Upgrading VHF (UKW) - A new idea for old devices
A tube radio
excites the enthusiast with its good sound reproduction, the tube
technology, the stylish cabinet and benign details inside as well as
Is is a joy to listen to one's favourite station.
this is limited when the good piece lacks VHF receiption. If the
desired station can be found at all on an AM band (LW, MW or SW), the
pleasure is clouded by bad sound program and background noise.
The solution is
simple. A printed circuit board contains a VHF tuner 87,5-108MHz, an
oscillator that resonates with the radio's built in MW-oscillator
and tunes the VHF receiver and an AM modulated generator for the radio IF. Power supply is mainly derived from the anode voltage. The desired tube
base is included in the price.
printed circuit board can be provided with different tube bases, can be
equipped for specific intermediate frequencies and can be adapted to
mixer tubes. Some tube bases have become rare. In those cases forwarding of an old tube is required. Due to the insulated antenna transformer the VHF
supplement is also usable with all-current (non mains insulated) devices.
radio units are already prepared for VHF receiption. In this case the
printed circuit board can be integrated and wired permanently. So the
AM ranges are preserved.
most cases mounting the VHF supplement into an Audion (e.g.
'Volksempfänger'), a two-circuit or three-circuit receiver is
possible. But this usually
requires additional steps. For this case the modification has to be planned according to the specific device.
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