Telephone and telegraph from the Your Life work series - 1946 - Vocational Guidance Films, Inc.

Using Winrad we look at the activity corner of the display. The Softrock v6.1 is on 40m an MT63 or another multitone mode is on the left 4 PSK31 contacts on the right take up less space.

Schematic of the 4 tube radio, experimentally built in a way of the radio-pioneers (1910-1945). The radio acts as a cascade type receiver when the antenna coil has a high self-inductance, with lower self-inductances of the antenna coil you can put in a mixing process with the oscillator. Perhaps...

Experimental receiver for VLF. I received electromagnetic (radio) signals between 14 and 22 KHz with a capacitor of 4,7 NF over the showed coil. The schematic is identical to that of the storm detector IV (with the 6088 Tube), the coil is differently constructed. There is one more transistor...

This is a one valve [tube] radio that believe it or not I constructed 48 years ago. It remained lost but was discovered again during a recent house move. The valve used is a battery R.F. pentode dating from around 1948 on a B7G base. The type number is DF91 or the American equivalent, the 1T4....

Observations of electromagnetic (radio) signals on very low frequencies, 0 KHz - 10 KHz. Observed 10 may 2008, approx. 23.00 hour on 4,5. KHz: next to the original radio resonance of 4,5 KHz there is another resonance (spectrum on approx. 10 KHz), that comes in and fades away after 30 minutes....