Ian White GM3SEK wrote in
:

....
RG58 will do fine. Some constructors use small hardline such as UT141,
but mostly for mechanical convenience. At this wavelength, larger
cables are quite difficult to bend into the small loop this is
required.

Ian, I offered that solution elsewhe

===quote
Obsessions about loss aside, try using the calculator to explore a halfwave
of UT141/RG405 semi rigid coax on a 100 ohm load. This is just 0.141" or
4mm diameter, and you need 245mm (as the calculator will tell you). It is a
quite neat solution to a half wave balun if you are not too obsessed about
0.0xdB of loss.
===equote

The loss for UT141 is 0.03dB worse than RG58C/U in this case.

Owen