Hi Charlie! Great to see you back in the saddle, and your soldering-iron out of its holster! Always enjoy the projects and all the explanations and conversation about circuits and their options. I finally retired and managed to get some pretty good used HP gear, so will be getting back into the lab myself. Anyway, thanks for putting out more great videos! 73...
Nice project Charlie, and that variable capacitor looks quite nice. Surprisingly, I found the detector to be the hardest part of an AM RX project. Probably becasue I didn't pay enough attention to the RC time constant of the cap and resistor that comes after the diode. RF Man on RU-vid has an excellent video on this. See too my Q-31 project (my Galaxy V capacitor was like yours, but not quite as nice). 73 Bill N2CQR
Thanks Bill. I did an envelope detector a while back and like you say it took a bit of noodling to get the time constant right. I did find the infinite impedance detector to be better.
I'd report the same experience with my AM Rx project, a 455khz IF receiver si5351, 8 tunable ranges. Everything was easy up to the infinite Z detector. Distortion on AM is easy to hear and once you hear it its hard to ignore it. Choice of JFET made a difference too. I tried the old junk box FETs from my youth, 2n3819, 2n5485, 2n5459. Tuning the RC network would be worth a try too. Good luck and I'll follow your progress. 😀
Nice to see you again. I was very excited to see you starting projects again. I heard infinite impedance detector and franklin oscilator in past. It will be very good to learn and see in your videos. Kind regards
Franklin oscillator works well for me with 2 PNP transistors, here goes: 2x BC557. Emitters connected together then via a 4.7k resistor to +ve. Left hand collector to gnd via coil/capacitor. Right hand collector to gnd. Both bases to gnd via 470k resistor. 22pF capacitor between each base and opposite collector.
So great to have you back Charlie! The project sounds fun and I'm particularly interested in your VFO. I've not built a Franklin oscillator either ... yet! Anyway, welcome back and looking forward to seeing how the radio comes together. 73, Nick M0NTV
Hi Charlie-hope you and your family are good !. Looking forward to this build.Can I ask you- will your calculations be included for this one ! Thanks and all the best Mal
4:00 Use the J310s or at least don't do any "diode as current controlled resistor" type gain adjustment. Not good for linearity, TOI, etc. 4:28 About a year ago I posted a vid of an infinite impedance detector with the BF256B (ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ymVTH9YJaWk.html) works very well. Looking forward to new content from you! 73 de AI5GW
