Roy, W7EL wrote:
"---the loss with a given wire size gets greater as you go lower in
frequency,---.

Effective resistance to r.f, is approximately proportional to the square
root of the frequency due to "skin effect" as Roy mentioned in
describing how current penetrates the conductor less completelty due to
inductance deeper in the wire. So, loss is greater at higher frequency
due to reduced effective cross-section in the wire. Conversely, the loss
with a given wire size gets lower as you go down in frequency.

Best regards, Richard Harrison, KB5WZI