Most modern ones are capable of also displaying voltage in some format on the Y-axis, but you're still stuck with that 50-ohm input. Spectrum analyzers are normally meant to give a display of signal power on the Y-axis versus frequency on the X-axis. IF you choose to use the analyzer in ways it was not designed for you need to proceed very carefully and think hard about what you are doing. Spectrum analyzers are wonder tools but they were not made to align the IF of tube amplifiers. I know there are protection diodes but they are not made to take much charge either. for a short time the cap is shorted and will dump dc into the analyzer until the cap charges. The other thing to remember is what happens when you connect the probe to HV. When they fail you will short the input of the probe to the input of the analyzer and it will fail. Many probes are not rated for tube voltages and I have even seen onesįail below the nice rating on the label. Sure the 400V dc will get dropped to safe levels on paper but those probes are really capacitive dividers with tiny caps. I would never use a 10 megohm scope probe as a poor mans divider.
you would need the service manual for pinout and voltage. The tek power supply for the probes is getting scarce but you can find the lemo connectors and use a good external power supply. I use a small coupling cap rated for 1000v DC on the probe tip and I still use a 50ohm dc block connector on the analyzer.
They are DC -1ghz so if you connect to 400V DC you will blow the probe amplifier and if you kill the amp you dump DC into the analyzer and kill it. That said you still need to be very careful. They show up on ebay for less than $100 but are not really repairable.
They came with diviIder hats that allowed 1x through 100X attenuation and pretty good voltage ratings.
The best series of probes was the older 6201 series. As Leigh stated Tek has made some very good FET probes over the years but the prices are pretty high. However I have used spectrum analyzers for years in high impedance circuits. You do not want to blow the input mixer as they are not user serviceable. The menu navigation is very intuitional in use and all functions and parameters are easy to reach because of the graphical interface.As stated previously the input to spectrum analyzers will not tolerate large signals or any significant DC. The Rigol Spectrum Analyzers have a sophisticated and easy to use user interface and offers multiple functions for all tasks. These functions enable the analyzer to acquire signals and match parameters automatically, instead of the manual process necessary with a traditional analyzer. The very large display (20.3 cm / 8") of the Rigol DSA815 Spectrum Analyzer with a resolution of 800x480pixels provides a very good overview over all its comfortable functions like Auto Tune, Auto Range, Auto Scale and Auto Couple. This version is the base unit and does not include the tracking generator. The use of digital IF (intermediate frequency) technology guarantees reliability and performance to meet the most demanding RF applications.
The Rigol DSA815-TG is a compact and light Spectrum Analyzer with premium performance for portable applications.