Excel tips

 https://pakaccountants.com/excel-dsum-function-explained-with-examples/

Commodore 64 game for free in 2021 = credit:

http://impossible-mission.krissz.hu/

FM tips:

http://electronics-diy.com/6w-fm-transmitter-88-108-mhz.php

http://electronics-diy.com/electronic_schematic.php?id=1030

https://circuits-diy.com/3v-two-transistor-fm-transmitter-circuit/

https://xtronic.org/circuit/audio/circuit-of-stereo-fm-transmitter-hi-fi-with-ic-ba1404-power-stage/

https://www.instructables.com/Arduino-TEA5767-FM-Radio-Receiver/

http://electronics-diy.com/ba1404-fm-stereo-transmitter-with-amplifier.php

https://sci-toys.com/scitoys/scitoys/radio/radio.html

https://www.usefulcomponents.com/main_contents/projects/choccy_block_crystal_radio/choccy_block_crystal_radio.html

http://electronics-diy.com/electronic_schematic.php?id=945

http://electronics-diy.com/BA1404_Stereo_FM_Transmitter.php

https://www.instructables.com/Make-a-RF-Transmitter-and-Receiver-With-HT12E-HT12/

http://www.afiata.com/mini-fm-radio-transmitter-circuit/