The receiver is done....

[VE3GZB]

My miniloop receiver, patterned after the Silver_Marshall Round the World Four, with some deviations to fit my available parts.

Too many picture links to spend time pasting them individually, just look on my server (home computer, on during the day and off at night).

http://99.239.146.96/Projects/Miniloop_radio/

Tube lineup is as follows:
RF preamp tetrode=Cossor 215SG
Regen detector=Cossor 210HL
AF amp=Cossor 210HF

It all runs from a single 90 volt supply, though it can run on a bit less. Regen and screen voltage are derived from the 90 volt input.

Filament supply has been designed to run the 2 volt tubes from as much as 5 volts (commonly available from computer supplies, 7805 voltage regs).

Shielding was found in the prototype to be entirely necessary since the circuitry is extremely sensitive and will feedback onto itself without it.

The shielding copper and copper base is just some double-sided unetched PC boards I had. The copper base is glued to the wood to avoid the ugly screws.

The variocoupler was made from a couple of different diameter cardboard tubes (garbage). The windings are #26 wire, 7uH each, and then gently rolled in hot wax from unscented Ikea white candles I melted down.

[AMroo]

   Looverlie, made any contacts on it?

[VE3GZB]

I don't have a transmitter yet, that's my next project!

But on the prototype, I did listen in on other Rag chewers and broadcasts. This version has improved shielding than my prototype so I hope to expect better performance. I have a better variable cap in this version than in the prototype as well.

[VE3GZB]

I tried it last night, I picked up Radio Havana very loud and clear, also picked up Radio Iceland! It has excellent selectivity and tremendous gain! But regeneration control had room for improvement. So I've updated the receiver today I tried a few different ideas and settled on a throttle cap approach.

My original approach was to use a 500pF cap to "ground" the cold end of the tickler, just before the two RFCs (each 340uH).

I added a small Apron shield just above the Variocoupler because at the top end of reception I found there was still some small tendency for interaction to the loop. I added a 6nf Mica cap to the B+ to make sure I'm not getting any instability due to stray pickup in the power line.

[k4kyv]

I like your use of vintage components, especially before the modifications.  I see a lot of "reproduction" radios using vintage tubes but full of modern parts, or parts clearly from the post WW2 era, and to me that totally spoils the effect.

In the post-modification photos, the knobs look out of period.  I would try to find something more 1920's vintage.  The tube sockets and type A Sangamo mica capacitors give the rig "class".