I'm doing some hobby experiments with AM/FM radio and transmitters. I'm pretty sure the Rigol DSA815-TG is more then enough for that.
Though am thinking in the future to work on 2.4Ghz transivers (for home automation projects). The 815 is limited to 1.5Ghz.
I saw on eBay: HP 8594E 2.9 GHz, and they go for less then $1k (sometimes), but it's older and i'm not sure about their performance and reliability.
I'm new to RF and don't know enough about it to understand if i need the capability to measure beyond 1.5Ghz, when working with 2.4Ghz Transmitters/receivers.
SA is quite an investment after all...
I know this may sound negative, but what do you expect to be using an SA for, particularly at 2.4GHz? Is this for product development, or a bit of tinkering? In that part of the spectrum, it is common to use pre-certified modules with integrated antennas. If it is for EMC precompliance, then as well as the cost of your own test gear, there is also the cost of the compliance house itself which can make the cost of an SA seem quite reasonable.
If it's for home tinkering, then I'd question the real need for an expensive SA other than as a trophy item for the bench: you may well find it sits there gathering dust for months on end while you figure out what you want to use it for.
If you're doing AM/FM narrowband stuff for transmit and receive, I'd seriously consider that instead of purchasing an SA, get a communications/radio test set. Some of them have SAs and even TGs as well, although those SAs are not specifically designed for EMC usage profiles, and often don't go up beyond 1GHz.
Comms test sets have some very useful facets though for AM and FM, in particular signal generators and transmitter testers for measuring receiver sensitivity and transmitter power output and modulation.
Some examples:
Marconi 2955A/B: No SA, to 1GHz CRT
HP 8920A SA/TG option 102, to 1GHz CRT
HP 8920B SA/TG option 102, to 1GHz CRT
HP 8924C SA/TG option 102, to 1GHz CRT
HP 8935 E6380A/E6381A SA/TG + return loss (via external bridge) all standard, to 1GHz, 1.7 to 2GHz, electroluminscent
Agilent E8285A SA/TG option 102, to 1GHz, 1.7 to 2GHz, electroluminscent
Anritsu MT8802A SA option 7, to 3GHz, FM only, no AM, colour LCD
This is quite a useful site:
http://www.amtronix.com/diff.htm