19/08/2016 18:37

I am unfortunately a little old and remember old radio amateur times. A few months ago I desired to see lighting vacuum tubes again. Because of that fact I designed and constructed RETRO TX QRP which made use of the mix of modern and “classical” parts. Its construction was mostly corresponding with the RETRO style - as it used to be in Eastern Europe about 50 years ago.

The CW TX is equipped with an oscillator for two close bands – almost all CW part of 80 meters (3500 to 3590 kHz) and new 60 meters band (5351.5 to 5366.5 kHz). This new band is not in effect yet. It is expected to be open for HAM operation from January 1th, 2017. The TX uses LC oscillator with a J-FET plus two other J-FETs (separator and impedance transformer). Other levels use vacuum tubes. The output power of the TX is QRP: 5 Watts. A principal scheme is shown in the block diagram. A scheme in detail (wiring diagram) is not published here because the one would need too large place. I can however send the complete scheme in detail via e-mail to everybody who would be interested in this RETRO TX (transmitter). I must also WARN against HIGH VOLTAGE which is used in the TX (up to about 350V). Who will decide to construct and operate this TX has to be very CAREFUL and KEEP all regulations and rules of PROTECTION against high voltage.

You can see the RETRO TX QRP photograph (No.29) and the block diagram (No.28) in the PHOTOGALLERY.





Dr. Greg Latta, AA8V, The W8EXI Wingfood VFO exciter,


Ing. J. Štěpán, Oscilátory v radiových zařízeních, Přednášky z amatérské radiotechniky-1980


Keith A. Kunde, K8KK, Program tankit_v20,


Keith A. Kunde, K8KK, Rapid Class C Plate Tank Design, Electric Radio, January 2011


Keith A. Kunde, K8KK, A Design Aid for Vacuum Tube Linear RF Power Amplifiers,