On Fri, Oct 6, 2017 at 11:35 PM, Jeremy Nichols <jn6wfo@...> wrote:
The 411A is the older, vacuum tube version of the 3406, vintage the same as the 400D/H/L AC and the 412 DC voltmeters.
They are really very different. The 411A uses a traditional diode
detector, that is supposedly linearized through the use of a matched
feedback diode. The 3406A uses a fast sampler to convert the RF input
to an IF frequency for measurement, which is a much more accurate
technique.
