I'm attaching a table with some measurements and the power spectrum from the pd to help evaluate the numbers.
The box output ranges from 0.5V to 2.1V. The coefficient between power and voltage is negative so higher voltage means lower power.
The red numbers are the outputs from each channel at their resonant frequencies. As one can see these are not very well centered on the dynamic range of the power detectors.
The cross coupling seems to be not a problem.
Even if the 166 filter, which handles the smallest of the frequencies and is also the most lossy (for construction reason), mounts a preamplifier, the output is still rather small. this explain also the high bias due to the noise amplification at the maximum power (13dB). A better insertion loss either remaking the filter or re-tuning that one would simplify many problems, i.e. there is not much room in the metal pomona box to fit the amplifier. I might want to consider, after everything else is ready and if I have time before leaving next week, to work on a new 166 filter. |