Thanks for the replies to my previous question about replacing a DAB
aerial on a kitchen radio.
I was going to make a small ground plane with a 13" vertical rod through
it, and had located the wire coat hanger, cardboard and silver paper
(mmmm chocolate) and the epoxy to assemble it all.

I then dismantled the radio, freed off the connector and checked
everything out only to discover that there was an intermittent break in
the short piece of thin coax from the pcb to the aerial socket. This
break was not visible - an inch or so down inside the cable.

Replaced the cable, put the broken telescopic aerial back on, extended
it to just under 10" vertically and it now works with only the
occasional burble.

SWMBO is happy, and I'm only slightly embarrassed, as the break only
became really apparent when the coax was flexed with the radio on after
I'd noticed how the inner seemed to move more than the outer. I suspect
the cable has been faulty since the set was new.
--
Bill