Roger,
The last message needs clarification.??
I did try the RSP1A with the Spectrum Analyzer software and found it to be very good for spans up to 10MHz.? When I tried to measure the 3rd harmonic of 14MHz (42MHz) displaying both the fundamental and that harmonic, there were steps in the noise floor and inconsistent level readings that did not maintain step attenuation of the input.? This situation did not happen for the lower span settings.? This is what led me to look for other solutions.
There are ways around the RSP1A issue, namely to measure the values at the lower spans by changing the center or start settings.? With the step in the noise floor, I was not confident of the relationship to the fundamental.? I also found the markers and math to be problematic.? They were hard to get to follow the signal levels when adjusting the step attenuator to validate measurements.? It was better with the last update that I used, but still not consistent and hard to set.
There is also a cost difference.? The TinySA is $50, the RSP1A is $100.? Unfortunately, it still takes both to do all of the purity tests to my way of thinking.? There maybe calibration steps of the RSP1A software that would solve the large span problem.? There may also be ways to measure SSB signals without needing less than 3kHz RBW.
For sure the TinySA will not get an upgrade in the RBW, as that is a hardware filter issue, at least at this point in time.? There may be ways to use digital comparison techniques to narrow down the bandwidth that I am not aware of.? As stated before, there may also be ways to adjust the calibration process of the RSP1A software.? Until then I will use both tools for their appropriate measurements.? The combined cost is still less than the lower cost Rigol SA model.
The above are my opinions based on my experiences.? They may be in error, so it is recommended that you validate if possible.
73
Evan
AC9TU
