Just completed general test, ACED IT. Well done! What additional privileges does the General give you? 73, J.B., VE3EAR Statistics: Posted by J.B. Weazle McCreath — Mon Apr 25, 2022 2:25 pm ..read more

radm49 wrote: ↑ Mon Apr 25, 2022 3:56 am qmavam wrote: ↑ Thu Apr 21, 2022 8:57 pm Yes, you can use a wall wart for power, you might need to add a capacitor (1000uf ?) to filter the ripple so you don't hear it. But that does depend on what type of wall wart. Mikek I bought one of these - https://www.parts-express.com/9-VDC-300 ... er-120-030. I'll find out soon enough about any ripple effect. I should get the order in a few days. Do you think I'll need to add a capacitor? That is a switching supply, it uses a high frequency oscillator to drive a small transformer, rather than a larger 60h ..read more

Congratulations gnuuser! Garry WA1GWH Statistics: Posted by Garry — Mon Apr 25, 2022 11:57 am ..read more

I found this circuit in an old book. I haven't tried it myself but it looks interesting. pocket_regen.JPG Studying the diagram in the book, R1 bottom and wiper are both connected to the bottom of the tuned circuit, pin 3 of the coil. Statistics: Posted by coildog — Mon Apr 25, 2022 9:32 am ..read more

Congratulations! What kind of questions did you get? Is it a multiple choise test? I guess you couldn't have found the questions too difficult since you did so well. Statistics: Posted by coildog — Mon Apr 25, 2022 9:25 am ..read more

qmavam wrote: ↑ Thu Apr 21, 2022 8:57 pm Yes, you can use a wall wart for power, you might need to add a capacitor (1000uf ?) to filter the ripple so you don't hear it. But that does depend on what type of wall wart. Mikek I bought one of these - https://www.parts-express.com/9-VDC-300 ... er-120-030. I'll find out soon enough about any ripple effect. I should get the order in a few days. Do you think I'll need to add a capacitor? I also need advice about an additional component. I'm going to be using the Adapter to power 4 of the AMP boards and will need to split the output. I want to av ..read more

Just completed general test, ACED IT. ( 7 minutes time) Could have went on to extra but I'd rather study and make sure I pass. Statistics: Posted by gnuuser — Sun Apr 24, 2022 8:58 pm ..read more

Thanks, Dave. I added a 100R as you described and can now tune most of the band without needing to touch up the mixer. Statistics: Posted by allthumbs — Sun Apr 24, 2022 3:39 pm ..read more

It's not the LO tuning that's "super sharp," it's the mixer tuning. That that tuning is "super sharp" is likely because the mixer input is regenerative. A 47- to, oh, 470-ohm resistor between the 6K8's input tuned circuit and grid cap may serve to quiet that down; regeneration occurs when the input impedance of the affected stage looks (somewhat) negative, so a little positive R in series with the control grid can offset it. Going to a toroidal input coil may help, as toroids have very little external magnetic field. Ganging in such a simple circuit is largely a confection that serves mainly ..read more

Thanks for the kind remarks, gents. The crystal filter in the i.f. was not functional so I spent this morning removing it, disassembling it, cleaning it with alcohol, reassembling it, buttoning up the enclosure, trying it out -- only to find that the crystal seems to be a dud, then repeating the disassembly process, removing the crystal again, substituting an HC/6U (?) type crystal (I had a 455 KHz one in the boîte du junque), reassembling everything and trying it out again. Success! The HRO i.f. is an impressive piece of work. Now that I know I can build a working converter, I'm going to tr ..read more