Useful items for purchase

Highly recommended combination:

• https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/
• https://rtl-sdr.com/new-product-rtl-sdr-blog-1090-mhz-ads-b-lna/

USB receivers / dongles:

• rtl-sdr.com v3 dongle: https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/
• Flightaware ProStick Plus: https://www.amazon.com/dp/B01M7REJJW
• Green Radarbox Flightstick: https://www.radarbox24.com/store

Good cheap starting antenna (much better than the whip antennas):

• https://www.ebay.de/itm/253915016420
• requires adapter: https://www.ebay.de/itm/352599709689

Good coax SMA:

• https://www.amazon.de/DELOCK-Stecker-Buchse-CFD200-loss/dp/B00A8FUX40 (Shorter lengths are always better)
• https://www.amazon.com/Delock-Antenna-Cable-Plug-CFD200/dp/B00A8FUX40
• Or via your local supplier LMR195, LMR200, CFD200 cable.

Better, a little pricier antennas:

• https://www.ebay.de/itm/293133285200 (fitting cable https://www.ebay.de/itm/303219313552)
• https://www.amazon.com/1090MHz-ADS-B-Antenna-66cm-26in/dp/B00WZL6WPO
• Premium: https://dpdproductions.com/collections/aviation-base-mobile-antennas/products/ads-b-vertical-outdoor-base-antenna
• All those better antennas require a cable like one of these (male N to male SMA) https://www.amazon.com/MPD-Digital-Shielded-Cable-Connectors/dp/B07RG6BTLC/

Filtered low noise amplifiers (LNAs):

• https://www.rtl-sdr.com/new-product-rtl-sdr-blog-1090-mhz-ads-b-lna/
• https://store.uputronics.com/index.php?route=product/product&path=59&product_id=50

Interesting filter for other amplifiers (i would still prefer an LNA with builtin SAW filter): https://www.ebay.com/itm/1-SMA-M-F-50-VBFZ-1065-Bandpass-Filter-Mini-Circuits-for-FlightAware-1090MHz/132406298935