Homemade superheterodyne radio

Description

This radio is based on three tubes: ECH81, EBF89, ECL86. Input circuitry is hand wound coil on a PCV pipe with ferrite rod inside. Radio roughly covers the long wave band 150-350KHz. The tracking of local oscillator is not great but I was able to receive Polish Radio 1 on 225KHz. The intermediate frequency (IF) is 463KHz and two filters come from 1950s Pionier U radio. The radio does not have AGC (automatic gain control) and all stages were made on the go following data sheets.
The power supply and speaker are enclosed in one case, the receiver is mounted on wooden board, both are covered in veneer with shellac politure. Both parts are made in art deco style. The third part of a set is a frame antenna made in similar style. It is actually an active antenna with EF80 tube working as an amplifier and additional tunable RF filter at the output, for now it is not tuned to long wave but part of short wave.
The ECH81 serves as a mixer and oscillator, the oscillator uses Hartley topology and coil is hand wound. Mixer is followed by first IF filter. EBF89 is a pentode that works as a IF amplifier and two diodes as AM detector. Output of the IF amplifier goes through second IF filter and then to detector where audio is retrieved from Am signal. The final tube is ECL86 which provides two stages of audio amplification. First is triode and then power pentode. Output of tube amplifier has high impedance so transformer is used to bring it down to around 4 Ohms.
The power supply uses transformer with center tap and full bridge rectifier and provides around 250V DC under load and 6.3V AC for heaters.

Next version

I have also made version with AGC and magic eye. This radio has band switch and rudimentary dial. So far only one bad was implemented. Nice addition is a loop antenna similar to typical AA5. This radio is not that good looking but uses Armstrong oscillator, offers much better tracking and lower distortion.