Amateurs

https://www.pa3dzl.nl/index.html

https://www.pe1rqm.nl

https://www.radio-romeo-hotel.nl

Diversen

https://www.changpuak.ch/electronics/interdigital_bandpass_filter_designer.php

https://www.dxinfocentre.com/tropo_nwe.html

https://www.dxrapporten.nl

https://datasheetspdf.com

https://pira.cz/rds/show.asp?art=micrords_encoder

https://www.rapidtables.com/convert/power/dBm_to_Watt.html

https://rf-tools.com/lc-filter/

https://winklerantennenbau.de

https://www.worldradiohistory.com/BOOKSHELF-ARH/Bookshelf_ARRL.htm

Shops

https://www.amateurradioshop.nl

https://www.budgetronics.eu/nl/

https://dutchrfshop.nl/en/

https://www.elektrodump.nl

https://nl.farnell.com

https://www.hamshop.nl

https://nl.mouser.com

https://www.reichelt.nl

https://www.vandijkenelektronica.eu/nl/

https://www.winklerantennenbau.de