Extend tube radio FM band above 100MHz without RF signal generator

Published at : 23 Dec 2025

Many German tube radios have an FM band that only goes up to 100MHz. So what happens if your favourite station is at 104 MHz? Well, with a load of RF equipment you can easily re-tune it or shift the band limits. But what happens if you don't have this equipment?

I decided to document my attempt to extend my FM band without all the stuff, using a very simple and cheap modern device. Hope it helps you.

This mod is done on a radio that is currently an ongoing restoration project, documented in the following playlist:
https://www.youtube.com/playlist?list=PLy5M_tA9ux7L3k5nPRvrk1aH764QRCTqE

See also my playlists on my other tube radio restorations.

Loewe-Opta Truxa 4741W:
https://www.youtube.com/watch?v=4LFAleeriSM&list=PLy5M_tA9ux7KhVk0KqPx0Wkh2KO_5f2fQ

Graetz Musica 4R417:
https://www.youtube.com/playlist?list=PLy5M_tA9ux7Ios98E59dWjwc2SRJyxwIn

SABA Freiburg W2:
https://www.youtube.com/playlist?list=PLy5M_tA9ux7IqvS-LshUGpE1D_WY6mrZe

Graetz Comedia 616:
https://www.youtube.com/watch?v=fwmW9k3TwNE&list=PLy5M_tA9ux7L5sAApLzV6xoYzmRNJpMW5

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