Can anyone suggest a good supplier of electronic components and 300 ohm
feeder in Germany, ideally that has a website from which I can order. I am
only wanting small quantities for home construction.
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Conrad for general electronic components(similar to Maplins in the UK)

Kusch for 300 and 450 Ohms balanced feeder ,coax, coax connectors, etc
Kusch is a family company visiting most AR-rallies/fleamarkets in D and NL

Both companies have web sites

Frank KN6WH / GM0CSZ