Agilent 346A and N9069A reading high?

Conrad Farlow <conrad@...>

I have access to an Agilent 346A head with an N9069A noise figure measurement application running on an EXA series spectrum analyser. It seems to have number of issues.

1. After calibration the noise figure and gain are never truly zero, the noise figure normally reads -0.1 or similar and the gain will be -0.15 or thereabouts, these are just typical figures.

2.When I measure noise figure I see good results on the gain but the noise figure seems high. For instance my HA8ET Extra 2 LNA reads about 1.4dB whereas I am pretty sure that it is much better than this.

I have Tcold set to the temperature on the surface of the device as measured by a thermocouple. I have used some loss compensation before the device, I have generously allowed 0.1 dB for a high quality female-female N type.

Does anyone have any advice as to what is going wrong? I do have an 8970 that I could use for a reference check but it hasn't been switched on for a while, shocking I know.......

Bit puzzled..



Conrad G0RUZ IO93FR

North Wakefield Radio Club


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