Weird channel anomaly
My incoming aerial signal is amplified after it enters my loft.
It feeds down through the first floor to the ground floor where it is fed
into a socket on a TBS dual tuner card in a computer serving as an HTPC.
This has an output socket from which a cable feeds a Samsung Smart TV sited
Recently one of the channels on the TV said that CBS Drama had moved and to
retune. We did, only to find that channels 20 and 21 were now missing. Prior
to retuning they were there but pixelated.
The anomaly is that they can still be accessed from MythTV on the HTPC,
driving the said TBS card.
Can I get them back on the TV?
Mageia 5.1 for x86_64, Kernel:4.4.39-desktop-2.mga5
KDE version 4.14.5 on an AMD Phenom II X4 Black edition.