Is this bitx-40 or bitx20 or uBitx? as they are not the same?
Since it happens with the loop I'd suspect its the radio.? I say that?
as people will run off and blame the endfed half wave.
Generally of the SWR is good its something else.
Things in the radio such as long wires, possible radiation from the board
to antenna connector, grounding issues within the box.
Generally plastic cases being RF transparent are likely to make this worse.
Allison
