Hi Eric,
The direction doesn't matter with respect to attenuation
or impedance, but it does matter at which side you apply
the power. Most attenuators are a series of low power
attenuators with increasing attenuation from input to
output. e.g. 0,5 dB 0,5 dB 1 dB 1dB 2 dB . . . . .
All resistors have the same power dissipation, that's why
it is important to know at which terminal the power should
be applied to. The trouble is that you never know what's
under the hood. For low power attenuators there's no real
problem, for high power attenuators there's always a risk
because most aren't built symmetrical.
Don't think that a chunky 1000 watts 30 dB attenuator is
invulnerable, I've seen some being destroyed with 10 watts.
That was also the reason why I asked at which terminal the
power should be applied to, I already fried a few.
on1aag.