Hi Erik,
yes i performed the manual routine and think it is useful. I have a low signal level on my Ultra 407, down by 40 dB, i.e. at -75 dBm. Now your manual says that even with a bad RF switch, if the signal stays within 6 dB of that level when the LNA is enabled, then the LNA is fine. However, on mine, when i enable the LNA, it even goes up to where it should be, -35 dBm. Have you ever had this before ?
The manual testing of the attenuator behaves as it should, the noise floor goes up by as much as the attenuation, maintaining the level @30 MHz.
I ordered new switches.
My conclusion is that my switch makes a low impedance only when it is in normal (non-LNA) mode, and this is rather unusual because typically you expect it makes a low impedance in either position. I hope it is not the attenuator that causes the low impedance but else behaves normally in producing the correct relative levels ?
