[TowerTalk] Coax Loss

[Dan Zimmerman N3OX]

K9YC says:


>  So if you double the length, you
> double the loss.
>

Jim, of course you gave the right answer overall, and of course you meant
you "double the dB loss" but this sentence is the crux of the issue, so I
want to expand with a few examples.

You don't "double the loss" in terms of power out vs. power in by doubling
the length. yet that is what the English language
sentence "you double the loss" suggests.

If the loss in length X is 1.5dB, you end up with 1.41 times the loss in the
doubled length.

If it's 3dB, you double the loss by doubling the cable (this is the special
case :-) )

If the loss is 4.77 dB per unit length, you triple the power loss by
doubling the cable.

If the loss is 7dB in the length you've got, you quintuple the power loss by
doubling the cable.

If it's 10dB, you end up with 10 times the loss in the doubled cable.

- - - - - - - - - - - - -

All of the answers given correctly say "if you double the length, you double
the dB"

But we should be careful with "if you double the length, you double the
loss," because it's the root of this particular confusion.

73
Dan