly the LED idea is easier. If it behaves, ie. does not "pop" into oscillation it has very good properties of frequency stability and Q multiplication. I must experiment more with it myself and couple a sensitive AM detector to it.
Need some help? Doug here.
I know, it's different. I missed the old board too. So I put this together. However, it is google seachable and that helps. Great to have you here.