David & Margaret McBeth wrote:
If I join 2 lengths of 93 ohm coax to give 46.5 ohm impedance will the db
loss on the line be greater,less or the same as a single lengthof the coax?
ZL2DG

Assuming the cables are matched in each case, loss is the same.

Think about it this way. You have half the power through each cable.
This means whatever loss you have, each cable now has half the power
loss. When they are summed back together, losses are now the same.

Say you had one cable with 100 watts, and power loss was 1 watt. Now
you use two cables and 50 is 50 watts in each and loss is 1/2 watt. You
sum them together and you get 1 watt loss, and now have 99 watts.

That's the matched case.

In the mismatched case in limited conditions, what Reg says will work.
For example at VHF and lower frequencies most cables are dominated by
conductor losses. At cable less than 1/4 wl long will have decreased
loss when it has some SWR in a direction that decreases current. By
paralleling two cables that are LESS than 1/4 wl long, as long as
conductor resistance losses dominate, you can find situations where
losses decrease if the mismatch is in a direction that decreases line
current.

If the lines are long increased SWR always causes increased loss. You'd
have to be careful to avoid making a change that causes each line to
have increased loss from standing waves, because if that happened line
loss would increase.

Since 93 ohm line has terrible loss, I'd avoid it. A good line would be
a short length of parallel 75 ohm line, but then who needs a 37.5 ohm
line? I did that once on a 160 vertical, but the .05dB power I saved
wasn't the reason. The real reason was so the 35 ohm antenna feedpoint
stayed where it was instead of being transformed by the line.

73 Tom