I found a box full of old radio valves when cleaning my house under coming Christmas.
I desided to make a valve receiver. Some of tubes were brand new.
I had european types like ECL83, ECL84, ECL82, EH90, ECH83, EF95, some 6BE6 tubes,
5MHz xtals and a big tuning capacitor with three sections.
In a PA unit I used a line transformer. A separate main supply gave
about +80V anode voltage and 6V heating voltage. I made all connections
without printed circuits like in old radios. I haven't done a RF state yet, but
I do it later. Power line resistances and capacitors are big ones to handle enough power
and high voltages. My chassis was a thin folded copper plate, a bad one but enough
for the first experiment.
A wire in all coils is about 0,3mm thin.
L2 and L4 are toroids. I had white toroids but I think violets might be better.
L3 has been salvaged from an old radio and made new windings, primary 40 turns and
secondary 8 turns on a 5mm body.
L1 was from same old radio.
L1 = 40 turns, tapped 8 turns from ground, 7,5mm body
L2 = 20 turns, inductance about 27uH, toroid
L3 = 40 turns primary, 8 turns secondary, 5mm body
L4 = 16 turns, 3 twisted wires, the first wire's end to the second wire's begining...
You might need to change a BFO frecuency. Increase a serial inductance or capacitance or
change 47pF and 150pF capacitancies. My version seems to work without modifications.
Find good limits to VFO with TR1 and Cx. I use first a trimmer in a place of Cx,
measured it and repaced with a solid capacitor. A Vfo range is 8.5MHz - 8.8MHz, so a receiving
range is 3.5MHz - 3.8MHz. Connect an antenna, a trimmer to Cy's place and find a good
signal strength in both ends of frequencies, repeat this several times. Measure Cy and replace
with a solid capacitor.
A better body for this radio with a power supply on it and a box for it.
A RF state for example with EF95, AGC, DDS tuning and maybe a valve transmitter.