8902A -110db above 1.3 Ghz

[measure]

Hawaii,
I can't address your uncertainty questions right now, but I can tell you that I used both an Agilent PSA with N5531S Measuring Receiver option as well as an R&S FSMR daily for over six months, minimum, and the FSMR is much better and faster to use than the Agilent/Keysight PSA. Not that the Keysight doesn't meet its specifications, because it does. But the FSMR is significantly faster with a lower standard deviation in its measurements than its PSA/N5531S counterpart, in my experience. If it was my money, I wouldn't hesitate to purchase the FSMR as its a heckuva machine!

Are you aware that to verify the FSMR attenuation accuracy that the manufacturer sells a cal kit, the FSMR-Z2, calibrated by the PTB in Germany?

Good Luck on the Uncertainty Number Crunching!

[CalLabSolutions]

I agree and have also worked with all of them in the past.. The PSA / N5531S has an issue with the CPU, it is just not powerful enough.

Last month I developed a new drives for the PXA for Metrology.NET, and I have to say Keysight got it right.  The AM/FM/PM demodulation is super fast and the CPU has clock cycles to spare.  I have not done a side by side comparison but I was able to test a PSG's demodulation in seconds. 

The PXA doesn't have the N553x Configuration, but if uncertainties are an issue you are better off without the sensor heads.  The heads... All of them add uncertainties to your measurement. The 117xx heads had a switch that introduces errors, and the N55xx heads have a power splitter and attenuator in the heads that introduces flatness errors.

My recommendation is to not use any of the heads.  Take the ref reading directly with a power sensor then transfer that reading to the 8902A, PSA or PXA.. Then perform tuned level from that point down.  (Note.. This is how Keysight does it!)
** It is important to note the PSA/N5531A can make accurate and faster measurements using the spectrum analyzer function.  This is also available in the PXA. 

I am recommending to all of my customers looking for an updated measurement system.. Look at the PXA or UXA with a Power Meter and Power Sensor, way faster and way more accurate.

Mike

[briansalomon]

CalLabSoloutions - Thank you for the information. I have run a couple of measurements of an 8340B attenuator at 20Ghz in TRF without the head and it works.

Since the only frequency the 8902A sees through the down converter is the offset (I am using 120.53 Mhz) I am now wondering why the 11792A head is there at all.

[Bryan]

The head contains a switch to power sensor or thru path.
When you measure RF Power you are using the sensor, when you switch over to tuned RF you'll hear the switch get thrown and I you are using the 8902A to measure the IF (120.053MHz) relative to the RF level measured by the sensor or something like that.

[silv3rstr3]

I haven't used one of those heads since the military.  I remember it being a pain to have to manually enter the cal factors.  Much simpler to just use a power meter and sensor to measure RF power and connect directly to the 8902A for tuned RF. 

[Hawaii596]

I know what you're saying about entering the factors.  We keep sensors married to a given 8902A (we have about three systems in service).  So we only have to do it once a year for each system.  I end up printing our the page from the operators guide each time, and after you've done a few, it's not too bad.