Found a link to the floppy disc head alignment on the MoHP https://www.hpmuseum.org/forum/thread-22003-post-189057.html#pid189057

This section of the site offers RF engineers quick access to popular calculators and design aids. They are useful at design time and for training purposes, both of which stimulated their development and use over the years. Each tool is written in Javascript and the user can view the page source should they wish to examine the implementation.

I have tried to include references to the various books/papers that I have used in the development of each tool and although I have used them all at various times and believe them to be accurate, please use due diligence and further simulate where necessary.

Most of the tools come with sample values pre-entered into each input box to offer a degree of help. I apologise if this bothers you, but from the feedback I receive, it is generally preferred.

Please be sure to have read the "terms of use". The link is available at the bottom of every page.

Found on https://www.ukraa.com/store/categories/e-field-probe/e-field-active-antenna-masthead-amplifier-and-bias-t
The author claims that the capacitance of a cylindrical plate is proportional to its diameter rather than its area.

An analogue frontend is available on https://store.fhdm.xyz/dso-500k

Badger 2040 is a programmable E Paper/eInk/EPD badge, powered by RP2040. Badger 2040 W is a programmable E Paper/eInk/EPD badge with 2.4GHz wireless connectivity, powered by Raspberry Pi Pico W. Both can go into a deep sleep mode between updates to preserve battery.

Hardware to emulate the SPI memory in PCs to speed up the development of free BIOS firmware.
Found on the Oberon mailing list.
See also the articles about retrocomputing and security, e.g. https://trmm.net/Cosign/

Controlling NeoPixel LEDs with a Raspberry pi Pico and Circuit Python.

The websites of the manufacturer Holux are no longer accessible. Holux users will not find any information, downloads (drivers, software etc.) or support at holux.com.
A former technician of Holux Germany and a former Holux specialist dealer are designing this free project. Holux users continue to receive detailed information about Holux GPS devices and support with questions or problems.

With UPS and RTC features, PiSugar2 makes your rpi ready for fast prototyping and product development.

The best compromise between sensitivity and portability
by Luca Feletti and Renato Romero. PCB layout by Jochen Richert.

Detailed description of a shielded magnetic loop antenna for VLF signals