This time I got a heptode subminiature tube, 2G21. I guess this tube was widely used in 50's and 60's ? Vacuum tube era pocket radio. I've used MT tube 1R5 heptode and this time I simply swapped it with 2G21, without any parameter modification.

One additional note: Resistor between plate of triode (#3) and GND should be set for 150k (1R5 was 100k), otherwise local oscillator will cease in a few minutes..

As shown in the image, now the radio is fully made by subminiature tube. You may notice two variable capacitor for the radio... YES, the double variable capacitor certainly change both receiving resonator and local oscillator resonator but my ferrite bar antenna does not resonate where I need if I use double variable capacitor. Thus I used independent variable capacitor for receiving resonator. (I have to double tune for local oscillator and receiving resonator, but it is working..) Actual operation can be found in the following movie.. have fun!