Re: What calibration items to buy.
From easy to difficult:
Almost all timebase calibration can be done with a 10 MHz function or
signal generator and frequency counter. The fastest sweeps with
magnification require a 100 MHz or faster source for linearity
adjustment but this is seldom needed.
Vertical calibration can be done with a function generator, AC
voltmeter, and some attenuators but a calibration generator like a
PG506 makes it much faster.
Transient response calibration requires a fast reference level pulse
generator. The PG506 fulfills this function up to at least 100 MHz
but 350 MHz and higher require a faster generator like the tunnel
diode pulser Tektronix recommends. Leo sells one which is suitable
and more than fast enough:
I have an SG503 for generating a leveled sine wave up to 250 MHz but I
have not required it for an oscilloscope calibration yet. The SG504
does not cover low frequencies so both are needed for a full range.