Hello Claudio,

I measured the "backwave" from SAQ a couple of years ago
and found it to be 17dB below the key-down level.

> Any info about SAQ key-up ERP radiated?

I have no exact figure but since the nominal output is 200kW,
and if -17dB is still true, the key-up output power is around
4 kW (!)...

I have been told that SAQ once held the "efficiency record"
for VLF antennas, about 14%, but I have never got that figure
confirmed so take it with a grain of salt. Anyway, the antenna
efficiency is worse today than it was when SAQ was young and
healthy because the performace of the ground system has
deteriorated over time due to corrosion etc.
200 kilometers of copper wire was buried "by hand", without
the aid of machines!

73
Johan SM6LKM