I have rebuilt my clone GR-81 regen receiver, with a 90 volt plate supply. My voltage range for the 100K regen pot is from 74 volts to 0 volts. Scot Armstrong replied that the 100K regen pot should be replaced with a 10K pot, and that I should insert a 100K fixed resistor between the B+ voltage supply and the 10K regen pot. The ground lug on the 10K pot should then go to ground through a 10K fixed resistor. Scot has not answered my PM`s so far. Can anyone elaborate on how you lower the regen voltage range? Scot stated that about 30+ volts is ideal. Thanks......Lenny

Lenny

Adding extra resistors limits voltage adjustment of the pot. Scot may have determined voltage only needs to be adjust around 30 volts? If that's the case this change would give a limited range of adjustment. Regen pot would be easier to adjust.

I hope Scot Armstrong{ not Dale Armstrong} will answer my PM, and explain what he meant soon! Look at the 6th post by "lennyshere" below this one, and look at Scot`s comments. Maybe you can make more sence out of them than I did! Lenny

I am not a regular on this fourm anymore. Sorry for the delay. I have moved on to other hobbies.

Regens are almost as much art as science. Take the time to learn what you are doing and why. Making a great regen is not done by building from a schematic. You will have to optimize it.

The way they made it you will have between 0 and about 100V. That will work but not be very sensitive. I see it has lots of band switching. To make all bands work all the time you can not optimize it for any one band. I am not surprized you are having trouble with SSB reception.

If you optimize one coil or band by adjusting the tickler turns you can use a smaller range of B+ voltage. I may not work with a different randomly selected coil or band switch setting. The voltage for proper feedback will also be frequency dependant. Regens are not good general coverage sets.

So, in your case try about a 100K between r4 and r3

10 to 50K for r3

about 50K for R2

These are guesses. They will be in the ball park. Get a resistor switch box and subsitiute resistor to get the right result.


What you really need is a "fine regen control". That would involve adding another control. You may not want to modify your set. If you don't mind you could add another pot. A 5 to 10 K added downstream from R3 would work. Come off the whiper of R3 to one end of the resistive element, hang a 100K (or so) resistor off the other end of the element and put the reisitor to ground. Go off the second pot's whiper to the tickler as before. The might give only a few volts change over the range of the pot.

Or finally you could use a variable capacitor. If you add a variable capacitor at the C6 position, to ground, you will get very fine control. Use one in the 100 to 500 pf range.

Hope this helps.

Scot

Thanks, Scot. I assume that the air variable pot replaces capacitor #6. Remove #6, in other words. I have just about completed my mission to build my own regen sw radio. I will move on from there to something else too, probably! Lenny

Leave it in. Use both at the same time. That way the percent change in capacatance will be small. You might try a 500pf or 0.001 in place of the fixed one. Really, you have to try things until they work the way you want. I can not tell you exact values.

If you wanted to get crazy you could put a reduction drive on the variable cap.

I`m crazy. I have a reduction drive on my bandset cap and on my fine tuning cap! I have been using radio shack 100K ohm pots, and I wonder if that has anything to do with my problem. I am going to check out what wattage these things are rated at. I just bought and installed! I just found that they are rated at 1/2 watt. I am about to build a 3-tube superhet, via Lendsey`s " Impoverished Radio Experimenter" #5. I have the old, IF transformers,{ about 3 inches tall and 1 inch by 1 inch wide} so I will not have to make the monstrosities, which they use on this radio.There is a post on" You Tube", where a guy is operating one of these, which he constructed. Lenny