We installed new RFPDs with components s.t. they are tuned near 35.5 MHz. We tuned the inductor L1 and capacitor C40 to bring the peaks and notches to desired values. Attached are TFs and dark noise measurements of these two photodiodes. The transfer function measurements are adjusted with the transfer function of the cables up to the photodiodes. The photodiodes were blocked with a beam dump during measurements and are supplied with +-18 V through the new power strip under the table. In the analysis, 2000 Ohms of DC transimpedance is assumed for TFs. Note: This was a wrong assumption. So do not trust the y-axis. This is a transfer function measurement through test-in ports which could be wrong.
Following are some measured numbers:
RFPD tuned to 37 MHz.
Inductor L1 changed to 146-06J08SL
+5V regulator LM309H replaced with new one.
Measured Peak at 36.882 MHz
Measured Notch at 74.237 MHz
RFPD tuned to 36 MHz.
Measured Peak at 36.247 MHz
Measured Notch at 72.356 MHz
Except for South RFPD being low Q (as it was written on it). the two RFPDs have similar response and same amount of dark noise. This should reduce the contributions from south path in the excess noise measured in the last BN measurement.