Hi, what would you suggest for a first Spectrum Analyzer

[fqahmad66]

Rigol is sure noisy but still best bang for buck..

[fqahmad66]

with same setting as of Agilent

[Neganur]

the rigol actually looks quite similar to the agilent, try with the same RBW/VBW and span as in the first screenshot

EDIT: haha, posted while I hit submit. Cheers

[KJDS]

I just took some similar plots with an E4406A for comparison

[G0HZU]

I don't use the old 8568B very much and it's under a desk in another room but I quickly fired it up and set it to 72MHz and a 10kHz span with 10Hz RBW as per the other plots.

Note how I've increased the RF level to 0dBm but you still can't see any noise. This is because the true divider noise level of the synthesiser in that analyser is below the range of the log amp for the display when 10Hz RBW is selected.

I've had to turn off the graticule because it is very fuzzy when the analyser is still cold. The CRT is getting very old now...

It's in a totally different class to anything on this thread and is a classic lab grade analyser rather than a technicians analyser Only the latest analysers that still cost a fortune can beat it and even then they have to resort to trickery with the PLL to reduce the noise level.

This 8568B analyser cost me £125 about 6 years ago.  A tenth of the cost of the Rigol

[G0HZU]

In this image I've zoomed in to a more sensible span for 10Hz operation. i.e. a 1kHz span.

I've dropped the ref level 10dB to bring the noise level into the range of the log amp and you can see that the phase noise is -112dBc/Hz at about a 300Hz offset. So the 0dBm signal is 10dB off the top of the scale and now you can see some noise

This is exactly the same as the spec for phase noise in the HP8568B manual at this offset at frequencies around 70MHz. i.e. -112dBc/Hz at about 300Hz offset.