Ive purchased one of the first HM5006 back in the nineties of the last century:
https://cdn.rohde-schwarz.com/hameg-archive/hm5005_5006_english.pdfThis machine has the tracking generator fitted, the lowest resolution bandwidth was 12.5 (not 20) kHz and it was powered from an SMPS.
It was an affordable option for hobyists at that time - even cheaper than their top analog oscilloscopes. In fact, as far as I remember, it was equivalent to about €1.100,- back then, wheres a triple beam HM1005 was about €1.500,-
Well, with a RBW of 12.5 or even 20 kHz and a span of only 500 MHz it easily can be fast. Any modern SA can be blazingly fast too under such conditions. The same goes for the FFT on modern scopes under comparable conditions.
This instrument looks like a useless toy by today's standards (in terms of bandwidth and RBW, accuracy, measurements/applications/tools), but it sure had its place among radio amateurs back then. For instance, I particularly bought it when I had to design a crossover network (duplexer) for a 70 cm digipeater - hence also the tracking generator.
Later on, Hameg introduced similar models, with 1 GHz bandwidth and adapted RBW more suitable for EMI pre-compliance testing.